497

                                                     March 21, 2013

VIA ELECTRONIC TRANSMISSION

Securities and Exchange Commission

100 F Street, NE

Washington, DC 20549

Re:     Harbor Funds

    File Nos. 33-5852 and 811-4676

Ladies and Gentlemen:

Attached hereto for filing on behalf of Harbor Commodity Real Return Strategy Fund and Harbor Unconstrained Bond Fund pursuant to the Securities Act of 1933, as amended, and Rule 497(c) thereunder, and the Investment Company Act of 1940, as amended, are exhibits containing interactive data format of risk/return summary information included in the supplement, filed pursuant to Rule 497(c) on March 6, 2013, to the Harbor Strategic Markets Funds Prospectus, dated March 1, 2013.

If you have any questions or comments concerning the foregoing or the attached, please contact the undersigned at (312) 443-4420.

Sincerely,

/s/ Charles F. McCain

Charles F. McCain

Chief Compliance Officer

Cc:     Christopher P. Harvey, Esq.

    Stephanie A. Capistron, Esq.

    Dechert LLP

    David G. Van Hooser

    Anmarie S. Kolinski

    Erik D. Ojala, Esq.

    Susan A. DeRoche

    Harbor Funds

    Shanna Palmersheim, Esq.

    Harbor Capital Advisors, Inc.

P.O. Box 804660 | Chicago, Illinois 60680-4108

800-422-1050 | www.harborfunds.com

Distributed by Harbor Funds Distributors, Inc.

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Harbor Unconstrained Bond Fund

Harbor Unconstrained Bond Fund
Fund Summary

Investment Objective

The Fund seeks total return.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses Harbor Unconstrained Bond Fund		Institutional Class	Administrative Class
Management Fees		0.85%	0.85%
Distribution and/or Service (12b-1) Fees		none	0.25%
Other Expenses		0.60%	0.60%
Interest Expense from Sale-Buyback Transactions		0.02%	0.02%
Other Operating Expenses		0.58%	0.58%
Total Annual Fund Operating Expenses		1.45%	1.70%
Expense Reimbursement	[1]	0.38%	0.38%
Total Annual Fund Operating Expenses After Expense Reimbursement	[1]	1.07%	1.32%

Expense Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, under these assumptions, your costs would be:

Expense Example Harbor Unconstrained Bond Fund (USD $)	One Year	Three Years	Five Years	Ten Years
Institutional Class	109	421	756	1,703
Administrative Class	134	499	887	1,977

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund’s performance. The Fund’s portfolio turnover rate in the most recent fiscal year was 1,262%.

Principal Investment Strategy

Principal Style Characteristics: Broad range of fixed income instruments without benchmark constraints or significant sector/instrument limitations

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its net assets, plus borrowings for investment purposes, in a diversified portfolio of fixed income instruments of varying maturities, which may be represented by derivatives such as options, forwards and futures contracts, or swap agreements. The Fund intends to utilize various investment strategies in a broad array of fixed income sectors to achieve its investment objective. The Fund will not be constrained by management against an index. The average portfolio duration of this Fund will normally vary from negative three (-3.0) years to positive eight (8.0) years based on the Subadviser’s forecast for interest rates.

The Fund may invest in both investment-grade securities and “high-yield” securities (“junk” bonds) subject to a maximum of 40% of its total assets in below investment-grade securities. The Fund may also invest without limitation in securities denominated in foreign currencies and in U.S. dollar-denominated securities of foreign issuers. In addition, the Fund may invest up to 50% of its total assets in securities and instruments that are economically tied to emerging market countries. The Fund will normally limit its foreign currency exposure (from non-U.S. dollar-denominated securities or currencies) to 35% of its total assets. The Fund may also invest up to 10% of its total assets in preferred stocks.

The Fund may invest substantially in derivative instruments, such as options, forwards and futures contracts or swap agreements, or in mortgage- or asset-backed securities. The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis and may engage in short sales. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Principal Risks

Investors considering an investment in the Fund should be prepared to accept significant volatility in the Fund’s performance, particularly over shorter time periods, due to the unconstrained nature of the Fund’s investment approach. Investors should also be sure they carefully read and understand the range of investment strategies and instruments that the Fund may use and the heightened risks associated with those strategies and instruments.

There is no guarantee that the investment objective of the Fund will be achieved. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Fixed income securities fluctuate in price in response to various factors, including changes in interest rates, changes in market conditions and issuer-specific events, and the value of your investment in the Fund may go down. This means that you could lose money on your investment in the Fund or the Fund may not perform as well as other possible investments. Principal risks include:

Unconstrained strategy risk: Because the Subadviser employs an unconstrained investment approach, the Fund’s portfolio may have significant exposure to certain types of securities and instruments, credit qualities, maturities, countries and regions that are not represented in a similar manner or in similar weightings as that of the Fund’s benchmark index or other broad market domestic or foreign fixed income indices.

As a result, there is a significantly greater risk that the Fund may substantially underperform the Fund’s benchmark index and other broad market fixed income indices for long periods of time if the Subadviser’s judgment about the attractiveness of particular securities proves to be incorrect. In addition, because of this unconstrained approach, the Fund’s performance may be significantly more volatile (that is, experience much greater and more frequent highs and lows) than the Fund’s benchmark index and other broad market fixed income indices. Potential investors should only consider investing in this Fund if they understand and are willing to accept the heightened risks and volatility associated with this type of unconstrained investment approach.

Interest rate risk: As interest rates rise, the values of fixed income securities held by the Fund are likely to decrease and reduce the value of the Fund’s portfolio. Securities with longer durations tend to be more sensitive to changes in interest rates and are usually more volatile than securities with shorter durations. For example, a 5 year average duration generally means the fixed income security will decrease in value by 5% if interest rates rise by 1%. Interest rates in the U.S. are at, or near, historic lows, which may increase the Fund’s exposure to risks associated with rising rates.

Credit risk: The issuer of a security owned by the Fund could default on its obligation to pay principal or interest or its credit rating could be downgraded. Likewise, a counterparty to a derivative or other contractual instrument owned by the Fund could default on its obligation. This risk is higher for below investment-grade securities.

Prepayment risk: When interest rates are declining, the issuer of a pass-through security, such as a mortgage-backed or an asset-backed security, may exercise its option to prepay principal earlier than scheduled, forcing the Fund to reinvest in lower yielding securities.

Selection risk: The Subadviser’s judgment about the attractiveness, value and potential appreciation of a particular security may be incorrect.

Derivatives risk: The value of derivative instruments held by the Fund may not change in the manner expected by the Subadviser, which could result in disproportionately large losses to the Fund.

Foreign securities risk: Because the Fund may invest in securities of foreign issuers, an investment in the Fund is subject to special risks in addition to those of U.S. securities. These risks include heightened political and economic risks, greater volatility, currency fluctuations, higher transaction costs, delayed settlement, possible foreign controls on investment, and less stringent investor protection and disclosure standards of foreign markets. Foreign securities are sometimes less liquid and harder to value than securities of U.S. issuers. These risks are more significant for issuers in emerging market countries. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market.

Emerging market risk: Foreign securities risks are more significant in emerging market countries, such as those in Eastern Europe, Latin America and the Pacific Basin. These countries may have relatively unstable governments and less- established market economies than developed countries. Emerging markets may face greater social, economic, regulatory and political uncertainties. These risks make emerging market securities more volatile and less liquid than securities issued in more developed foreign countries.

Short sales risk: If the price of securities sold short increases, the Fund would be required to pay more to replace the borrowed securities than the Fund received on the sale of the securities. Because there is theoretically no limit to the amount of the increase in price of the borrowed securities, the Fund’s risk of loss on a short sale is potentially unlimited.

Mortgage risk: Mortgage derivatives in the Fund’s portfolio may have especially volatile prices because the embedded leverage can magnify the impact of the extension or contraction event on the underlying cash flow. There may be a greater risk that the Fund could lose money due to prepayment and extension risks because the Fund invests heavily at times in mortgage-related securities.

High-yield risk: There is a greater risk that the Fund will lose money because it invests in high-yield bonds. These securities are considered speculative because they have a higher risk of issuer default, are subject to greater price volatility and may be illiquid.

Equities risk: The values of equity securities, such as preferred stocks, may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. Equity securities generally have greater price volatility than fixed income securities.

Leveraging risk: The Fund’s use of certain investments, such as derivative instruments or reverse repurchase agreements, and certain transactions, such as securities purchased on a when-issued, delayed delivery or forward commitment basis, can give rise to leverage within the Fund’s portfolio, which could cause the Fund’s returns to be more volatile than if leverage had not been used.

Market and Issuer risk: The value of securities owned by the Fund may go up or down, sometimes rapidly or unpredictably, due to factors affecting securities markets generally or particular industries. The value of a security may decline for a reason directly related to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods or services.

Liquidity risk: A particular investment may be difficult to purchase or sell and the Fund may be unable to sell illiquid securities at an advantageous time or price or achieve its desired level of exposure to a certain sector.

Performance

The following bar chart and table show two aspects of the Fund: volatility and performance. The bar chart shows the volatility — or variability — of the Fund’s annual total returns over time, and shows that Fund performance can change from year to year. The table shows the Fund’s average annual total returns for certain time periods compared to the returns of a broad-based securities index. The bar chart and table provide some indication of the risks and potential rewards of investing in the Fund. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. To obtain updated performance information please visit the Fund’s website at www.harborfunds.com or call 800-422-1050.

Calendar Year Total Returns for Institutional Class Shares

The Fund’s best and worst calendar quarters during this time period were:

	Total Return		Quarter/Year
Best Quarter		2.71%	3rd/2012
Worst Quarter		-1.29%	4th/2010

Average Annual Total Returns — As of December 31, 2012

Average Annual Total Returns Harbor Unconstrained Bond Fund	One Year	Five Years	Ten Years	Life of Fund	Inception Date
Institutional Class	8.00%			4.36%	Apr. 01, 2010
Institutional Class After Taxes on Distributions	7.02%			3.49%	Apr. 01, 2010
Institutional Class After Taxes on Distributions and Sale of Fund Shares	5.20%			3.21%	Apr. 01, 2010
Administrative Class	7.81%			4.11%	Apr. 01, 2010
BofA Merrill Lynch USD 3-Month LIBOR Constant Maturity (reflects no deduction for fees, expenses or taxes)	0.51%			0.39%
Barclays U.S. Aggregate Bond (reflects no deduction for fees, expenses or taxes)	4.22%			6.08%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to shareholders who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only. After-tax returns for the Administrative Class shares will vary.

[1] The Adviser has contractually agreed to limit the Fund's operating expenses, excluding Interest Expense from Sale-Buyback Transactions, through February 28, 2014. Only the Board of Trustees may modify or terminate this agreement.

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Harbor Commodity Real Return Strategy Fund

Harbor Commodity Real Return Strategy Fund
Fund Summary

Investment Objective

The Fund seeks maximum real return, consistent with prudent investment management.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses Harbor Commodity Real Return Strategy Fund		Institutional Class	Administrative Class
Management Fees	[1]	0.81%	0.81%
Distribution and/or Service (12b-1) Fees		none	0.25%
Other Expenses		0.23%	0.23%
Interest Expense from Sale-Buyback Transactions		0.06%	0.06%
Other Operating Expenses		0.17%	0.17%
Total Annual Fund Operating Expenses	[1]	1.04%	1.29%
Expense Reimbursement	[2]	0.04%	0.04%
Total Annual Fund Operating Expenses After Expense Reimbursement	[1][2]	1.00%	1.25%

Expense Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, under these assumptions, your costs would be:

Expense Example Harbor Commodity Real Return Strategy Fund (USD $)	One Year	Three Years	Five Years	Ten Years
Institutional Class	102	327	570	1,267
Administrative Class	127	405	704	1,553

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund’s performance. The Fund’s portfolio turnover rate in the most recent fiscal year was 474%.

Principal Investment Strategy

Principal Style Characteristics: Commodity-linked derivative instruments backed by a portfolio of inflation-indexed and other fixed income instruments

The Fund seeks to achieve its investment objective by investing under normal market conditions in commodity-linked derivative instruments backed by a portfolio of inflation-indexed securities and other fixed income instruments. Rather than invest directly in physical commodities, the Fund employs an enhanced index strategy. The commodity-linked derivative instruments in which the Fund primarily invests are linked to the Dow Jones-UBS Commodity Index Total Return^SM (the “Commodity Index”), which is intended to provide the Fund with exposure to the investment returns of the commodities markets as represented by the Commodity Index without the Fund investing directly in physical commodities. Commodity-linked derivative instruments in which the Fund may invest include commodity index-linked notes, swap agreements, commodity options, futures and options on futures. The assets used to collateralize the commodity-linked derivative instruments are invested in an actively managed portfolio of inflation-indexed bonds and other fixed income securities, including derivative fixed income instruments. The Fund may engage in short selling, which is the sale by the Fund of a borrowed security. The Fund also may invest in common and preferred stocks as well as convertible securities of issuers in commodity-related industries.

The Commodity Index tracks the returns of futures contracts in different physical commodities. The Commodity Index is structured to seek to provide diversified commodity exposure by requiring that no related group of commodities may constitute more than 33% of the index and no single commodity may constitute more than 15% or less than 2% of the index. The value of the Commodity Index, and therefore the value of any derivative instruments linked to that index, may be affected by overall market movements and other factors affecting the value of a particular industry or commodity, such as weather, disease, embargoes or political and regulatory developments.

The Fund will seek to gain exposure to the commodity markets primarily through investments in leveraged or unleveraged commodity index-linked notes and through investments in Harbor Cayman Commodity Fund Ltd., a wholly-owned subsidiary of the Fund organized under the laws of the Cayman Islands (the “Subsidiary”). Commodity index-linked notes are derivative debt instruments with principal and/or coupon payments linked to the performance of commodity indices. The Subsidiary has the same investment objective and is subject to substantially the same investment policies and restrictions as the Fund, except that the Subsidiary (unlike the Fund) may invest without limitation in commodity-linked swap agreements and other commodity-linked derivative instruments. The Subsidiary is advised by Harbor Capital Advisors and subadvised by PIMCO. The Fund may invest up to 25% of its total assets in the Subsidiary.

The derivative instruments in which the Fund and the Subsidiary primarily intend to invest are instruments linked to the Commodity Index. However, the Subadviser also seeks to generate additional incremental return over that of the Commodity Index by seeking to take advantage of temporary market fluctuations in the manner in which the Fund creates exposure to the Commodity Index. The Fund’s or the Subsidiary’s investments in commodity-linked derivative instruments may include exposure to commodity futures with different roll dates, reset dates or contract months than those specified within the Commodity Index. The Fund or the Subsidiary may also invest in derivative instruments linked to the value of a particular commodity or commodity futures contract, or a subset of commodities or commodity futures contracts. As a result, the commodity-linked derivatives component of the Fund’s portfolio may deviate from the returns of the Commodity Index. The Fund or the Subsidiary also may over-weight or under-weight its exposure to the Commodity Index, or a subset of commodities, such that the Fund may have a greater or lesser exposure to that index than the value of the Fund’s net assets, or greater or lesser exposure to a subset of commodities than is represented by a particular commodity index. These deviations will frequently be the result of temporary market fluctuations, and under normal circumstances the Fund will seek to maintain notional exposure to the Commodity Index within 5% (plus or minus) of the value of the Fund’s net assets.

The Fund may invest up to 30% of its total assets in securities denominated in foreign currencies and may invest beyond this limit in U.S. dollar denominated securities of foreign issuers. The Fund may invest up to 10% of its total assets in securities and instruments that are economically tied to emerging market countries. The Fund will normally limit its foreign currency exposure (from non-U.S. dollar-denominated securities or currencies) to 20% of its total assets. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls). The Fund also may invest up to 10% of its total assets in preferred stocks.

The Fund is non-diversified, which means that it may concentrate its assets in a smaller number of issuers than a diversified fund. In addition, the Fund may concentrate its assets in particular sectors of the commodities market.

Duration. The average portfolio duration of the fixed income portion of the Fund will vary based on the Subadviser’s forecast for interest rates, but under normal market conditions is not expected to exceed ten years. Average duration is the weighted average of all bond durations in the Fund’s portfolio, and is an approximate measure of the sensitivity of the market value of the Fund’s fixed income holdings to changes in interest rates. If the Fund’s duration is longer than the market’s duration, the Fund’s fixed income assets would experience a greater change in value when interest rates are rising or falling than would the market as a whole.

Credit Quality. The Fund may invest up to 10% of its total assets in below investment-grade securities, commonly referred to as “high-yield” or “junk” bonds. For all securities other than mortgage-related securities, the Fund may invest in below investment-grade securities only if they are rated B or higher by Moody’s, S&P or Fitch, or, if unrated, determined to be of comparable quality. For mortgage-related securities, the Fund may invest in securities of any credit quality, including those rated below B.

Principal Risks

Investors considering an investment in the Fund should be prepared to accept significant volatility in the Fund’s performance, particularly over shorter time periods. The Fund is not intended to serve as a core holding in an investor’s portfolio but instead should represent only a small portion of an investor’s overall diversified portfolio. Investors considering an investment in this Fund should be sure they carefully read and understand the investment strategies employed and the heightened risks associated with those strategies.

There is no guarantee that the investment objective of the Fund will be achieved. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Commodities and commodity-linked derivative instruments can be significantly more volatile than other securities, such as stocks or bonds. Similarly, the Commodity Index can be significantly more volatile than broad market equity and fixed income indices. The value of your investment in the Fund may go down, which means that you could lose money on your investment in the Fund or the Fund may not perform as well as other possible investments. Principal risks include:

Commodity risk: The Fund’s investments in commodity-linked derivative instruments may subject the Fund to significantly greater volatility than investments in traditional securities. The value of commodity-linked derivative instruments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates or factors affecting a particular industry or commodity, such as a drought, floods, weather, livestock disease, embargoes, tariffs and international economic, political and regulatory developments. The Fund may concentrate its assets in a particular sector of the commodities market (such as oil, metal or agricultural products). As a result, the Fund may be more susceptible to risks associated with those sectors.

Fixed income security risk: Fixed income securities fluctuate in price in response to various factors, including changes in interest rates, changes in market conditions and issuer-specific events.

Subsidiary risk: By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The derivatives and other investments held by the Subsidiary generally are similar to those that are permitted to be held by the Fund and are subject to the same risks that apply to similar investments if held directly by the Fund. The Subsidiary is not registered under the Investment Company Act of 1940 (the “Investment Company Act”), and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the Investment Company Act. In addition, changes in the laws of the United States and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in this Prospectus and the Statement of Additional Information and could adversely affect the Fund.

Tax risk: The ability of the Fund to gain commodity exposure as contemplated may be adversely affected by future legislation, regulatory developments, interpretive guidance or other actions by the Internal Revenue Service or the Treasury Department.

Regulatory risk: The Commodity Futures Trading Commission has recently adopted amendments to CFTC Rules, which, when fully implemented with related regulations, will subject the Fund to regulation by the CFTC, including registration, disclosure and operational requirements governing commodity pools. Certain of the CFTC regulations that would apply to the Fund as a commodity pool have not yet been adopted, and it is unclear what the effect of those rules would have on the Fund if adopted.

Interest rate risk: As nominal interest rates rise, the values of fixed income securities held by the Fund are likely to decrease and reduce the value of the Fund’s portfolio. Securities with longer durations tend to be more sensitive to changes in interest rates, and are usually more volatile than securities with shorter durations. For example, a 5 year average duration generally means the fixed income security will decrease in value by 5% if interest rates rise by 1%.

A nominal interest rate can be described as the sum of a real interest rate and an expected inflation rate. Inflation-indexed securities, including U.S. Treasury inflation protected securities (“TIPS”), decline in value when real interest rates rise. In certain interest rate environments, such as when real interest rates are rising faster than nominal interest rates, inflation-indexed securities may experience greater losses than other fixed income securities with similar durations. Interest rates in the U.S. are at, or near, historic lows, which may increase the Fund’s exposure to risks associated with rising rates.

Credit risk: The issuer of a security owned by the Fund could default on its obligation to pay principal or interest or its credit rating could be downgraded. Likewise, a counterparty to a derivative or other contractual instrument owned by the Fund could default on its obligation. This risk is higher for below investment-grade securities.

Prepayment risk: When interest rates are declining, the issuer of a pass-through security, such as a mortgage-backed or an asset-backed security, may exercise its option to prepay principal earlier than scheduled, forcing the Fund to reinvest in lower yielding securities.

Selection risk: The Subadviser’s judgment about the attractiveness, value and potential appreciation of a particular security may be incorrect.

Derivatives risk: The value of derivative instruments held by the Fund may not change in the manner expected by the Subadviser, which could result in disproportionately large losses to the Fund.

Leveraging risk: The Fund’s use of certain investments, such as derivative instruments, and certain transactions, such as securities purchased on a when-issued, delayed delivery or forward commitment basis, can give rise to leverage within the Fund’s portfolio, which could cause the Fund’s returns to be more volatile than if leverage had not been used.

Foreign securities risk: Because the Fund may invest in securities of foreign issuers, an investment in the Fund is subject to special risks in addition to those of U.S. securities. These risks include heightened political and economic risks, greater volatility, currency fluctuations, higher transaction costs, delayed settlement, possible foreign controls on investment, and less stringent investor protection and disclosure standards of foreign markets. Foreign securities are sometimes less liquid and harder to value than securities of U.S. issuers. These risks are more significant for issuers in emerging market countries. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market.

Non-diversification risk: Because the Fund is non-diversified and may invest a greater percentage of its assets in securities of a single issuer, and/or invest in a relatively small number of issuers, it is more susceptible to risks associated with a single economic, political or regulatory occurrence than a more diversified portfolio. Some of those issuers may also present substantial credit or other risks.

Short sales risk: If the price of securities sold short increases, the Fund would be required to pay more to replace the borrowed securities than the Fund received on the sale of the securities. Because there is theoretically no limit to the amount of the increase in price of the borrowed securities, the Fund’s risk of loss on a short sale is potentially unlimited.

Mortgage risk: Mortgage derivatives in the Fund’s portfolio may have especially volatile prices because the embedded leverage can magnify the impact of the extension or contraction event on the underlying cash flow. There may be a greater risk that the Fund could lose money due to prepayment and extension risks because the Fund invests heavily at times in mortgage-related securities.

Performance

The following bar chart and table show two aspects of the Fund: volatility and performance. The bar chart shows the volatility — or variability — of the Fund’s annual total returns over time, and shows that Fund performance can change from year to year. The table shows the Fund’s average annual total returns for certain time periods compared to the returns of a broad-based securities index. The bar chart and table provide some indication of the risks and potential rewards of investing in the Fund. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. To obtain updated performance information please visit the Fund’s website at www.harborfunds.com or call 800-422-1050.

Calendar Year Total Returns for Institutional Class Shares

The Fund’s best and worst calendar quarters during this time period were:

	Total Return		Quarter/Year
Best Quarter		15.34%	4th/2010
Worst Quarter		-32.91%	4th/2008

Average Annual Total Returns — As of December 31, 2012

Average Annual Total Returns Harbor Commodity Real Return Strategy Fund	One Year	Five Years	Ten Years	Life of Fund	Inception Date
Institutional Class	5.19%			(1.48%)	Sep. 02, 2008
Institutional Class After Taxes on Distributions	4.60%			(3.55%)	Sep. 02, 2008
Institutional Class After Taxes on Distributions and Sale of Fund Shares	3.43%			(2.45%)	Sep. 02, 2008
Administrative Class	4.96%			(1.74%)	Sep. 02, 2008
Dow Jones-UBS Commodity Index Total Return℠ (reflects no deduction for fees, expenses or taxes)	(1.06%)			(6.79%)

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to shareholders who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only. After-tax returns for the Administrative Class shares will vary.

[1] Management Fees, Total Annual Fund Operating Expenses and Total Annual Fund Operating Expenses After Expense Reimbursement have been restated to reflect current fees.

[2] The Adviser has contractually agreed to limit the Fund's operating expenses, excluding Interest Expense from Sale-Buyback Transactions, through February 28, 2014. Only the Board of Trustees may modify or terminate this agreement.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

HARBOR FUNDS

Prospectus Date

rr_ProspectusDate

Mar. 01, 2013

Harbor Commodity Real Return Strategy Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Harbor Commodity Real Return Strategy Fund
Fund Summary

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks maximum real return, consistent with prudent investment management.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses of the Fund

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

February 28, 2014

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund’s performance. The Fund’s portfolio turnover rate in the most recent fiscal year was 474%.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

474.00%

Expenses Restated to Reflect Current [Text]

rr_ExpensesRestatedToReflectCurrent

Management Fees, Total Annual Fund Operating Expenses and Total Annual Fund Operating Expenses After Expense Reimbursement have been restated to reflect current fees.

Expense Example [Heading]

rr_ExpenseExampleHeading

Expense Example

Expense Example Narrative [Text Block]

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This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, under these assumptions, your costs would be:

Strategy [Heading]

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Principal Investment Strategy

Strategy Narrative [Text Block]

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Principal Style Characteristics: Commodity-linked derivative instruments backed by a portfolio of inflation-indexed and other fixed income instruments

The Fund seeks to achieve its investment objective by investing under normal market conditions in commodity-linked derivative instruments backed by a portfolio of inflation-indexed securities and other fixed income instruments. Rather than invest directly in physical commodities, the Fund employs an enhanced index strategy. The commodity-linked derivative instruments in which the Fund primarily invests are linked to the Dow Jones-UBS Commodity Index Total Return^SM (the “Commodity Index”), which is intended to provide the Fund with exposure to the investment returns of the commodities markets as represented by the Commodity Index without the Fund investing directly in physical commodities. Commodity-linked derivative instruments in which the Fund may invest include commodity index-linked notes, swap agreements, commodity options, futures and options on futures. The assets used to collateralize the commodity-linked derivative instruments are invested in an actively managed portfolio of inflation-indexed bonds and other fixed income securities, including derivative fixed income instruments. The Fund may engage in short selling, which is the sale by the Fund of a borrowed security. The Fund also may invest in common and preferred stocks as well as convertible securities of issuers in commodity-related industries.

The Commodity Index tracks the returns of futures contracts in different physical commodities. The Commodity Index is structured to seek to provide diversified commodity exposure by requiring that no related group of commodities may constitute more than 33% of the index and no single commodity may constitute more than 15% or less than 2% of the index. The value of the Commodity Index, and therefore the value of any derivative instruments linked to that index, may be affected by overall market movements and other factors affecting the value of a particular industry or commodity, such as weather, disease, embargoes or political and regulatory developments.

The Fund will seek to gain exposure to the commodity markets primarily through investments in leveraged or unleveraged commodity index-linked notes and through investments in Harbor Cayman Commodity Fund Ltd., a wholly-owned subsidiary of the Fund organized under the laws of the Cayman Islands (the “Subsidiary”). Commodity index-linked notes are derivative debt instruments with principal and/or coupon payments linked to the performance of commodity indices. The Subsidiary has the same investment objective and is subject to substantially the same investment policies and restrictions as the Fund, except that the Subsidiary (unlike the Fund) may invest without limitation in commodity-linked swap agreements and other commodity-linked derivative instruments. The Subsidiary is advised by Harbor Capital Advisors and subadvised by PIMCO. The Fund may invest up to 25% of its total assets in the Subsidiary.

The derivative instruments in which the Fund and the Subsidiary primarily intend to invest are instruments linked to the Commodity Index. However, the Subadviser also seeks to generate additional incremental return over that of the Commodity Index by seeking to take advantage of temporary market fluctuations in the manner in which the Fund creates exposure to the Commodity Index. The Fund’s or the Subsidiary’s investments in commodity-linked derivative instruments may include exposure to commodity futures with different roll dates, reset dates or contract months than those specified within the Commodity Index. The Fund or the Subsidiary may also invest in derivative instruments linked to the value of a particular commodity or commodity futures contract, or a subset of commodities or commodity futures contracts. As a result, the commodity-linked derivatives component of the Fund’s portfolio may deviate from the returns of the Commodity Index. The Fund or the Subsidiary also may over-weight or under-weight its exposure to the Commodity Index, or a subset of commodities, such that the Fund may have a greater or lesser exposure to that index than the value of the Fund’s net assets, or greater or lesser exposure to a subset of commodities than is represented by a particular commodity index. These deviations will frequently be the result of temporary market fluctuations, and under normal circumstances the Fund will seek to maintain notional exposure to the Commodity Index within 5% (plus or minus) of the value of the Fund’s net assets.

The Fund may invest up to 30% of its total assets in securities denominated in foreign currencies and may invest beyond this limit in U.S. dollar denominated securities of foreign issuers. The Fund may invest up to 10% of its total assets in securities and instruments that are economically tied to emerging market countries. The Fund will normally limit its foreign currency exposure (from non-U.S. dollar-denominated securities or currencies) to 20% of its total assets. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls). The Fund also may invest up to 10% of its total assets in preferred stocks.

The Fund is non-diversified, which means that it may concentrate its assets in a smaller number of issuers than a diversified fund. In addition, the Fund may concentrate its assets in particular sectors of the commodities market.

Duration. The average portfolio duration of the fixed income portion of the Fund will vary based on the Subadviser’s forecast for interest rates, but under normal market conditions is not expected to exceed ten years. Average duration is the weighted average of all bond durations in the Fund’s portfolio, and is an approximate measure of the sensitivity of the market value of the Fund’s fixed income holdings to changes in interest rates. If the Fund’s duration is longer than the market’s duration, the Fund’s fixed income assets would experience a greater change in value when interest rates are rising or falling than would the market as a whole.

Credit Quality. The Fund may invest up to 10% of its total assets in below investment-grade securities, commonly referred to as “high-yield” or “junk” bonds. For all securities other than mortgage-related securities, the Fund may invest in below investment-grade securities only if they are rated B or higher by Moody’s, S&P or Fitch, or, if unrated, determined to be of comparable quality. For mortgage-related securities, the Fund may invest in securities of any credit quality, including those rated below B.

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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Investors considering an investment in the Fund should be prepared to accept significant volatility in the Fund’s performance, particularly over shorter time periods. The Fund is not intended to serve as a core holding in an investor’s portfolio but instead should represent only a small portion of an investor’s overall diversified portfolio. Investors considering an investment in this Fund should be sure they carefully read and understand the investment strategies employed and the heightened risks associated with those strategies.

There is no guarantee that the investment objective of the Fund will be achieved. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Commodities and commodity-linked derivative instruments can be significantly more volatile than other securities, such as stocks or bonds. Similarly, the Commodity Index can be significantly more volatile than broad market equity and fixed income indices. The value of your investment in the Fund may go down, which means that you could lose money on your investment in the Fund or the Fund may not perform as well as other possible investments. Principal risks include:

Commodity risk: The Fund’s investments in commodity-linked derivative instruments may subject the Fund to significantly greater volatility than investments in traditional securities. The value of commodity-linked derivative instruments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates or factors affecting a particular industry or commodity, such as a drought, floods, weather, livestock disease, embargoes, tariffs and international economic, political and regulatory developments. The Fund may concentrate its assets in a particular sector of the commodities market (such as oil, metal or agricultural products). As a result, the Fund may be more susceptible to risks associated with those sectors.

Fixed income security risk: Fixed income securities fluctuate in price in response to various factors, including changes in interest rates, changes in market conditions and issuer-specific events.

Subsidiary risk: By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The derivatives and other investments held by the Subsidiary generally are similar to those that are permitted to be held by the Fund and are subject to the same risks that apply to similar investments if held directly by the Fund. The Subsidiary is not registered under the Investment Company Act of 1940 (the “Investment Company Act”), and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the Investment Company Act. In addition, changes in the laws of the United States and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in this Prospectus and the Statement of Additional Information and could adversely affect the Fund.

Tax risk: The ability of the Fund to gain commodity exposure as contemplated may be adversely affected by future legislation, regulatory developments, interpretive guidance or other actions by the Internal Revenue Service or the Treasury Department.

Regulatory risk: The Commodity Futures Trading Commission has recently adopted amendments to CFTC Rules, which, when fully implemented with related regulations, will subject the Fund to regulation by the CFTC, including registration, disclosure and operational requirements governing commodity pools. Certain of the CFTC regulations that would apply to the Fund as a commodity pool have not yet been adopted, and it is unclear what the effect of those rules would have on the Fund if adopted.

Interest rate risk: As nominal interest rates rise, the values of fixed income securities held by the Fund are likely to decrease and reduce the value of the Fund’s portfolio. Securities with longer durations tend to be more sensitive to changes in interest rates, and are usually more volatile than securities with shorter durations. For example, a 5 year average duration generally means the fixed income security will decrease in value by 5% if interest rates rise by 1%.

A nominal interest rate can be described as the sum of a real interest rate and an expected inflation rate. Inflation-indexed securities, including U.S. Treasury inflation protected securities (“TIPS”), decline in value when real interest rates rise. In certain interest rate environments, such as when real interest rates are rising faster than nominal interest rates, inflation-indexed securities may experience greater losses than other fixed income securities with similar durations. Interest rates in the U.S. are at, or near, historic lows, which may increase the Fund’s exposure to risks associated with rising rates.

Credit risk: The issuer of a security owned by the Fund could default on its obligation to pay principal or interest or its credit rating could be downgraded. Likewise, a counterparty to a derivative or other contractual instrument owned by the Fund could default on its obligation. This risk is higher for below investment-grade securities.

Prepayment risk: When interest rates are declining, the issuer of a pass-through security, such as a mortgage-backed or an asset-backed security, may exercise its option to prepay principal earlier than scheduled, forcing the Fund to reinvest in lower yielding securities.

Selection risk: The Subadviser’s judgment about the attractiveness, value and potential appreciation of a particular security may be incorrect.

Derivatives risk: The value of derivative instruments held by the Fund may not change in the manner expected by the Subadviser, which could result in disproportionately large losses to the Fund.

Leveraging risk: The Fund’s use of certain investments, such as derivative instruments, and certain transactions, such as securities purchased on a when-issued, delayed delivery or forward commitment basis, can give rise to leverage within the Fund’s portfolio, which could cause the Fund’s returns to be more volatile than if leverage had not been used.

Foreign securities risk: Because the Fund may invest in securities of foreign issuers, an investment in the Fund is subject to special risks in addition to those of U.S. securities. These risks include heightened political and economic risks, greater volatility, currency fluctuations, higher transaction costs, delayed settlement, possible foreign controls on investment, and less stringent investor protection and disclosure standards of foreign markets. Foreign securities are sometimes less liquid and harder to value than securities of U.S. issuers. These risks are more significant for issuers in emerging market countries. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market.

Non-diversification risk: Because the Fund is non-diversified and may invest a greater percentage of its assets in securities of a single issuer, and/or invest in a relatively small number of issuers, it is more susceptible to risks associated with a single economic, political or regulatory occurrence than a more diversified portfolio. Some of those issuers may also present substantial credit or other risks.

Short sales risk: If the price of securities sold short increases, the Fund would be required to pay more to replace the borrowed securities than the Fund received on the sale of the securities. Because there is theoretically no limit to the amount of the increase in price of the borrowed securities, the Fund’s risk of loss on a short sale is potentially unlimited.

Mortgage risk: Mortgage derivatives in the Fund’s portfolio may have especially volatile prices because the embedded leverage can magnify the impact of the extension or contraction event on the underlying cash flow. There may be a greater risk that the Fund could lose money due to prepayment and extension risks because the Fund invests heavily at times in mortgage-related securities.

Risk Lose Money [Text]

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The value of your investment in the Fund may go down, which means that you could lose money on your investment in the Fund or the Fund may not perform as well as other possible investments.

Risk Nondiversified Status [Text]

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Non-diversification risk: Because the Fund is non-diversified and may invest a greater percentage of its assets in securities of a single issuer, and/or invest in a relatively small number of issuers, it is more susceptible to risks associated with a single economic, political or regulatory occurrence than a more diversified portfolio. Some of those issuers may also present substantial credit or other risks.

Risk Not Insured Depository Institution [Text]

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An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

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Performance

Performance Narrative [Text Block]

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The following bar chart and table show two aspects of the Fund: volatility and performance. The bar chart shows the volatility — or variability — of the Fund’s annual total returns over time, and shows that Fund performance can change from year to year. The table shows the Fund’s average annual total returns for certain time periods compared to the returns of a broad-based securities index. The bar chart and table provide some indication of the risks and potential rewards of investing in the Fund. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. To obtain updated performance information please visit the Fund’s website at www.harborfunds.com or call 800-422-1050.

Performance Information Illustrates Variability of Returns [Text]

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The bar chart shows the volatility — or variability — of the Fund’s annual total returns over time, and shows that Fund performance can change from year to year. The table shows the Fund’s average annual total returns for certain time periods compared to the returns of a broad-based securities index.

Performance Availability Phone [Text]

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800-422-1050

Performance Availability Website Address [Text]

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www.harborfunds.com

Performance Past Does Not Indicate Future [Text]

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The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Bar Chart [Heading]

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Calendar Year Total Returns for Institutional Class Shares

Bar Chart Closing [Text Block]

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The Fund’s best and worst calendar quarters during this time period were:

	Total Return		Quarter/Year
Best Quarter		15.34%	4th/2010
Worst Quarter		-32.91%	4th/2008

Performance Table Heading

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Average Annual Total Returns — As of December 31, 2012

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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Actual after-tax returns depend on a shareholder’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to shareholders who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

Performance Table One Class of after Tax Shown [Text]

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After-tax returns are shown for Institutional Class shares only. After-tax returns for the Administrative Class shares will vary.

Performance Table Narrative

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to shareholders who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only. After-tax returns for the Administrative Class shares will vary.

Harbor Commodity Real Return Strategy Fund | Institutional Class

Risk/Return:

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Management Fees

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0.81%

^[1]

Distribution and/or Service (12b-1) Fees

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none

Interest Expense from Sale-Buyback Transactions

rr_Component1OtherExpensesOverAssets

0.06%

Other Operating Expenses

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0.17%

Other Expenses

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0.23%

Total Annual Fund Operating Expenses

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1.04%

^[1]

Expense Reimbursement

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0.04%

^[2]

Total Annual Fund Operating Expenses After Expense Reimbursement

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1.00%

^[1],[2]

One Year

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102

Three Years

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327

Five Years

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570

Ten Years

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1,267

2009

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30.59%

2010

rr_AnnualReturn2010

23.53%

2011

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(7.66%)

2012

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5.19%

Highest Quarterly Return, Label

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Best Quarter

Highest Quarterly Return, Date

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Dec. 31, 2010

Highest Quarterly Return

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15.34%

Lowest Quarterly Return, Label

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Worst Quarter

Lowest Quarterly Return, Date

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Dec. 31, 2008

Lowest Quarterly Return

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(32.91%)

One Year

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5.19%

Five Years

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Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

(1.48%)

Inception Date

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Sep. 02, 2008

Harbor Commodity Real Return Strategy Fund | Administrative Class

Risk/Return:

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Management Fees

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0.81%

^[1]

Distribution and/or Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Interest Expense from Sale-Buyback Transactions

rr_Component1OtherExpensesOverAssets

0.06%

Other Operating Expenses

rr_Component2OtherExpensesOverAssets

0.17%

Other Expenses

rr_OtherExpensesOverAssets

0.23%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.29%

^[1]

Expense Reimbursement

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0.04%

^[2]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_NetExpensesOverAssets

1.25%

^[1],[2]

One Year

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127

Three Years

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405

Five Years

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704

Ten Years

rr_ExpenseExampleYear10

1,553

One Year

rr_AverageAnnualReturnYear01

4.96%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

(1.74%)

Inception Date

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Sep. 02, 2008

Harbor Commodity Real Return Strategy Fund | After Taxes on Distributions | Institutional Class

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

4.60%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

(3.55%)

Inception Date

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Sep. 02, 2008

Harbor Commodity Real Return Strategy Fund | After Taxes on Distributions and Sale of Fund Shares | Institutional Class

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

3.43%

Five Years

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Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

(2.45%)

Inception Date

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Sep. 02, 2008

Harbor Commodity Real Return Strategy Fund | Dow Jones-UBS Commodity Index Total Return℠ (reflects no deduction for fees, expenses or taxes)

Risk/Return:

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One Year

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(1.06%)

Five Years

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Ten Years

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Life of Fund

rr_AverageAnnualReturnSinceInception

(6.79%)

[1] Management Fees, Total Annual Fund Operating Expenses and Total Annual Fund Operating Expenses After Expense Reimbursement have been restated to reflect current fees.

[2] The Adviser has contractually agreed to limit the Fund's operating expenses, excluding Interest Expense from Sale-Buyback Transactions, through February 28, 2014. Only the Board of Trustees may modify or terminate this agreement.

XML

Document and Entity Information	12 Months Ended
	Mar. 01, 2013
Risk/Return:
Document Type	Other
Document Period End Date	Oct. 31, 2012
Registrant Name	HARBOR FUNDS
Central Index Key	0000793769
Amendment Flag	false
Document Creation Date	Mar. 06, 2013
Document Effective Date	Mar. 06, 2013
Prospectus Date	Mar. 01, 2013

XML

Label

Element

Value

Risk/Return:

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Registrant Name

dei_EntityRegistrantName

HARBOR FUNDS

Prospectus Date

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Mar. 01, 2013

Harbor Unconstrained Bond Fund

Risk/Return:

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Risk/Return [Heading]

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Harbor Unconstrained Bond Fund
Fund Summary

Objective [Heading]

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Investment Objective

Objective, Primary [Text Block]

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The Fund seeks total return.

Expense [Heading]

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Fees and Expenses of the Fund

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Operating Expenses Caption [Text]

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Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

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February 28, 2014

Portfolio Turnover [Heading]

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Portfolio Turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund’s performance. The Fund’s portfolio turnover rate in the most recent fiscal year was 1,262%.

Portfolio Turnover, Rate

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1262.00%

Expense Example [Heading]

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Expense Example

Expense Example Narrative [Text Block]

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This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, under these assumptions, your costs would be:

Strategy [Heading]

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Principal Investment Strategy

Strategy Narrative [Text Block]

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Principal Style Characteristics: Broad range of fixed income instruments without benchmark constraints or significant sector/instrument limitations

The Fund seeks to achieve its investment objective by investing under normal circumstances at least 80% of its net assets, plus borrowings for investment purposes, in a diversified portfolio of fixed income instruments of varying maturities, which may be represented by derivatives such as options, forwards and futures contracts, or swap agreements. The Fund intends to utilize various investment strategies in a broad array of fixed income sectors to achieve its investment objective. The Fund will not be constrained by management against an index. The average portfolio duration of this Fund will normally vary from negative three (-3.0) years to positive eight (8.0) years based on the Subadviser’s forecast for interest rates.

The Fund may invest in both investment-grade securities and “high-yield” securities (“junk” bonds) subject to a maximum of 40% of its total assets in below investment-grade securities. The Fund may also invest without limitation in securities denominated in foreign currencies and in U.S. dollar-denominated securities of foreign issuers. In addition, the Fund may invest up to 50% of its total assets in securities and instruments that are economically tied to emerging market countries. The Fund will normally limit its foreign currency exposure (from non-U.S. dollar-denominated securities or currencies) to 35% of its total assets. The Fund may also invest up to 10% of its total assets in preferred stocks.

The Fund may invest substantially in derivative instruments, such as options, forwards and futures contracts or swap agreements, or in mortgage- or asset-backed securities. The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis and may engage in short sales. The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of purchase and sale contracts or by using other investment techniques (such as buy backs or dollar rolls).

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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Investors considering an investment in the Fund should be prepared to accept significant volatility in the Fund’s performance, particularly over shorter time periods, due to the unconstrained nature of the Fund’s investment approach. Investors should also be sure they carefully read and understand the range of investment strategies and instruments that the Fund may use and the heightened risks associated with those strategies and instruments.

There is no guarantee that the investment objective of the Fund will be achieved. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Fixed income securities fluctuate in price in response to various factors, including changes in interest rates, changes in market conditions and issuer-specific events, and the value of your investment in the Fund may go down. This means that you could lose money on your investment in the Fund or the Fund may not perform as well as other possible investments. Principal risks include:

Unconstrained strategy risk: Because the Subadviser employs an unconstrained investment approach, the Fund’s portfolio may have significant exposure to certain types of securities and instruments, credit qualities, maturities, countries and regions that are not represented in a similar manner or in similar weightings as that of the Fund’s benchmark index or other broad market domestic or foreign fixed income indices.

As a result, there is a significantly greater risk that the Fund may substantially underperform the Fund’s benchmark index and other broad market fixed income indices for long periods of time if the Subadviser’s judgment about the attractiveness of particular securities proves to be incorrect. In addition, because of this unconstrained approach, the Fund’s performance may be significantly more volatile (that is, experience much greater and more frequent highs and lows) than the Fund’s benchmark index and other broad market fixed income indices. Potential investors should only consider investing in this Fund if they understand and are willing to accept the heightened risks and volatility associated with this type of unconstrained investment approach.

Interest rate risk: As interest rates rise, the values of fixed income securities held by the Fund are likely to decrease and reduce the value of the Fund’s portfolio. Securities with longer durations tend to be more sensitive to changes in interest rates and are usually more volatile than securities with shorter durations. For example, a 5 year average duration generally means the fixed income security will decrease in value by 5% if interest rates rise by 1%. Interest rates in the U.S. are at, or near, historic lows, which may increase the Fund’s exposure to risks associated with rising rates.

Credit risk: The issuer of a security owned by the Fund could default on its obligation to pay principal or interest or its credit rating could be downgraded. Likewise, a counterparty to a derivative or other contractual instrument owned by the Fund could default on its obligation. This risk is higher for below investment-grade securities.

Prepayment risk: When interest rates are declining, the issuer of a pass-through security, such as a mortgage-backed or an asset-backed security, may exercise its option to prepay principal earlier than scheduled, forcing the Fund to reinvest in lower yielding securities.

Selection risk: The Subadviser’s judgment about the attractiveness, value and potential appreciation of a particular security may be incorrect.

Derivatives risk: The value of derivative instruments held by the Fund may not change in the manner expected by the Subadviser, which could result in disproportionately large losses to the Fund.

Foreign securities risk: Because the Fund may invest in securities of foreign issuers, an investment in the Fund is subject to special risks in addition to those of U.S. securities. These risks include heightened political and economic risks, greater volatility, currency fluctuations, higher transaction costs, delayed settlement, possible foreign controls on investment, and less stringent investor protection and disclosure standards of foreign markets. Foreign securities are sometimes less liquid and harder to value than securities of U.S. issuers. These risks are more significant for issuers in emerging market countries. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market.

Emerging market risk: Foreign securities risks are more significant in emerging market countries, such as those in Eastern Europe, Latin America and the Pacific Basin. These countries may have relatively unstable governments and less- established market economies than developed countries. Emerging markets may face greater social, economic, regulatory and political uncertainties. These risks make emerging market securities more volatile and less liquid than securities issued in more developed foreign countries.

Short sales risk: If the price of securities sold short increases, the Fund would be required to pay more to replace the borrowed securities than the Fund received on the sale of the securities. Because there is theoretically no limit to the amount of the increase in price of the borrowed securities, the Fund’s risk of loss on a short sale is potentially unlimited.

Mortgage risk: Mortgage derivatives in the Fund’s portfolio may have especially volatile prices because the embedded leverage can magnify the impact of the extension or contraction event on the underlying cash flow. There may be a greater risk that the Fund could lose money due to prepayment and extension risks because the Fund invests heavily at times in mortgage-related securities.

High-yield risk: There is a greater risk that the Fund will lose money because it invests in high-yield bonds. These securities are considered speculative because they have a higher risk of issuer default, are subject to greater price volatility and may be illiquid.

Equities risk: The values of equity securities, such as preferred stocks, may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. They may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. Equity securities generally have greater price volatility than fixed income securities.

Leveraging risk: The Fund’s use of certain investments, such as derivative instruments or reverse repurchase agreements, and certain transactions, such as securities purchased on a when-issued, delayed delivery or forward commitment basis, can give rise to leverage within the Fund’s portfolio, which could cause the Fund’s returns to be more volatile than if leverage had not been used.

Market and Issuer risk: The value of securities owned by the Fund may go up or down, sometimes rapidly or unpredictably, due to factors affecting securities markets generally or particular industries. The value of a security may decline for a reason directly related to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods or services.

Liquidity risk: A particular investment may be difficult to purchase or sell and the Fund may be unable to sell illiquid securities at an advantageous time or price or achieve its desired level of exposure to a certain sector.

Risk Lose Money [Text]

rr_RiskLoseMoney

This means that you could lose money on your investment in the Fund or the Fund may not perform as well as other possible investments.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table show two aspects of the Fund: volatility and performance. The bar chart shows the volatility — or variability — of the Fund’s annual total returns over time, and shows that Fund performance can change from year to year. The table shows the Fund’s average annual total returns for certain time periods compared to the returns of a broad-based securities index. The bar chart and table provide some indication of the risks and potential rewards of investing in the Fund. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. To obtain updated performance information please visit the Fund’s website at www.harborfunds.com or call 800-422-1050.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart shows the volatility — or variability — of the Fund’s annual total returns over time, and shows that Fund performance can change from year to year. The table shows the Fund’s average annual total returns for certain time periods compared to the returns of a broad-based securities index.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-422-1050

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.harborfunds.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Calendar Year Total Returns for Institutional Class Shares

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

The Fund’s best and worst calendar quarters during this time period were:

	Total Return		Quarter/Year
Best Quarter		2.71%	3rd/2012
Worst Quarter		-1.29%	4th/2010

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns — As of December 31, 2012

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on a shareholder’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to shareholders who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax returns are shown for Institutional Class shares only. After-tax returns for the Administrative Class shares will vary.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to shareholders who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Class shares only. After-tax returns for the Administrative Class shares will vary.

Harbor Unconstrained Bond Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Management Fees

rr_ManagementFeesOverAssets

0.85%

Distribution and/or Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Interest Expense from Sale-Buyback Transactions

rr_Component1OtherExpensesOverAssets

0.02%

Other Operating Expenses

rr_Component2OtherExpensesOverAssets

0.58%

Other Expenses

rr_OtherExpensesOverAssets

0.60%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.45%

Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.38%

^[1]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_NetExpensesOverAssets

1.07%

^[1]

One Year

rr_ExpenseExampleYear01

109

Three Years

rr_ExpenseExampleYear03

421

Five Years

rr_ExpenseExampleYear05

756

Ten Years

rr_ExpenseExampleYear10

1,703

2011

rr_AnnualReturn2011

1.32%

2012

rr_AnnualReturn2012

8.00%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

2.71%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2010

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(1.29%)

One Year

rr_AverageAnnualReturnYear01

8.00%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

4.36%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 01, 2010

Harbor Unconstrained Bond Fund | Administrative Class

Risk/Return:

rr_RiskReturnAbstract

Management Fees

rr_ManagementFeesOverAssets

0.85%

Distribution and/or Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Interest Expense from Sale-Buyback Transactions

rr_Component1OtherExpensesOverAssets

0.02%

Other Operating Expenses

rr_Component2OtherExpensesOverAssets

0.58%

Other Expenses

rr_OtherExpensesOverAssets

0.60%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.70%

Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.38%

^[1]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_NetExpensesOverAssets

1.32%

^[1]

One Year

rr_ExpenseExampleYear01

134

Three Years

rr_ExpenseExampleYear03

499

Five Years

rr_ExpenseExampleYear05

887

Ten Years

rr_ExpenseExampleYear10

1,977

One Year

rr_AverageAnnualReturnYear01

7.81%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

4.11%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 01, 2010

Harbor Unconstrained Bond Fund | After Taxes on Distributions | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.02%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

3.49%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 01, 2010

Harbor Unconstrained Bond Fund | After Taxes on Distributions and Sale of Fund Shares | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.20%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

3.21%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 01, 2010

Harbor Unconstrained Bond Fund | BofA Merrill Lynch USD 3-Month LIBOR Constant Maturity (reflects no deduction for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

0.51%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

0.39%

Harbor Unconstrained Bond Fund | Barclays U.S. Aggregate Bond (reflects no deduction for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

4.22%

Five Years

rr_AverageAnnualReturnYear05

Ten Years

rr_AverageAnnualReturnYear10

Life of Fund

rr_AverageAnnualReturnSinceInception

6.08%

[1] The Adviser has contractually agreed to limit the Fund's operating expenses, excluding Interest Expense from Sale-Buyback Transactions, through February 28, 2014. Only the Board of Trustees may modify or terminate this agreement.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	HARBOR FUNDS
Prospectus Date	rr_ProspectusDate	Mar. 01, 2013
Document Creation Date	dei_DocumentCreationDate	Mar. 06, 2013