<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001110507</issuerCik>
        <issuerName>ESCHELON TELECOM INC</issuerName>
        <issuerTradingSymbol>ESCH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001294921</rptOwnerCik>
            <rptOwnerName>Smith Richard Allen Jr</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>730 SECOND AVENUE SOUTH</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 900</rptOwnerStreet2>
            <rptOwnerCity>MINNEAPOLIS</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55402</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO &amp; President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Options</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>12.19</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>25000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.19</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2005-08-18</value>
            </exerciseDate>
            <expirationDate>
                <value>2015-08-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>25000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>290313</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On February 6, 2003, Mr. Smith was granted options to purchase 168,530 shares of common stock.  119,721 shares are fully vested with the remaining 48,809 shares vesting in equal installments beginning on February 7, 2006.  On May 22, 2003, Mr. Smith was granted options to purchase 14,762 shares of common stock, with 20% of the options vesting on the grant date and the remaining shares vesting 20% on each subsequent anniversary of the grant date. On May 20, 2004, Mr. Smith was granted options to purchase 11,071 shares of common stock, with 20% of the options vesting on the grant date and the remaining shares vesting 20% on each subsequent anniversary of the grant date.</footnote>
        <footnote id="F2">On April 1, 2005, Mr. Smith was granted options to purchase 5,536 shares of common stock, with 20% of the options vesting on the grant date and the remaining shares vesting 20% on each subsequent anniversary of the grant date. On April 29, 2005, Mr. Smith was granted options to purchase 65,414 shares of common stock, with 33 1/3% of the options vesting on the grant date and the remaining shares vesting 33 1/3% on each subsequent anniversary of the grant date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Richard Allen Smith Jr</signatureName>
        <signatureDate>2005-08-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
