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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-01-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001041657</issuerCik>
        <issuerName>URBAN ONE, INC.</issuerName>
        <issuerTradingSymbol>UONE/UONEK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001175204</rptOwnerCik>
            <rptOwnerName>KANTOR DAVID M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1010 WAYNE AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>14TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>SILVER SPRING</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20910</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO, Radio Division</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

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            <transactionTimeliness>
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                <transactionPricePerShare>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
                    <value>436774</value>
                </sharesOwnedFollowingTransaction>
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                </directOrIndirectOwnership>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
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            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
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                </transactionShares>
                <transactionPricePerShare>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
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                </sharesOwnedFollowingTransaction>
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            <securityTitle>
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                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                </transactionAcquiredDisposedCode>
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                </sharesOwnedFollowingTransaction>
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        <nonDerivativeTransaction>
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                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
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                <transactionShares>
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                <transactionPricePerShare>
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                <sharesOwnedFollowingTransaction>
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                </sharesOwnedFollowingTransaction>
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                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class D Common Stock</value>
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                <transactionFormType>4</transactionFormType>
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    <derivativeTable>
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            <securityTitle>
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            <transactionDate>
                <value>2020-06-17</value>
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            <transactionCoding>
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                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>250981</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.15</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2015-11-05</value>
            </exerciseDate>
            <expirationDate>
                <value>2025-11-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class D Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>250981</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
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                <sharesOwnedFollowingTransaction>
                    <value>250981</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.04</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-06-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>49019</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.15</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2015-11-05</value>
            </exerciseDate>
            <expirationDate>
                <value>2025-11-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class D Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>49019</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>49019</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.9</value>
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            <transactionDate>
                <value>2020-06-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.15</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2017-08-07</value>
            </exerciseDate>
            <expirationDate>
                <value>2027-08-07</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class D Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.17</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-06-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>86774</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.15</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2019-07-05</value>
            </exerciseDate>
            <expirationDate>
                <value>2027-07-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class D Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>86774</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>86774</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">As reported in our Form 10-Q filed November 12, 2019, Form 10K filed April 29, 2020 and Form 10-Q filed represents a grant of restricted stock units under the Urban One, Inc. 2019 Equity and Other Incentive Plan.  The grants were effective June 12, 2019 and vested on January 6, 2020.  The grant was for 195,242 restricted shares of the Company's Class D common stock and the 139,084 represents the retained amounts after the withholding of 56,158 shares for taxes.</footnote>
        <footnote id="F2">All transactions previously reported on our Form 8-K filed June 17, 2020.</footnote>
        <footnote id="F3">The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions.  The reporting person undertakes to provide to Urban One, Inc., any security holder of Urban One, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this Form 4.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Karen Wishart, Attorney-In-Fact</signatureName>
        <signatureDate>2020-06-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
