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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-07-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001166789</issuerCik>
        <issuerName>LIN TV CORP</issuerName>
        <issuerTradingSymbol>TVL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001231113</rptOwnerCik>
            <rptOwnerName>PARENT DENISE M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O LIN TV CORP</rptOwnerStreet1>
            <rptOwnerStreet2>FOUR RICHMOND SQUARE</rptOwnerStreet2>
            <rptOwnerCity>PROVIDENCE</rptOwnerCity>
            <rptOwnerState>RI</rptOwnerState>
            <rptOwnerZipCode>02906</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP General Counsel &amp; Secretary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-07-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>720</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.2849</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>79976</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Sold pursuant to a 10b5-1 plan.</footnote>
        <footnote id="F2">The sale price represents the weighted average sale price of individual sales totaling 720 in the aggregate.  The transactions occurred at prices in the range of $1.26 per share to $1.30 per share.  Upon request from the Securities and Exchange Commission or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price will be made available.</footnote>
        <footnote id="F3">This number includes 47,676 restricted shares awarded pursuant to the 2002 Amended and Restated Stock Plan.  These shares remain subject to forfeiture and are non-transferable until vested.  The shares vest over five years from the date of grant.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Nicholas N. Mohamed, Attorney-in-fact for Denise M. Parent</signatureName>
        <signatureDate>2009-07-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
