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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-12-08</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001387713</issuerCik>
        <issuerName>NEULION, INC.</issuerName>
        <issuerTradingSymbol>NLN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001084311</rptOwnerCik>
            <rptOwnerName>KRONFELD DAVID</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1600 OLD COUNTRY ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PLAINVIEW</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11803</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>130635</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>51000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.5</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1095300</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By DKB JTV Holdings, LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.48</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1109800</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By DKB JTV Holdings, LLC</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class 3 Preference Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7341715</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By JK&amp;B Capital V Special Opportunity Fund, L.P.</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class 3 Preference Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9732042</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By JK&amp;B Capital V, L.P.</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Multiple same-way open market purchases effected on the same day within a one dollar price range are reported on this line. The figure in the price column is the weighted average purchase price for these transactions. These trades were executed on the Toronto Stock Exchange, and the purchase prices were in Canadian dollars. The purchase price per share for each trade was Cdn$0.50.  The purchase prices were converted to US dollars at an exchange rate of 0.9899 by the executing broker, BMO Nesbitt Burns, upon the execution of the trades.</footnote>
        <footnote id="F2">This trade was executed on the Toronto Stock Exchange, and the purchase price was in Canadian dollars.  The purchase price was Cdn$0.48 per share.  The purchase price was converted to US dollars at an exchange rate of 0.9909 by the executing broker, BMO Nesbitt Burns, upon the execution of the trade.</footnote>
        <footnote id="F3">DKB JTV Holdings, LLC is a Delaware limited liability company that is controlled by Mr. Kronfeld.  The reporting person disclaims beneficial ownership of these Common Stock except to the extent of his pecuniary interest therein.  This report shall not be deemed an admission that the reporting person is the beneficial owner of all of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.</footnote>
        <footnote id="F4">JK&amp;B Capital V Special Opportunity Fund, L.P. is a Delaware limited partnership that is controlled by Mr. Kronfeld.  The reporting person disclaims beneficial ownership of these Preference Shares except to the extent of his pecuniary interest therein.  This report shall not be deemed an admission that the reporting person is the beneficial owner of all of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.</footnote>
        <footnote id="F5">JK&amp;B Capital V, L.P. is a Delaware limited partnership that is controlled by Mr. Kronfeld.  The reporting person disclaims beneficial ownership of these Preference Shares except to the extent of his pecuniary interest therein.  This report shall not be deemed an admission that the reporting person is the beneficial owner of all of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Roy E. Reichbach, attorney in fact</signatureName>
        <signatureDate>2010-12-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
