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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-07-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000828146</issuerCik>
        <issuerName>INTERLINK ELECTRONICS INC</issuerName>
        <issuerTradingSymbol>LINK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001349005</rptOwnerCik>
            <rptOwnerName>Becker Steven R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 CRESCENT COURT</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrants</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.51</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-07-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>359920</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2007-07-20</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-07-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>359920</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>359920</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Limited Partnerships</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>8% Convertible Notes</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.26</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-07-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>907000</value>
                    <footnoteId id="F2"/>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>907000</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2007-07-20</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-07-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>719841</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>719841</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Limited Partnerships</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents warrants held directly by SRB Greenway Capital, L.P. (&quot;LP&quot;), SRB Greenway Capital (QP, L.P. (&quot;QP&quot;) and SRB Greenway Offshore Operating Fund, L.P. (&quot;Offshore&quot;).  LP directly holds a warrant exercisable for 35,873 shares of common stock, QP directly holds a warrant exercisable for 311,071 shares of common stock and Offshore holds a warrant exercisable for 12,976 shares of common stock.  The reporting person disclaims beneficial ownership in the securities directly held by LP, QP and Offshore, except to the extent of his pecuniary interest.</footnote>
        <footnote id="F2">Represents convertible notes held directly by SRB Greenway Capital, L.P. (&quot;LP&quot;), SRB Greenway Capital (QP, L.P. (&quot;QP&quot;) and SRB Greenway Offshore Operating Fund, L.P. (&quot;Offshore&quot;).  LP directly holds a convertible note convertible into 71,746 shares of common stock, QP directly holds a convertible note convertible into 622,143 shares of common stock and Offshore holds a convertible note convertible into 25,952 shares of common stock.  The reporting person disclaims beneficial ownership in the securities directly held by LP, QP and Offshore, except to the extent of his pecuniary interest.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Steven R. Becker</signatureName>
        <signatureDate>2007-07-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
