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<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-06-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001579910</issuerCik>
        <issuerName>Resonant Inc</issuerName>
        <issuerTradingSymbol>RESN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001438223</rptOwnerCik>
            <rptOwnerName>TIRVA ROBERT L.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RESONANT INC. 10900 STONELAKE BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 100, OFFICE 02-130</rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78759</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

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                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
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                <sharesOwnedFollowingTransaction>
                    <value>51472</value>
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                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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                <value>Common Stock</value>
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                </directOrIndirectOwnership>
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    <derivativeTable>
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            <expirationDate>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13736</value>
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                    <value>12712</value>
                </transactionShares>
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                    <value>0</value>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>12712</value>
                </underlyingSecurityShares>
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                    <value>12711</value>
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            <securityTitle>
                <value>Restricted Stock Units</value>
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            <conversionOrExercisePrice>
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            <transactionDate>
                <value>2021-06-08</value>
            </transactionDate>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
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            <transactionAmounts>
                <transactionShares>
                    <value>19788</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
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                    <value>A</value>
                </transactionAcquiredDisposedCode>
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            <exerciseDate>
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            <expirationDate>
                <footnoteId id="F4"/>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>19788</value>
                </underlyingSecurityShares>
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                <sharesOwnedFollowingTransaction>
                    <value>19788</value>
                </sharesOwnedFollowingTransaction>
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        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of Resonant Inc. common stock.</footnote>
        <footnote id="F2">50% of the shares vested on June 8, 2020, and 50% of the shares vested on June 7, 2021.</footnote>
        <footnote id="F3">50% of the shares vested on June 7, 2021, and the remaining 50% of the shares shall vest on the earlier of (i) the day prior to the second annual meeting of the stockholders following the grant and (ii) June 9, 2022.</footnote>
        <footnote id="F4">50% of the shares shall vest on the earlier of (i) the day prior to the first annual meeting of stockholders following the grant and (ii) June 8, 2022, and 50% of the shares shall vest on the earlier of (i) the day prior to the second annual meeting of stockholders following the grant and (ii) June 8, 2023.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Martin S. McDermut, Attorney-In-Fact</signatureName>
        <signatureDate>2021-06-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
