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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-02-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001529864</issuerCik>
        <issuerName>Enova International, Inc.</issuerName>
        <issuerTradingSymbol>ENVA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001575452</rptOwnerCik>
            <rptOwnerName>Cunningham Steven E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ENOVA INTERNATIONAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>175 W. JACKSON BOULEVARD, SUITE 1000</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60604</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock, par value $0.00001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2019-02-13</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1260</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>77488</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This transaction represents the withholding by Enova International, Inc. (&quot;Issuer&quot;) of Issuer's shares to pay taxes in connection with the vesting of restricted stock on February 13, 2019. The timing and amount of the transaction were determined by the terms of the applicable restricted stock and were not within the control of Mr. Cunningham.</footnote>
        <footnote id="F2">Includes a grant of RSUs that have vested and shall vest in substantially equal one-third increments on each of the following dates as long as grantee serves as an employee of Issuer or an affiliate thereof through the applicable vesting date: February 23, 2017, February 23, 2018 and February 23, 2019.</footnote>
        <footnote id="F3">Includes a grant of RSUs that shall vest in substantially equal one-fourth increments on each of the following dates as long as grantee serves as an employee of Issuer or an affiliate thereof through the applicable vesting date: February 17, 2018, February 17, 2019, February 17, 2020 and February 17, 2021.</footnote>
        <footnote id="F4">Includes a grant of RSUs that shall vest in substantially equal one-fourth increments on each of the following dates as long as grantee serves as an employee of Issuer or an affiliate thereof through the applicable vesting date: February 13, 2019, February 13, 2020, February 13, 2021 and February 13, 2022.</footnote>
        <footnote id="F5">Includes a grant of RSUs that shall vest in substantially equal one-fourth increments on each of the following dates as long as grantee serves as an employee of Issuer or an affiliate thereof through the applicable vesting date: June 22, 2019.</footnote>
        <footnote id="F6">Since the date of the Mr. Cunningham's last ownership report, he transferred 58967 RSUs and 48552 NQSOs to his ex-wife pursuant to a domestic relations order.  The reporting person no longer reports as beneficially owned any securities owned by his ex-wife.</footnote>
        <footnote id="F7">The number of NQSOs Mr. Cunningham has left is 72824.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Sean Rahilly, attorney-in-fact</signatureName>
        <signatureDate>2019-02-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
