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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-02-17</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>0</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>2019-02-17</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1272</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.71</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>76216</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </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 17, 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 or 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="F3">Includes a grant of RSUs that have vested or 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="F4">Includes a grant of RSUs that have vested or 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, 2017, June 22, 2018, June 22, 2019, and and June 22, 2020.</footnote>
        <footnote id="F5">The February 15, 2019 Form 4 filing for Mr. Cunningham erroneously included a reference to a grant of RSUs that have vested or shall vest on February 23, 2017, February 23, 2018, and February 23, 2019.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Sean Rahilly, attorney-in-fact</signatureName>
        <signatureDate>2019-02-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
