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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-02-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001315224</rptOwnerCik>
            <rptOwnerName>Fisher David</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>CEO &amp; President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock, par value $0.00001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2018-02-13</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>84388</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>406968</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock option (right to buy) with limited SAR</value>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>20.85</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-02-13</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>188585</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <value>2025-02-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common stock, par value $0.00001 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>188585</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>936403</value>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This transaction reflects a grant of Restricted Stock Units (&quot;RSUs&quot;) that shall vest in substantially equal one-fourth increments on each of the following dates as long as grantee serves as an employee of Enova International, Inc. (&quot;Issuer&quot;) or an affiliate thereof through the applicable vesting date: February 13, 2019, February 13, 2020, February 13, 2021 and Febuary 13, 2022.</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: December 13, 2015, December 13, 2016, December 13, 2017 and December 13, 2018.</footnote>
        <footnote id="F3">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="F4">Includes a grant of RSUs that shall vest in substantially equal one-foruth 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="F5">The limited stock appreciation right (&quot;SAR&quot;) and employee stock option were granted in tandem. Accordingly, the exercise of one results in the expiration of the other. The SAR may be exercised only during the period beginning on the first day following the date that a &quot;Change in Control&quot; of Issuer occurs (as defined in the related grant agreement) and ending on the thirtieth day following such date. Upon exercise, the grantee shall be able to receive an amount equal to the product computed by multiplying (i) the excess of the &quot;Offer Value Per Share&quot; over the exercise price of the underlying option by (ii) the number of shares with respect to which the SAR is being exercised; provided, that such amount shall only be payable in the event an &quot;Offer&quot; is made.</footnote>
        <footnote id="F6">The &quot;Offer Value Per Share&quot; means the average selling price of Issuer's common stock during the period of 30 days ending on the date on which the SAR is exercised. &quot;Offer&quot; means any tender offer or exchange offer for outstanding shares of Issuer representing at least 30% of the total voting power of the stock of Issuer, or an offer to purchase assets from Issuer that have a total gross fair market value equal to or more than 40% of the total gross fair market value of all of the assets of Issuer, other than an offer made by Issuer.</footnote>
        <footnote id="F7">The options 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 13, 2019, February 13, 2020 and February 13, 2021.</footnote>
        <footnote id="F8">Includes a grant of options that have vested or 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: December 13, 2016, December 13, 2017 and December 13, 2018.</footnote>
        <footnote id="F9">Includes a grant of options that have vested or 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="F10">Includes a grant of options that 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 17, 2018, February 17, 2019 and February 17, 2020.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Lisa M. Young, attorney-in-fact</signatureName>
        <signatureDate>2018-02-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
