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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-04-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001810997</issuerCik>
        <issuerName>XPENG INC.</issuerName>
        <issuerTradingSymbol>XPEV</issuerTradingSymbol>
        <issuerForeignTradingSymbol>09868.HK</issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001975936</rptOwnerCik>
            <rptOwnerName>Wang Fengying</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>NO.10, CENCUN FENGZHUANG AVENUE,</rptOwnerStreet1>
            <rptOwnerStreet2>TIANHE DISTRICT</rptOwnerStreet2>
            <rptOwnerCity>GUANGZHOU</rptOwnerCity>
            <rptOwnerNonUSStateTerritory>CHINA</rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>F4</rptOwnerCountry>
            <rptOwnerZipCode>510640</rptOwnerZipCode>
            <rptOwnerStateDescription>CHINA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A ordinary shares</value>
            </securityTitle>
            <transactionDate>
                <value>2026-04-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>600000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1650000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Share Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-04-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>600000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A ordinary shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>600000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>600000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Issuer's Class A ordinary shares were issued to the reporting person upon vesting of Restricted Share Units (RSUs) on April 1, 2026.</footnote>
        <footnote id="F2">The reporting person was granted an aggregate of 2,400,000 RSUs under the 2019 Equity Incentive Plan on March 24, 2023. Upon vesting of the applicable RSUs, the grantee shall be entitled to receive the same amount of Class A ordinary shares of the Company with nil purchase price. The RSUs subject to the award shall vest in four equal annual installments on each anniversary of the vesting commencement date, April 1, 2023, subject to the reporting person's continued service and the achievement of individual performance targets. Therefore, 600,000 RSUs subject to this award vested on April 1, 2026, and the remaining 600,000 RSUs subject to this award are scheduled to vest on April 1, 2027.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Wang Fengying</signatureName>
        <signatureDate>2026-04-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
