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

    <schemaVersion>X0607</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2026-03-18</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001767582</issuerCik>
        <issuerName>Luckin Coffee Inc.</issuerName>
        <issuerTradingSymbol>LKNCY</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002013724</rptOwnerCik>
            <rptOwnerName>Getz Joel A</rptOwnerName>
        </reportingOwnerId>
    <reportingOwnerAddress>
      <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
      <rptOwnerStreet1>28TH FL, BUILDING T3, HAIXI JINGU PLAZA</rptOwnerStreet1>
      <rptOwnerStreet2>1-3 TAIBEI ROAD, SIMING DISTRICT</rptOwnerStreet2>
      <rptOwnerCity>XIAMEN</rptOwnerCity>
      <rptOwnerState></rptOwnerState>
      <rptOwnerCountry>F4</rptOwnerCountry>
      <rptOwnerZipCode>361008</rptOwnerZipCode>
      </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>American Depositary Shares</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30576</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Restricted Share Units</value>
                <footnoteId id="F2"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8770</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Each American Depositary Share (&quot;ADS&quot;) represents eight Class A Ordinary Shares.</footnote>
        <footnote id="F2">Each restricted share unit represents a contingent right to receive one ADS. The restricted share units will vest on December 31, 2026 with no conversion or exercise price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Joel A. Getz</signatureName>
        <signatureDate>2026-03-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
