BOLT: Coastlands Capital LP reported buying shares

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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-11-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001641281</issuerCik>
        <issuerName>Bolt Biotherapeutics, Inc.</issuerName>
        <issuerTradingSymbol>BOLT</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002068530</rptOwnerCik>
            <rptOwnerName>Coastlands Capital LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>601 CALIFORNIA STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1210</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94108</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-11-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.38</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>462416</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Coastlands Capital LP</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported represents the weighted average purchase price per share. The shares were purchased in multiple transactions at prices ranging from $6.3618 to $6.4044. Upon request by the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer, the reporting persons will provide full information regarding the number of shares purchased at each separate price.</footnote>
        <footnote id="F2">Coastlands Capital LP (&quot;Coastlands&quot;) and Coastlands Capital GP LLC (the &quot;General Partner&quot;) are the investment adviser and general partner, respectively, of Coastlands Capital Partners LP, a Delaware limited partnership (the &quot;Partnership&quot;). Coastlands Capital LLC (&quot;Coastlands GP&quot;) is the general partner of Coastlands. Matthew Perry is the control person of Coastlands, the Partnership, Coastlands GP and the General Partner. The reporting persons are filing this Form 4 jointly, but not as members of a group, and each disclaims membership in a group. Each reporting person also disclaims beneficial ownership of common stock except to the extent of that person's pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Mark Shamia, Chief Operating Officer of the General Partner of Coastlands Capital LP</signatureName>
        <signatureDate>2026-11-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Mark Shamia, Chief Operating Officer of the General Partner of Coastlands Capital Partners LP</signatureName>
        <signatureDate>2026-11-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Mark Shamia, Chief Operating Officer of Coastlands Capital GP LLC</signatureName>
        <signatureDate>2026-11-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Mark Shamia, Chief Operating Officer of Coastlands Capital LLC</signatureName>
        <signatureDate>2026-11-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Matthew D. Perry</signatureName>
        <signatureDate>2026-11-10</signatureDate>
    </ownerSignature>
</ownershipDocument>