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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2024-12-09</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0002039058</issuerCik>
        <issuerName>Jackson Acquisition Co II</issuerName>
        <issuerTradingSymbol>JACS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001985175</rptOwnerCik>
            <rptOwnerName>Ayers James Nicholas</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O JACKSON ACQUISITION COMPANY II</rptOwnerStreet1>
            <rptOwnerStreet2>2655 NORTHWINDS PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>ALPHARETTA</rptOwnerCity>
            <rptOwnerState>GA</rptOwnerState>
            <rptOwnerZipCode>30009</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Class B ordinary shares</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A ordinary shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">As described in Issuer's Registration Statement on Form S-1 (File No. 333-282393), as amended, the Class B ordinary shares, par value $0.0001 per share, of the Issuer will automatically convert into Class A ordinary shares, par value $0.0001 per share, of the Issuer at the time of a qualifying initial business combination, or earlier at the option of the holder, on a one-for-one basis, subject to certain adjustments, and have no expiration date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Nelson Mullins Riley &amp; Scarborough LLP, Attorney-in-Fact</signatureName>
        <signatureDate>2024-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
