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

    <schemaVersion>X0407</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-04-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001865045</issuerCik>
        <issuerName>FAT PROJECTS ACQUISITION CORP</issuerName>
        <issuerTradingSymbol>FATP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001969552</rptOwnerCik>
            <rptOwnerName>Lo Tristan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>27 BUKIT MANIS ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SENTOSA GOLF CLUB</rptOwnerStreet2>
            <rptOwnerCity>SINGAPORE</rptOwnerCity>
            <rptOwnerState>U0</rptOwnerState>
            <rptOwnerZipCode>099892</rptOwnerZipCode>
            <rptOwnerStateDescription>SINGAPORE</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Co-Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Ordinary Shares</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-04-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4198</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Ordinary Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4198</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>783302</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Class B ordinary shares have no expiration date and will automatically convert into Class A ordinary shares at the time of the Issuer's initial business combination on a one-for-one basis, subject to adjustment as set forth in the issuer's registration statement on Form S-1 (File No. 333-257126).</footnote>
        <footnote id="F2">The Class B ordinary shares were transferred without consideration to one or more purchasers of non-interest-bearing and/or 15% interest-bearing notes issued by Issuer to incentivize the note purchaser(s) to purchase the note(s).</footnote>
        <footnote id="F3">The securities are held directly by Fat Projects International Investments and Holdings Limited. The Reporting Person may be deemed to beneficially own shares held by Fat Projects International Investments and Holdings Limited by virtue of his control over Fat Projects International Investments and Holdings Limited. The Reporting Person disclaims beneficial ownership of Issuer's securities held by Fat Projects International Investments and Holdings Limited., except to the extent of his pecuniary interest.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Tristan Lo, By Nelson Mullins Riley &amp; Scarborough through power of Attorney</signatureName>
        <signatureDate>2023-05-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
