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

    <schemaVersion>X0407</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-04-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001969559</rptOwnerCik>
            <rptOwnerName>Michaelis Nils</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>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President, COO, Head of M&amp;A</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Ordinary Shares</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-04-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>455</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>455</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>85312</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 Haller Bay Pte. Ltd. The Reporting Person may be deemed to beneficially own shares held by Haller Bay Pte. Ltd. by virtue of his control over Haller Bay Pte. Ltd. The Reporting Person disclaims beneficial ownership of Issuer's securities held by Haller Bay Pte. Ltd., except to the extent of his respective pecuniary interest.</footnote>
    </footnotes>

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