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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-07-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000730708</issuerCik>
        <issuerName>SEACOAST BANKING CORP OF FLORIDA</issuerName>
        <issuerTradingSymbol>SBCF</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001987247</rptOwnerCik>
            <rptOwnerName>SHEAROUSE JOSEPH B III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 9012</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>STUART</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34995</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-07-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2529</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.71</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>36007</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1397</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>40</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Shares held by spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Stock issued form Seacoast's 2021 Incentive Plan for Board service in 2023</footnote>
        <footnote id="F2">Represents an unvested time-based restricted stock award granted April 1, 2021, which shall vest in three year increments, beginning April 1, 2022, and on each anniversary, thereafter, subject to continued employment.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kathy L. Hsu as Power of Attorney for Joseph B. Shearouse, III</signatureName>
        <signatureDate>2023-08-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2023-07-31
0
0000730708
SEACOAST BANKING CORP OF FLORIDA
SBCF
0001987247
SHEAROUSE JOSEPH B III
PO BOX 9012
STUART
FL
34995
1
0
0
0
0
Common Stock
2023-07-31
4
A
0
2529
24.71
A
36007
D
Common Stock
1397
D
Common Stock
40
I
Shares held by spouse
Stock issued form Seacoast's 2021 Incentive Plan for Board service in 2023
Represents an unvested time-based restricted stock award granted April 1, 2021, which shall vest in three year increments, beginning April 1, 2022, and on each anniversary, thereafter, subject to continued employment.
/s/ Kathy L. Hsu as Power of Attorney for Joseph B. Shearouse, III
2023-08-02