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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-02-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001963479</rptOwnerCik>
            <rptOwnerName>Carroll Austen</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 9012</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>STUART</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34995</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Chief Lending Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-02-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5242</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>16870</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5290</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2439</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>582</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares subject to performance based restricted stock units (&quot;PSUs&quot;) granted on April 1, 2021, that were subject to performance requirements which were attained over a period ending December 23, 2023.  On February 29, 2024, the Company's Compensation and Governance Committee certified the number of shares attained based on the performance criteria, which will vest on December 31, 2024, provided the recipient remains in continuous service with the Company on the vesting date.</footnote>
        <footnote id="F2">Represents an unvested time-based restricted stock award granted on April 1 2023, which shall vest over 3 years in one-third increments, beginning April 1, 2024, and on each anniversary thereafter, subject to continued employment.</footnote>
        <footnote id="F3">Represents an unvested time-based restricted stock grant on April 1, 2022, which shall vest over 3 years in on-third increments, beginning April 1, 2023, and on each anniversary thereafter, subject to continued employment.</footnote>
        <footnote id="F4">Represents an unvested time-based restricted stock award granted on April 1, 2021, which shall vest over 3 years in one-third 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 Austen Carroll</signatureName>
        <signatureDate>2024-03-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2024-02-29
0
0000730708
SEACOAST BANKING CORP OF FLORIDA
SBCF
0001963479
Carroll Austen
P.O. BOX 9012
STUART
FL
34995
0
1
0
0
EVP, Chief Lending Officer
0
Common Stock
2024-02-29
4
A
0
5242
0
A
16870
D
Common Stock
5290
D
Common Stock
2439
D
Common Stock
582
D
Represents shares subject to performance based restricted stock units ("PSUs") granted on April 1, 2021, that were subject to performance requirements which were attained over a period ending December 23, 2023.  On February 29, 2024, the Company's Compensation and Governance Committee certified the number of shares attained based on the performance criteria, which will vest on December 31, 2024, provided the recipient remains in continuous service with the Company on the vesting date.
Represents an unvested time-based restricted stock award granted on April 1 2023, which shall vest over 3 years in one-third increments, beginning April 1, 2024, and on each anniversary thereafter, subject to continued employment.
Represents an unvested time-based restricted stock grant on April 1, 2022, which shall vest over 3 years in on-third increments, beginning April 1, 2023, and on each anniversary thereafter, subject to continued employment.
Represents an unvested time-based restricted stock award granted on April 1, 2021, which shall vest over 3 years in one-third increments, beginning April 1, 2022, and on each anniversary thereafter, subject to continued employment.
/s/ Kathy L. Hsu as Power of Attorney for Austen Carroll
2024-03-04