<?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>0001726466</rptOwnerCik>
            <rptOwnerName>Kleffel Juliette</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 9012</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>STUART</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>34995</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>EVP, Chief Banking Officer</otherText>
        </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>5765</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>49155</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>640</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1464</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5290</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
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    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock Right to Buy</value>
                <footnoteId id="F5"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>31.15</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2028-04-02</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>12635</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12635</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock Right to Buy</value>
                <footnoteId id="F5"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>28.69</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2027-04-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>14831</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14831</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </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 31, 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, 2021, which shall vest over 3 years in one-third increments , beginning on April 1, 2022, and on each anniversary thereafter, subject to continued employment.</footnote>
        <footnote id="F3">Represents an unvested time-based restricted stock award granted on April 1, 2022, which shall vest over 3 years in one-third increments , beginning on 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, 2023, which shall vest over 3 years in one-third increments , beginning on April 1, 2024, and on each anniversary thereafter, subject to continued employment.</footnote>
        <footnote id="F5">Granted pursuant to Seacoast Banking Corporation of Florida's 2013 Incentive Plan.</footnote>
        <footnote id="F6">Vests over 3 years in one-third increments each anniversary of the date of grant beginning on the first anniversary of the date of grant (the date indicated), subject to continuous employment on each vesting date and the Company's banking subsidiary meets certain capital requirements.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kathy L. Hsu as Power of Attorney for Juliette Kleffel</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
0001726466
Kleffel Juliette
PO BOX 9012
STUART
FL
34995
0
0
0
1
EVP, Chief Banking Officer
0
Common Stock
2024-02-29
4
A
0
5765
0
A
49155
D
Common Stock
640
D
Common Stock
1464
D
Common Stock
5290
D
Common Stock Right to Buy
31.15
2028-04-02
Common Stock
12635
12635
D
Common Stock Right to Buy
28.69
2027-04-03
Common Stock
14831
14831
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 31, 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, 2021, which shall vest over 3 years in one-third increments , beginning on April 1, 2022, and on each anniversary thereafter, subject to continued employment.
Represents an unvested time-based restricted stock award granted on April 1, 2022, which shall vest over 3 years in one-third increments , beginning on April 1, 2023, and on each anniversary thereafter, subject to continued employment.
Represents an unvested time-based restricted stock award granted on April 1, 2023, which shall vest over 3 years in one-third increments , beginning on April 1, 2024, and on each anniversary thereafter, subject to continued employment.
Granted pursuant to Seacoast Banking Corporation of Florida's 2013 Incentive Plan.
Vests over 3 years in one-third increments each anniversary of the date of grant beginning on the first anniversary of the date of grant (the date indicated), subject to continuous employment on each vesting date and the Company's banking subsidiary meets certain capital requirements.
/s/ Kathy L. Hsu as Power of Attorney for Juliette Kleffel
2024-03-04