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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-08-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001581760</issuerCik>
        <issuerName>Life360, Inc.</issuerName>
        <issuerTradingSymbol>LIF</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001932661</rptOwnerCik>
            <rptOwnerName>Synge James</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O LIFE360, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1900 SOUTH NORFOLK STREET, SUITE 310</rptOwnerStreet2>
            <rptOwnerCity>SAN MATEO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94403</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>2026-08-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5833</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>45.05</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>219160</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-08-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>27466</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>44.31</value>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>191694</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The sale being reported on this Form 4 is the sale of Chess Depositary Interests (&quot;CDIs&quot;) as converted on a 1:3 common stock to CDI ratio. The CDIs were traded on the Australian Securities Exchange (the &quot;ASX&quot;) and were held by CHESS Depositary Nominees Pty, Limited, a subsidiary of ASX Limited, the company that operates the ASX.</footnote>
        <footnote id="F2">Reflects the number of common stock equivalent shares underlying the CDIs sold on the ASX.</footnote>
        <footnote id="F3">Reflects the weighted average sale price of the CDIs sold, as converted to USD by multiplying the amount by 3, based on the 3:1 conversion ratio for CDIs to common stock, and then multiplying by the exchange rate of 0.715 in effect at the time of the sale as published by the Reserve Bank of Australia.</footnote>
        <footnote id="F4">Includes 4,600 RSUs, each of which represents a contingent right to receive one share of the Issuer's common stock upon vesting.</footnote>
        <footnote id="F5">Includes common stock and the number of shares of common stock underlying CDIs as converted on a 1:3 common stock to CDI ratio.</footnote>
        <footnote id="F6">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $44.169 to $44.557, inclusive, per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote 3.</footnote>
        <footnote id="F7">Reflects the weighted average sale price of the CDIs sold, as converted to USD by multiplying the amount by 3, based on the 3:1 conversion ratio for CDIs to common stock, and then multiplying by the exchange rate of 0.7182 in effect at the time of the sale as published by the Reserve Bank of Australia.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jay Sood, as Attorney-in-Fact</signatureName>
        <signatureDate>2026-08-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
