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

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-08-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001361983</issuerCik>
        <issuerName>ORBCOMM Inc.</issuerName>
        <issuerTradingSymbol>ORBC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001379722</rptOwnerCik>
            <rptOwnerName>Kelleher Timothy</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ORBCOMM INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2115 LINWOOD AVENUE, SUITE 100</rptOwnerStreet2>
            <rptOwnerCity>FORT LEE</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07024</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-08-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2.2015</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>18215</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Restricted Stock Unit (Time Vested)</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4116383</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by KMCP Satellite Investments LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.20 to $2.207, inclusive.</footnote>
        <footnote id="F2">The reporting person undertakes to provide to the Company, any security holder of the Company, 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 footnote (1) to this Form 4.</footnote>
        <footnote id="F3">Each time vested Restricted Stock Unit (&quot;RSU&quot;) represents the right to receive one share of common stock. The number of RSUs was determined by dividing $30,000 by the closing price of ORBCOMM Inc. (the &quot;Company&quot;) common stock on February 1, 2011 of $3.00 per share. The RSUs vest on January 1, 2012.</footnote>
        <footnote id="F4">The managing member of KMCP Satellite Investments LLC (formerly PCG Satellite Investments LLC) is CalPERS Corporate Partners, LLC, whose manager is KMCP Advisors II LLC. Timothy Kelleher is a Managing Partner of KMCP Advisors II LLC, which is an affiliate of KMCP Satellite Investments LLC. Mr. Kelleher disclaims beneficial ownership of the shares held by KMCP Satellite Investments LLC except to the extent of his pecuniary interest therein. On August 19, 2011, Mr. Douglas Meltzer, a Managing Partner of KMCP Advisors II LLC, made open market purchases of 5,000 shares of ORBCOMM Inc. common stock at a weighted average price of $2.1877 per share through a family trust.  Mr. Meltzer's shares are not attributed to KMCP Satellite Investments LLC, CalPERS Corporate Partners, LLC, KMCP Advisors II LLC or Mr. Kelleher and each of the foregoing disclaims beneficial ownership of the shares held by Mr. Meltzer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Christian Le Brun, by power of attorney</signatureName>
        <signatureDate>2011-08-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
