-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Vr1lJYMgu8eBv6L4cKbgQQjwMT/PUEGEBCdalJYqjAEFFICGzjbqFrUCJ7LQhuIn
 /C6WzU9BxDBygSi7Fh3Jgg==

<SEC-DOCUMENT>0001140361-10-025966.txt : 20100617
<SEC-HEADER>0001140361-10-025966.hdr.sgml : 20100617
<ACCEPTANCE-DATETIME>20100617174313
ACCESSION NUMBER:		0001140361-10-025966
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100615
FILED AS OF DATE:		20100617
DATE AS OF CHANGE:		20100617

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GORDON SHELDON S
		CENTRAL INDEX KEY:			0001190196

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33607
		FILM NUMBER:		10904183

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GULFMARK OFFSHORE INC
		CENTRAL INDEX KEY:			0001030749
		STANDARD INDUSTRIAL CLASSIFICATION:	OIL & GAS FILED MACHINERY & EQUIPMENT [3533]
		IRS NUMBER:				760526032
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		10111 RICHMOND AVE
		STREET 2:		STE 340
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77042
		BUSINESS PHONE:		7139639522

	MAIL ADDRESS:	
		STREET 1:		10111 RICHMOND AVE
		STREET 2:		STE 340
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77042
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-06-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001030749</issuerCik>
        <issuerName>GULFMARK OFFSHORE INC</issuerName>
        <issuerTradingSymbol>GLF</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001190196</rptOwnerCik>
            <rptOwnerName>GORDON SHELDON S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10111 RICHMOND AVE, STE.340</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77042</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>PHANTOM STOCK</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-06-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>258.14</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>26.73</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>258.14</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>23628.14</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Phantom Stock units credited under the Company's Executive Nonqualified Excess Plan (the &quot;Plan&quot;). Participants are always 100% vested in their contributions to the Plan. Employer contributions vest according to the provision of the Plan, which is generally based on years of service (20% per year of credited service). A participant is 100% vested after 5 years of credited service.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Sheldon Gordon</signatureName>
        <signatureDate>2010-06-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----