<SEC-DOCUMENT>0001567619-18-002214.txt : 20180906
<SEC-HEADER>0001567619-18-002214.hdr.sgml : 20180906
<ACCEPTANCE-DATETIME>20180906174927
ACCESSION NUMBER:		0001567619-18-002214
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180904
FILED AS OF DATE:		20180906
DATE AS OF CHANGE:		20180906

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Fanning Quinn P
		CENTRAL INDEX KEY:			0001441735

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06311
		FILM NUMBER:		181058468

	MAIL ADDRESS:	
		STREET 1:		C/O TIDEWATER INC
		STREET 2:		601 POYDRAS ST, STE 1900
		CITY:			NEW ORLEANS
		STATE:			LA
		ZIP:			70130

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TIDEWATER INC
		CENTRAL INDEX KEY:			0000098222
		STANDARD INDUSTRIAL CLASSIFICATION:	WATER TRANSPORTATION [4400]
		IRS NUMBER:				720487776
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6002 ROGERDALE ROAD
		STREET 2:		SUITE 600
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77072
		BUSINESS PHONE:		7134705300

	MAIL ADDRESS:	
		STREET 1:		6002 ROGERDALE ROAD
		STREET 2:		SUITE 600
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77072

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TIDEWATER MARINE SERVICE INC
		DATE OF NAME CHANGE:	19780724
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-09-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000098222</issuerCik>
        <issuerName>TIDEWATER INC</issuerName>
        <issuerTradingSymbol>TDW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001441735</rptOwnerCik>
            <rptOwnerName>Fanning Quinn P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O TIDEWATER INC.</rptOwnerStreet1>
            <rptOwnerStreet2>6002 ROGERDALE ROAD, SUITE 600</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77072</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP &amp; CFO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-09-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>16423</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.000</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>153600</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-09-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>153400</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>52</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by 401(k) Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported represents the weighted average price of the shares sold. Shares were sold at varying prices in the range of $32.000 - $32.015. The Reporting Person hereby undertakes, upon request of the Staff of the U.S. Securities and Exchange Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Bruce D. Lundstrom as Agent and Attorney-in-Fact for Quinn P. Fanning</signatureName>
        <signatureDate>2018-09-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
