<SEC-DOCUMENT>0001137789-18-000084.txt : 20181022
<SEC-HEADER>0001137789-18-000084.hdr.sgml : 20181022
<ACCEPTANCE-DATETIME>20181022181105
ACCESSION NUMBER:		0001137789-18-000084
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20181018
FILED AS OF DATE:		20181022
DATE AS OF CHANGE:		20181022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PARK CHONG SUP
		CENTRAL INDEX KEY:			0001216771

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31560
		FILM NUMBER:		181132989

	MAIL ADDRESS:	
		STREET 1:		22071 DORSEY WAY
		CITY:			SARATOGA
		STATE:			CA
		ZIP:			95070

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Seagate Technology plc
		CENTRAL INDEX KEY:			0001137789
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER STORAGE DEVICES [3572]
		IRS NUMBER:				980648577
		STATE OF INCORPORATION:			L2
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		38/39 FITZWILLIAM SQUARE
		CITY:			DUBLIN 2
		STATE:			L2
		ZIP:			00000
		BUSINESS PHONE:		(353) (1) 234-3136

	MAIL ADDRESS:	
		STREET 1:		38/39 FITZWILLIAM SQUARE
		CITY:			DUBLIN 2
		STATE:			L2
		ZIP:			00000

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Seagate Technology
		DATE OF NAME CHANGE:	20090330

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SEAGATE TECHNOLOGY
		DATE OF NAME CHANGE:	20021212

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SEAGATE TECHNOLOGY HOLDINGS
		DATE OF NAME CHANGE:	20010406
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_154024624972738.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-10-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001137789</issuerCik>
        <issuerName>Seagate Technology plc</issuerName>
        <issuerTradingSymbol>STX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001216771</rptOwnerCik>
            <rptOwnerName>PARK CHONG SUP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>SEAGATE TECHNOLOGY PLC</rptOwnerStreet1>
            <rptOwnerStreet2>10200 S. DE ANZA BOULEVARD</rptOwnerStreet2>
            <rptOwnerCity>CUPERTINO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95014</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>Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2018-10-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8094</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>16809</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2018-10-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2914</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.76</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>32527</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>The Park Family Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Share Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-10-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8094</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Ordinary Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8094.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These Ordinary Shares are withheld securities to cover tax liabilities incident to the vesting of Restricted Share Units (&quot;RSUs&quot;).</footnote>
        <footnote id="F2">On October 19, 2018, the Reporting Person transferred 5,180 Ordinary Shares previously owned directly (8,094 Ordinary Shares vested on October 18, 2018 minus 2,914 Ordinary Shares withheld to cover tax liabilities) to The Park Family Trust.  The total of 32,527 shares held by The Park Family Trust also reflects a transfer of 8,715 Ordinary Shares, previously reported as directly owned by the Reporting Person, to The Park Family Trust.</footnote>
        <footnote id="F3">Each RSU represents a contingent right to receive one Ordinary Share of the Issuer.  This award vested one year from the date of grant.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jolene A. Mendelsohn Attorney-in-Fact for Chong Sup Park</signatureName>
        <signatureDate>2018-10-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
