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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-06-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001748790</issuerCik>
        <issuerName>Amcor plc</issuerName>
        <issuerTradingSymbol>AMCR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001776117</rptOwnerCik>
            <rptOwnerName>Guerra Karen Jane</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>83 TOWER ROAD NORTH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WARMLEY, BRISTOL</rptOwnerCity>
            <rptOwnerState>X0</rptOwnerState>
            <rptOwnerZipCode>BS30 8XP</rptOwnerZipCode>
            <rptOwnerStateDescription>UNITED KINGDOM</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2019-06-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>46721</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>46721</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Traded as Chess Depository Interests (&quot;CDIs&quot;) on the Australian Stock Exchange (the &quot;ASX&quot;). CDIs represent a beneficial interests in one ordinary share of Amcor held by CHESS Depository Nominees Pty Ltd.</footnote>
        <footnote id="F2">On June 11, 2019, Amcor plc (&quot;Amcor&quot;) consummated the business combination (the &quot;Merger&quot;) pursuant to the Transaction Agreement dated August 6, 2018 (the &quot;Transaction Agreement&quot;) by and among Amcor plc (f/k/a Arctic Jersey Limited), Amcor Limited (&quot;Old Amcor&quot;), Arctic Corp. and Bemis Company, Inc. (&quot;Bemis&quot;), pursuant to which each of Bemis and Old Amcor were acquired by and became wholly-owned subsidiaries of Amcor in a stock-for-stock transaction. CDIs reported herein were received by the Reporting Person pursuant to the Transaction Agreement.</footnote>
        <footnote id="F3">Pursuant to the Transaction Agreement, each ordinary share of Old Amcor previously held by the Reporting Person was converted into one CDI of Amcor, or, at the election of the Reporting Person, one ordinary share of Amcor.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Damien Clayton, by power of attorney for Karen Guerra</signatureName>
        <signatureDate>2019-06-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
