<?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>0001525504</rptOwnerCik>
            <rptOwnerName>Long Nicholas T.</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>
            </securityTitle>
            <transactionDate>
                <value>2019-06-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">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. Shares reported herein were received by the Reporting Person pursuant to the Transaction Agreement.</footnote>
        <footnote id="F2">Pursuant to the Transaction Agreement, each American depositary receipt (the &quot;ADRs&quot;) evidencing American depositary shares previously held by the Reporting Person was converted into four ordinary shares of Amcor.</footnote>
    </footnotes>

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