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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2021-10-01</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001635088</issuerCik>
        <issuerName>Roivant Sciences Ltd.</issuerName>
        <issuerTradingSymbol>ROIV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001716729</rptOwnerCik>
            <rptOwnerName>SVF Investments (UK) Ltd</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>69 GROSVENOR STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LONDON</rptOwnerCity>
            <rptOwnerState>X0</rptOwnerState>
            <rptOwnerZipCode>W1K3JP</rptOwnerZipCode>
            <rptOwnerStateDescription>UNITED KINGDOM</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001699940</rptOwnerCik>
            <rptOwnerName>SoftBank Vision Fund L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>AZTEC GROUP HOUSE 11-15 SEATON PLACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ST. HELIER</rptOwnerCity>
            <rptOwnerState>Y9</rptOwnerState>
            <rptOwnerZipCode>JE40QH</rptOwnerZipCode>
            <rptOwnerStateDescription>JERSEY</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001716728</rptOwnerCik>
            <rptOwnerName>SVF GP (Jersey) Ltd</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>AZTEC GROUP HOUSE 11-15 SEATON PLACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ST. HELIER</rptOwnerCity>
            <rptOwnerState>Y9</rptOwnerState>
            <rptOwnerZipCode>JE40QH</rptOwnerZipCode>
            <rptOwnerStateDescription>JERSEY</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001716727</rptOwnerCik>
            <rptOwnerName>SVF Holdings (UK) LLP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>69 GROSVENOR STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LONDON</rptOwnerCity>
            <rptOwnerState>X0</rptOwnerState>
            <rptOwnerZipCode>W1K3JP</rptOwnerZipCode>
            <rptOwnerStateDescription>UNITED KINGDOM</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001731509</rptOwnerCik>
            <rptOwnerName>SB INVESTMENT ADVISERS (UK) LTD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>69 GROSVENOR STREET,</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LONDON</rptOwnerCity>
            <rptOwnerState>X0</rptOwnerState>
            <rptOwnerZipCode>W1K 3JP</rptOwnerZipCode>
            <rptOwnerStateDescription>UNITED KINGDOM</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>99375586</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Securities held of record by SVF Investments (UK) Limited. SVF GP (Jersey) Limited is the general partner of Softbank Vision Fund LP, which is the managing member of SVF Holdings (UK) LLP, which is the sole owner of SVF Investments (UK) Limited. SB Investment Advisers (UK) Limited (&quot;SBIA UK&quot;) has been appointed by SVF GP (Jersey) Limited as the alternative investment fund manager (&quot;AIFM&quot;) of SoftBank Vision Fund LP. SBIA UK is authorized and regulated by the UK Financial Conduct Authority and is exclusively responsible for making all decisions related to the acquisition, structuring, financing and disposal of SoftBank Vision Fund LP's investments.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>SVF Investments (UK) Limited, By: SB Investment Advisers (UK) Limited, its Manager, /s/ Brian Wheeler, as General Counsel</signatureName>
        <signatureDate>2021-10-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>SVF Holdings (UK) LLP, By: SB Investment Advisers (UK) Limited, its Manager, /s/ Brian Wheeler, as General Counsel</signatureName>
        <signatureDate>2021-10-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>SoftBank Vision Fund LP, By: SB Investment Advisers (UK) Limited, its Manager, /s/ Brian Wheeler, as General Counsel</signatureName>
        <signatureDate>2021-10-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>SVF GP (Jersey) Limited, By: /s/ Simon King, as Director</signatureName>
        <signatureDate>2021-10-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>SB Investment Advisers (UK) Limited, By: /s/ Brian Wheeler, as General Counsel</signatureName>
        <signatureDate>2021-10-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
