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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-06-09</periodOfReport>

    <issuer>
        <issuerCik>0001517342</issuerCik>
        <issuerName>PACIFIC DRILLING S.A.</issuerName>
        <issuerTradingSymbol>PACD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001317338</rptOwnerCik>
            <rptOwnerName>Avenue Capital Management II, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL GROUP</rptOwnerStreet1>
            <rptOwnerStreet2>11 WEST 42ND STREET, 9TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isTenPercentOwner>true</isTenPercentOwner>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001389850</rptOwnerCik>
            <rptOwnerName>Avenue Capital Management II GenPar, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL GROUP,</rptOwnerStreet1>
            <rptOwnerStreet2>11 WEST 42ND STREET, 9TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isTenPercentOwner>true</isTenPercentOwner>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001673020</rptOwnerCik>
            <rptOwnerName>Avenue Energy Opportunities Fund II, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL GROUP,</rptOwnerStreet1>
            <rptOwnerStreet2>11 WEST 42ND STREET, 9TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isTenPercentOwner>true</isTenPercentOwner>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001641985</rptOwnerCik>
            <rptOwnerName>AVENUE PPF OPPORTUNITIES FUND, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL GROUP,</rptOwnerStreet1>
            <rptOwnerStreet2>11 WEST 42ND STREET, 9TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isTenPercentOwner>true</isTenPercentOwner>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001613152</rptOwnerCik>
            <rptOwnerName>Avenue Energy Opportunities Fund, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL GROUP,</rptOwnerStreet1>
            <rptOwnerStreet2>11 WEST 42ND STREET, 9TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isTenPercentOwner>true</isTenPercentOwner>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001622832</rptOwnerCik>
            <rptOwnerName>Avenue Special Opportunities Fund II, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL GROUP,</rptOwnerStreet1>
            <rptOwnerStreet2>11 WEST 42ND STREET, 9TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isTenPercentOwner>true</isTenPercentOwner>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001688173</rptOwnerCik>
            <rptOwnerName>Avenue Strategic Opportunities Fund, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL GROUP,</rptOwnerStreet1>
            <rptOwnerStreet2>11 WEST 42ND STREET, 9TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isTenPercentOwner>true</isTenPercentOwner>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2020-06-09</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2020-06-09</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3229912</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.814</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10360530</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Collectively, the securities (the &quot;Common Shares&quot;) reported in this Form 4 are held directly by: (i) Avenue Energy Opportunities Fund, L.P., Avenue Energy Opportunities Fund II, L.P., Avenue PPF Opportunities Fund, L.P., Avenue Special Opportunities Fund II, L.P. and Avenue Strategic Opportunities Fund, L.P. (the &quot;US Funds&quot;) and (ii) Avenue ASRS Europe Opportunities Fund, L.P., Avenue Europe Opportunities Master Fund, L.P., Avenue Europe Special Situations Fund III (Euro), L.P., and Avenue Europe Special Situations Fund III (U.S.), L.P. (the &quot;Euro Funds&quot; and together with the US Funds, the &quot;Funds&quot;).</footnote>
        <footnote id="F2">Avenue Capital Management II, L.P. is the investment manager of the US Funds and may be deemed to have voting and dispositive power over the 7,344,962 Common Shares owned by such entities. Avenue Europe International Management, L.P. is the investment manager of the Euro Funds and may be deemed to have voting and dispositive power over the 3,015,568 Common Shares owned by such entities.</footnote>
        <footnote id="F3">Marc Lasry is the managing member of Avenue Capital Management II GenPar, LLC and Avenue Europe International Management GenPar, LLC. Mr. Lasry may be deemed to be the indirect beneficial owner of the securities reported by the Funds by reason of his ability to direct the vote and/or disposition of such securities, and his pecuniary interest in such shares (within the meaning of Rule 16a-1(a)(2) under the Exchange Act) is a fractional interest in such amount.</footnote>
    </footnotes>

    <remarks>This Form 4 is being filed in two parts. This is Part 1 of 2.</remarks>

    <ownerSignature>
        <signatureName>AVENUE CAPITAL MANAGEMENT II, L.P.
By: Avenue Capital Management II GenPar, LLC, its General Partner By: /s/ Andrew K. Schinder, Attorney-in-Fact for Marc Lasry, Managing Member</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>AVENUE CAPITAL MANAGEMENT II GENPAR, LLC
By: /s/ Andrew K. Schinder, Attorney-in-Fact for Marc Lasry, Managing Member</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Avenue Energy Opportunities Fund II, L.P.
By: Avenue Energy Opportunities Partners II, LLC, its General Partner By: GL Energy Opportunities Partners II, LLC, its Sole Member By: /s/ Andrew K. Schinder, Attorney-in-Fact for Marc Lasry, Managing Member</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>AVENUE PPF OPPORTUNITIES FUND, L.P.
By: Avenue PPF Opportunities Fund GenPar, LLC, its General Partner By: /s/ Andrew K. Schinder, Attorney-in-Fact for Marc Lasry, Managing Member</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>AVENUE ENERGY OPPORTUNITIES FUND, L.P.
By: Avenue Energy Opportunities Partners, LLC, its General Partner By: GL Energy Opportunities Partners, LLC, its Managing Member By: /s/ Andrew K. Schinder, Attorney-in-Fact for Marc Lasry, Managing Member</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>AVENUE SPECIAL OPPORTUNTIES FUND II, L.P.
By: Avenue SO Capital Partners II, LLC, its General Partner
By: GL SO Partners II, LLC, its Sole Member
By: /s/ Andrew K. Schinder, Attorney-in-Fact for Marc Lasry, Managing Member</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>AVENUE STRATEGIC OPPORTUNITIES FUND, L.P.
By: Avenue Strategic Opportunities Fund GenPar, LLC, its General Partner By: GL Strategic Opportunities Partners, LLC, its Sole Member By: /s/ Andrew K. Schinder, Attorney-in-Fact for Marc Lasry, Managing Member</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
