-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 ACCmYH15iU2VJpc/28ljCbPoEwuDWMb+HJeJ4t+VBs9moUzgchDgXyWwt10wh+T7
 D55wIca3hawAMlMog81O8Q==

<SEC-DOCUMENT>0001468730-10-000005.txt : 20100915
<SEC-HEADER>0001468730-10-000005.hdr.sgml : 20100915
<ACCEPTANCE-DATETIME>20100915121030
ACCESSION NUMBER:		0001468730-10-000005
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100913
FILED AS OF DATE:		20100915
DATE AS OF CHANGE:		20100915

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			bogachev nikolay v
		CENTRAL INDEX KEY:			0001468730

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05507
		FILM NUMBER:		101073347

	MAIL ADDRESS:	
		STREET 1:		9-3 SECHNEOVSKY PEREULOK
		CITY:			MOSCOW
		STATE:			1Z
		ZIP:			RUS-119034

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MAGELLAN PETROLEUM CORP /DE/
		CENTRAL INDEX KEY:			0000061398
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				060842255
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		10 COLUMBUS BLVD
		STREET 2:		10 FLOOR
		CITY:			HARTFORD
		STATE:			CT
		ZIP:			06106
		BUSINESS PHONE:		8602932006

	MAIL ADDRESS:	
		STREET 1:		10 COLUMBUS BLVD
		STREET 2:		10 FLOOR
		CITY:			HARTFORD
		STATE:			CT
		ZIP:			06106

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MAGELLAN PETROLEUM CORP PANAMA
		DATE OF NAME CHANGE:	19671130
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-09-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000061398</issuerCik>
        <issuerName>MAGELLAN PETROLEUM CORP /DE/</issuerName>
        <issuerTradingSymbol>MPET</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001468730</rptOwnerCik>
            <rptOwnerName>bogachev nikolay v</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>9-3 SECHNEOVSKY PEREULOK</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MOSCOW</rptOwnerCity>
            <rptOwnerState>1Z</rptOwnerState>
            <rptOwnerZipCode>RUS-119034</rptOwnerZipCode>
            <rptOwnerStateDescription>RUSSIAN FEDERATION</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-09-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>22732</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.88</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14398963</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by ECP Fund, SICAV-FIS</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15000</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On September 13, 2010, ECP Fund, SICAV-FIS (the &quot;ECP Fund&quot;) (formerly known as YEP I, SICAV-FIS) sold an aggregate of 37,574 shares of the issuer's common stock pursuant to Rule 144.  On the date of sale, the reporting person indirectly held a 60.5% equity interest in the ECP Fund.  Accordingly, the reporting person's pecuniary interest in the issuer's shares held by the ECP Fund decreased proportionately by 22,732 shares.</footnote>
        <footnote id="F2">Following this sale by the ECP Fund, the reporting person beneficially owns 15,000 shares of the issuer's common stock directly and an aggregate of 14,398,963 shares of the issuer's common stock indirectly, of which 13,612,463 shares are held by Young Energy Prize S.A. and 786,500 shares are held by the ECP Fund.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Nikolay V. Bogachev</signatureName>
        <signatureDate>2010-09-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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