-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 TiUP/MomPegKk5tapctv2gRnkNnlYnGVfKgTNH68WcRRIE52CDGWjSrvf9x+PIHu
 58SCXDRSdlUuF1clUbFpQQ==

<SEC-DOCUMENT>0000897485-08-000018.txt : 20080801
<SEC-HEADER>0000897485-08-000018.hdr.sgml : 20080801
<ACCEPTANCE-DATETIME>20080801095650
ACCESSION NUMBER:		0000897485-08-000018
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080731
FILED AS OF DATE:		20080801
DATE AS OF CHANGE:		20080801

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MERCER INTERNATIONAL INC
		CENTRAL INDEX KEY:			0000075659
		STANDARD INDUSTRIAL CLASSIFICATION:	PULP MILLS [2611]
		IRS NUMBER:				916087550
		STATE OF INCORPORATION:			WA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		14900 INTERURBAN AVENUE SOUTH
		STREET 2:		SUITE 282
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98168
		BUSINESS PHONE:		2066744639

	MAIL ADDRESS:	
		STREET 1:		14900 INTERURBAN AVENUE SOUTH
		STREET 2:		SUITE 282
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98168

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ASIAMERICA EQUITIES LTD
		DATE OF NAME CHANGE:	19920109

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PACIFIC WEST REALTY TRUST
		DATE OF NAME CHANGE:	19860219

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KELLOGG PETER R
		CENTRAL INDEX KEY:			0000897485

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-09409
		FILM NUMBER:		08983606

	BUSINESS ADDRESS:	
		STREET 1:		C/O SPEAR LEEDS & KELLOGG
		STREET 2:		120 BROADWAY
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10271
		BUSINESS PHONE:		2123895840

	MAIL ADDRESS:	
		STREET 1:		48 WALL STREET
		STREET 2:		C/O IAT REINSURANCE CO LTD
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10005
</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>2008-07-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000075659</issuerCik>
        <issuerName>MERCER INTERNATIONAL INC</issuerName>
        <issuerTradingSymbol>MERC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000897485</rptOwnerCik>
            <rptOwnerName>KELLOGG PETER R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>48 WALL STREET</rptOwnerStreet1>
            <rptOwnerStreet2>C/O IAT REINSURANCE CO LTD</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10005</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.077</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5430909</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>BY IAT REINSURANCE CO LTD</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>0</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>160162</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>8.8% CONVERTIBLE SENIOR NOTES</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>7.75</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-07-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>0</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2007-10-10</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-10-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON SHARES</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1645161</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>BY IAT REINSURANCE CO LTD</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">IAT REINSURANCE CO LTD.,A BERMUDA CORPORATION OF WHICH MR KELLOGG IS THE SOLE HOLDER OF VOTING STOCK.MR KELLOGG DISCLAIMS BENEFICIAL OWNERSHIP OF THESE SHARES.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>PETER R KELLOGG/S/MARGAURITE GORMAN- ATTORNEY IN FACT</signatureName>
        <signatureDate>2008-08-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----