-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 62N9y3rbeGeKLAPVjjw3JQ==

<SEC-DOCUMENT>0001432405-10-000020.txt : 20100928
<SEC-HEADER>0001432405-10-000020.hdr.sgml : 20100928
<ACCEPTANCE-DATETIME>20100928144426
ACCESSION NUMBER:		0001432405-10-000020
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100928
FILED AS OF DATE:		20100928
DATE AS OF CHANGE:		20100928

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Lemon Scott B
		CENTRAL INDEX KEY:			0001433583

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-53198
		FILM NUMBER:		101093381

	MAIL ADDRESS:	
		STREET 1:		3118 PASCAGOULA STREET
		CITY:			PASCAGOULA
		STATE:			MS
		ZIP:			39567

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Merchants & Marine Bancorp, Inc.
		CENTRAL INDEX KEY:			0001432405
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			MS
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3118 PASCAGOULA STREET
		CITY:			PASCAGOULA
		STATE:			MS
		ZIP:			39567
		BUSINESS PHONE:		228-762-3311

	MAIL ADDRESS:	
		STREET 1:		3118 PASCAGOULA STREET
		CITY:			PASCAGOULA
		STATE:			MS
		ZIP:			39567
</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>2010-09-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001432405</issuerCik>
        <issuerName>Merchants &amp; Marine Bancorp, Inc.</issuerName>
        <issuerTradingSymbol>none</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001433583</rptOwnerCik>
            <rptOwnerName>Lemon Scott B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3118 PASCAGOULA STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PASCAGOULA</rptOwnerCity>
            <rptOwnerState>MS</rptOwnerState>
            <rptOwnerZipCode>39567</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock Par Value $2.50</value>
            </securityTitle>
            <transactionDate>
                <value>2010-09-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>150</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>40</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>395</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/ Scott B Lemon</signatureName>
        <signatureDate>2010-09-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----