-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 LLIyza2Emc4jpbAk1Hsi2g0W1tAD8PNBP4okXAOfCkr8HEP+Ve+qmj9B88X5G8nS
 dTSpuCXAQwJ+DDN3RMa/0w==

<SEC-DOCUMENT>0001347815-10-000025.txt : 20100611
<SEC-HEADER>0001347815-10-000025.hdr.sgml : 20100611
<ACCEPTANCE-DATETIME>20100611085305
ACCESSION NUMBER:		0001347815-10-000025
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100610
FILED AS OF DATE:		20100611
DATE AS OF CHANGE:		20100611

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FAWCETT WILLIAM F
		CENTRAL INDEX KEY:			0001244611

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33364
		FILM NUMBER:		10891611

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Flagstone Reinsurance Holdings, S.A.
		CENTRAL INDEX KEY:			0001347815
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				980481623
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		37 VAL ST. ANDR?
		CITY:			GRAND DUCHY OF LUXEMBOURG
		STATE:			N4
		ZIP:			L-1128
		BUSINESS PHONE:		352 273 515 30

	MAIL ADDRESS:	
		STREET 1:		37 VAL ST. ANDR?
		CITY:			GRAND DUCHY OF LUXEMBOURG
		STATE:			N4
		ZIP:			L-1128

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Flagstone Reinsurance Holdings Ltd
		DATE OF NAME CHANGE:	20051222
</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>2010-06-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001347815</issuerCik>
        <issuerName>Flagstone Reinsurance Holdings, S.A.</issuerName>
        <issuerTradingSymbol>FSR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001244611</rptOwnerCik>
            <rptOwnerName>FAWCETT WILLIAM F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FLAGSTONE REINSURANCE HOLDINGS, S.A.</rptOwnerStreet1>
            <rptOwnerStreet2>37, VAL ST. ANDRE</rptOwnerStreet2>
            <rptOwnerCity>LUXEMBOURG</rptOwnerCity>
            <rptOwnerState>N4</rptOwnerState>
            <rptOwnerZipCode>L-1128</rptOwnerZipCode>
            <rptOwnerStateDescription>LUXEMBOURG</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>General Counsel</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2010-06-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.486</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3100</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/ William F. Fawcett</signatureName>
        <signatureDate>2010-06-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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