<SEC-DOCUMENT>0001672825-26-000001.txt : 20260317
<SEC-HEADER>0001672825-26-000001.hdr.sgml : 20260317
<ACCEPTANCE-DATETIME>20260317162514
ACCESSION NUMBER:		0001672825-26-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260316
FILED AS OF DATE:		20260317
DATE AS OF CHANGE:		20260317

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Mueller David J
		CENTRAL INDEX KEY:			0001672825
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42584
		FILM NUMBER:		26762321

	MAIL ADDRESS:	
		STREET 1:		10 TERRACE ROAD
		CITY:			LADERA RANCH
		STATE:			CA
		ZIP:			92694

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SmartStop Self Storage REIT, Inc.
		CENTRAL INDEX KEY:			0001585389
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		ORGANIZATION NAME:           	05 Real Estate & Construction
		EIN:				461722812
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		10 TERRACE ROAD
		CITY:			LADERA RANCH
		STATE:			CA
		ZIP:			92694
		BUSINESS PHONE:		949 429 6600

	MAIL ADDRESS:	
		STREET 1:		10 TERRACE ROAD
		CITY:			LADERA RANCH
		STATE:			CA
		ZIP:			92694

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Strategic Storage Trust II, Inc.
		DATE OF NAME CHANGE:	20130828
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001585389</issuerCik>
        <issuerName>SmartStop Self Storage REIT, Inc.</issuerName>
        <issuerTradingSymbol>SMA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001672825</rptOwnerCik>
            <rptOwnerName>Mueller David J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10 TERRACE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LADERA RANCH</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92694</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>1</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>425</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.81</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6765.87</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Long-Term Incentive Plan Units</value>
                <footnoteId id="F2"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7234.25</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7234.25</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Long-Term Incentive Plan Units</value>
                <footnoteId id="F2"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9598</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9598</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 15, 2025.</footnote>
        <footnote id="F2">Represents long-term incentive plan units (&quot;LTIP Units&quot;) of SmartStop OP, L.P., the Issuer's operating partnership (the &quot;Operating Partnership&quot;). Vested LTIP Units are convertible into common units of the Operating Partnership (&quot;Common Units&quot;). Common Units are redeemable by the holder for, at the election of the Issuer, shares of the Issuer's Common Stock on a one-for-one basis or the cash value of such shares.</footnote>
        <footnote id="F3">Represents 7,234.25 LTIP Units previously reported as being owned by the Reporting Person. The LTIP Units were issued to the Reporting Person in connection with his reelection to the board of directors and vest one year from each such reelection.</footnote>
        <footnote id="F4">Represents 9,598 LTIP Units previously reported as being owned by the Reporting Person, which LTIP Units vest ratably over four years commencing on the first anniversary of the issuance thereof, subject to the Reporting Person's continued employment or service through each vesting date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ David J. Mueller</signatureName>
        <signatureDate>2026-03-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
