<SEC-DOCUMENT>0001562180-21-003880.txt : 20210601
<SEC-HEADER>0001562180-21-003880.hdr.sgml : 20210601
<ACCEPTANCE-DATETIME>20210601173350
ACCESSION NUMBER:		0001562180-21-003880
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210527
FILED AS OF DATE:		20210601
DATE AS OF CHANGE:		20210601

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Freund John Gordon
		CENTRAL INDEX KEY:			0001296771

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38701
		FILM NUMBER:		21986684

	MAIL ADDRESS:	
		STREET 1:		125 UNIVERSITY AVE.
		STREET 2:		C/O SKYLINE VENTURES
		CITY:			PALO ALTO
		STATE:			CA
		ZIP:			94301

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SI-BONE, Inc.
		CENTRAL INDEX KEY:			0001459839
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				262216351
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		471 EL CAMINO REAL, SUITE 101
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95050
		BUSINESS PHONE:		4082070700

	MAIL ADDRESS:	
		STREET 1:		471 EL CAMINO REAL, SUITE 101
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95050

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SI-Bone Inc.
		DATE OF NAME CHANGE:	20090326
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primarydocument.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-05-27</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0001459839</issuerCik>
        <issuerName>SI-BONE, Inc.</issuerName>
        <issuerTradingSymbol>SIBN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001296771</rptOwnerCik>
            <rptOwnerName>Freund John Gordon</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SKYLINE VENTURES</rptOwnerStreet1>
            <rptOwnerStreet2>525 UNIVERSITY AVENUE, SUITE 1350</rptOwnerStreet2>
            <rptOwnerCity>PALO ALTO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-05-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>26367.00</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30.9297</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>428678.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Skyline Venture Partners V, LP</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-05-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>45220.00</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30.0629</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>383458.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Skyline Venture Partners V, LP</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100750.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By John Freund Family Partnership IV, L.P</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $30.43 to $31.76, inclusive. The Reporting Person undertakes to provide the Issuer, any securityholder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in these footnotes.</footnote>
        <footnote id="F2">Shares held by SVP V. Skyline Venture Management V, LLC (&quot;LLC&quot;) is the general partner of SVP V and as such may be deemed to have
voting and investment power with respect to the securities of SVP V. Reporting Person, a member of Issuer's board of directors, is a managing director of LLC and may be deemed to have voting and investment power with respect to the securities held by SVP V. Reporting Person disclaims beneficial ownership of such securities, except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F3">The price reported in column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $29.67  to $30.99, inclusive. The Reporting Person undertakes to provide the Issuer, any securityholder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in these footnotes.</footnote>
        <footnote id="F4">Shares held by John Freund Family Partnership IV, L.P. (&quot;Family LP&quot;). Reporting Person, a member of Issuer's board of directors, is a general
partner of Family LP and may be deemed to have voting and investment power with respect to the securities held by Family LP. Reporting
Person disclaims beneficial ownership of such securities, except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Michael A. Pisetsky, Attorney-in-Fact for John G. Freund</signatureName>
        <signatureDate>2021-06-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
