<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-06-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001620463</issuerCik>
        <issuerName>Athira Pharma, Inc.</issuerName>
        <issuerTradingSymbol>ATHA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001604834</rptOwnerCik>
            <rptOwnerName>Litton Mark James</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ATHIRA PHARMA, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>18706 NORTH CREEK PARKWAY, SUITE 104</rptOwnerStreet2>
            <rptOwnerCity>BOTHELL</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98011</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2022-05-18</value>
                <footnoteId id="F2"/>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>757</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.06</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>116515</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-06-22</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>136515</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-06-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F5"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7960</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2.69</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>128555</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6563</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Irrevocable Trust of OSL</value>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6563</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Irrevocable Trust of SWL</value>
                    <footnoteId id="F8"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6563</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Irrevocable Trust of WGL</value>
                    <footnoteId id="F9"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person is voluntarily reporting the acquisition of shares of the issuer's common stock pursuant to the Athira Pharma, Inc. 2020 Employee Stock Purchase Plan (&quot;ESPP&quot;), for the ESPP Purchase Period (as defined in the ESPP) of November 18, 2021 through May 18, 2022. This transaction is also exempt under Rule 16b-3(c).</footnote>
        <footnote id="F2">The Purchase Period ended May 18, 2022 and is the Purchase Period comprising the Offering Period (as defined in the ESPP) that began November 18, 2021.</footnote>
        <footnote id="F3">In accordance with the ESPP, these shares were purchased based on 85% of the closing price on May 18, 2022.</footnote>
        <footnote id="F4">On November 3, 2021, the reporting person was granted restricted stock units (&quot;RSUs&quot;) representing 60,000 shares of Common Stock of the Issuer. The RSUs were scheduled to vest according to the following schedule: (1) one third (1/3rd) of the number of shares subject to the RSU award vest at the completion of the public readout of topline results of the Issuer's ACT-AD Phase 2 clinical trial; (2) one third (1/3rd) of the number of shares subject to the RSU award vest at the completion of the public readout of topline results of the Issuer's LIFT-AD Phase 2/3 clinical trial (the &quot;LIFT-AD Readout&quot;) and (3) one third (1/3rd) of the number of shares subject to the RSU award vest six (6) months after the LIFT-AD Readout, in each case subject to continued service with the Issuer through the applicable vesting date. On June 22, 2022, the Issuer completed the public readout of topline results of the ACT-AD Phase 2 clinical trial and 20,000 RSUs vested and settled on such date.</footnote>
        <footnote id="F5">The reported shares were sold to cover the Issuer's tax withholding obligations in connection with the vesting of RSUs. Such sale was made pursuant to an Issuer-mandated policy and was not subject to discretion.</footnote>
        <footnote id="F6">The &quot;Amount&quot; and &quot;Price&quot; reported in this Column 4 reflect the aggregate number and weighted-average price, respectively, of shares sold. These shares were sold in multiple transactions at prices ranging from $2.62 to $2.78, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range set forth herein.</footnote>
        <footnote id="F7">Reflects Common Stock held by Irrevocable Trust of OSL held for the benefit of Dr. Litton's children.</footnote>
        <footnote id="F8">Reflects Common Stock held by Irrevocable Trust of SWL held for the benefit of Dr. Litton's children.</footnote>
        <footnote id="F9">Reflects Common Stock held by Irrevocable Trust of WGL held for the benefit of Dr. Litton's children.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Glenna Mileson, Attorney-in-Fact on behalf of Mark Litton</signatureName>
        <signatureDate>2022-06-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
