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

    <schemaVersion>X0407</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-06-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001720671</issuerCik>
        <issuerName>HashiCorp, Inc.</issuerName>
        <issuerTradingSymbol>HCP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001551568</rptOwnerCik>
            <rptOwnerName>MAYFIELD XIV, A CAYMAN ISLANDS EXEMPTED LIMITED PARTNERSHIP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001648253</rptOwnerCik>
            <rptOwnerName>Mayfield XIV Management (EGP), L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001648252</rptOwnerCik>
            <rptOwnerName>Mayfield XIV Management (UGP), Ltd.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001667217</rptOwnerCik>
            <rptOwnerName>MAYFIELD SELECT, A CAYMAN ISLANDS EXEMPTED LIMITED PARTNERSHIP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001708789</rptOwnerCik>
            <rptOwnerName>Mayfield Select Management (EGP), L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001708788</rptOwnerCik>
            <rptOwnerName>Mayfield Select Management (UGP), Ltd.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001807009</rptOwnerCik>
            <rptOwnerName>MF Leaders H-E, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001883973</rptOwnerCik>
            <rptOwnerName>MF Leaders Management, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2484 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-06-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2873395</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2873395</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11493581</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Mayfield XIV, a Cayman Islands Exempted Limited Partnership</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-06-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>312102</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>312102</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1248406</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Mayfield Select, a Cayman Islands Exempted Limited Partnership</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>345778</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>345778</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>MF Leaders H-E, L.P.</value>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each share of Class B Common Stock is convertible at any time into Class A Common Stock on a one-to-one basis at the reporting person's election and has no expiration date.</footnote>
        <footnote id="F2">Represents a pro-rata distribution in-kind by Mayfield XIV, a Cayman Islands Exempted Limited Partnership, or MF XIV, to its partners for no consideration.</footnote>
        <footnote id="F3">Represents a pro-rata distribution in-kind by Mayfield Select, a Cayman Islands Exempted Limited Partnership, or MF Select, to its partners for no consideration.</footnote>
        <footnote id="F4">Mayfield XIV Management (UGP), Ltd., a Cayman Islands Exempted Company (MF XIV UGP), is the general partner of Mayfield XIV Management (EGP), L.P., a Cayman Islands Exempted Limited Partnership (MF XIV EGP), which is the general partner of Mayfield XIV, a Cayman Islands Exempted Limited Partnership (MF XIV). Rajeev Batra, Navin Chaddha, and Urshit Parikh, the directors of MF XIV UGP, may be deemed to share beneficial ownership of the shares owned by MF XIV, but each of the individuals disclaims such beneficial ownership.</footnote>
        <footnote id="F5">Mayfield Select Management (UGP), Ltd., a Cayman Islands Exempted Company (MF Select UGP), is the general partner of Mayfield Select Management (EGP), L.P., a Cayman Islands Exempted Limited Partnership (MF Select EGP), which is the general partner of Mayfield Select, a Cayman Islands Exempted Limited Partnership (MF Select). Messrs. Batra, Chaddha, and Parikh, the directors of MF Select UGP, may be deemed to share beneficial ownership of the shares owned by MF Select, but each of the individuals disclaims such beneficial ownership.</footnote>
        <footnote id="F6">MF Leaders Management, L.L.C. (MF Leaders GP) is the general partner of MF Leaders H-E, L.P. (MF Leaders). Mr. Chaddha, the sole member of MF Leaders GP, may be deemed to share beneficial ownership of the shares owned by MF Leaders, but disclaims such beneficial ownership.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>MAYFIELD XIV, a Cayman Islands Exempted Limited Partnership By: MAYFIELD XIV MANAGEMENT (EGP), L.P., its General Partner By: MAYFIELD XIV MANAGEMENT (UGP), LTD., its General Partner By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MAYFIELD XIV MANAGEMENT (EGP), L.P. By: MAYFIELD XIV MANAGEMENT (UGP), LTD., its General Partner By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MAYFIELD XIV MANAGEMENT (UGP), LTD. By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MAYFIELD SELECT, a Cayman Islands Exempted Limited Partnership By: MAYFIELD SELECT MANAGEMENT (EGP), L.P., its General Partner By: MAYFIELD SELECT MANAGEMENT (UGP), LTD., its General Partner By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MAYFIELD SELECT MANAGEMENT (EGP), L.P. By: MAYFIELD SELECT MANAGEMENT (UGP), LTD., its General Partner By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MAYFIELD SELECT MANAGEMENT (UGP), LTD. By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MF LEADERS H-E, L.P., a Delaware limited partnership By: MF Leaders Management, L.L.C., its General Partner By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MF Leaders Management, L.L.C. By: /s/ Paul Kohli, Authorized Signatory</signatureName>
        <signatureDate>2023-06-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
