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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-05-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001490892</issuerCik>
        <issuerName>CoreSite Realty Corp</issuerName>
        <issuerTradingSymbol>COR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001548624</rptOwnerCik>
            <rptOwnerName>Carlyle Group Management L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001527166</rptOwnerCik>
            <rptOwnerName>Carlyle Group Inc.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001548626</rptOwnerCik>
            <rptOwnerName>Carlyle Holdings I GP Inc.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001548627</rptOwnerCik>
            <rptOwnerName>Carlyle Holdings I GP Sub L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001548628</rptOwnerCik>
            <rptOwnerName>Carlyle Holdings I L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001790577</rptOwnerCik>
            <rptOwnerName>CG Subsidiary Holdings L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000933790</rptOwnerCik>
            <rptOwnerName>TC Group, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W., SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001548639</rptOwnerCik>
            <rptOwnerName>TC Group Sub L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CARLYLE GROUP, 1001</rptOwnerStreet1>
            <rptOwnerStreet2>PENNSYLVANIA AVE., N.W. SUITE 220 SOUTH</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20004-2505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-05-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2620000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2620000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-05-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2620000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>118.4607</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Operating Partnership Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-05-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2620000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2620000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8105390</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The operating partnership units are redeemable at any time for cash or, at the election of the Issuer, exchangeable for shares of common stock on a one-for-one basis, and have no expiration date.</footnote>
        <footnote id="F2">Following the transactions reported herein, consists of (i) 957,374 common units held by CoreSite CRP III Holdings, LLC; (ii) 193,940 common units held by CoreSite CRP III Holdings (VCOC), LLC; (iii) 670,930 common units held by CoreSite CRP IV Holdings, LLC; (iv) 114,259 common units held by CoreSite CRP IV Holdings (VCOC I), LLC; (v) 293,669 common units held by CoreSite CRP IV Holdings (VCOC II), LLC; and (vi) 5,875,218 common units held by CoreSite CRP V Holdings, LLC.</footnote>
        <footnote id="F3">Following an internal reorganization and by reason of the relationships described below, the reporting person may be deemed to share beneficial ownership of the securities reported herein. The reporting person disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F4">Carlyle Group Management L.L.C. holds an irrevocable proxy to vote a majority of the shares of The Carlyle Group Inc., which is a publicly traded entity listed on NASDAQ. The Carlyle Group Inc. is the sole shareholder of Carlyle Holdings I GP Inc., which is the managing member of Carlyle Holdings I GP Sub L.L.C., which is the general partner of Carlyle Holdings I L.P., which, with respect to the securities reported herein, is the managing member of CG Subsidiary Holdings L.L.C., which is the sole member of TC Group, L.L.C., which is the general partner of TC Group Sub L.P., which is the sole member of each of Carlyle Realty III GP, L.L.C., CRP III AIV GP, L.L.C., Carlyle Realty IV GP, L.L.C., CRP IV AIV GP, L.L.C. and Carlyle Realty V GP, L.L.C.</footnote>
        <footnote id="F5">Carlyle Realty III GP, L.L.C. is the general partner of Carlyle Realty III, L.P. which is the manager of CoreSite CRP III Holdings, LLC. CRP III AIV GP, L.L.C. is the general partner of CRP III AIV GP, L.P., which is the general partner of CRQP III AIV, L.P., which is the sole member of CoreSite CRP III Holdings (VCOC), LLC. Carlyle Realty IV GP, L.L.C. is the general partner of Carlyle Realty IV, L.P., which is the manager of CoreSite CRP IV Holdings, LLC. CRP IV AIV GP, L.L.C. is the general partner of CRP IV AIV GP, L.P., which is the general partner of each of CRP IV-A AIV, L.P. and CRQP IV AIV, L.P., which are the managing members of CoreSite CRP IV Holdings (VCOC I), LLC and CoreSite CRP IV Holdings (VCOC II), LLC, respectively. Carlyle Realty V GP, L.L.C. is the general partner of Carlyle Realty V, L.P., which is the manager of CoreSite CRP V Holdings, LLC.</footnote>
    </footnotes>

    <remarks>Due to the limitations of the electronic filing system Carlyle Realty III GP, L.L.C., Carlyle Realty III, L.P., CoreSite CRP III Holdings, LLC, CRP III AIV GP, L.L.C., CRP III AIV GP, L.P., CRQP III AIV, L.P., CoreSite CRP III Holdings (VCOC), LLC, Carlyle Realty IV GP, L.L.C., Carlyle Realty IV, L.P., CoreSite CRP IV Holdings, LLC, CRP IV AIV GP, L.L.C., CRP IV AIV GP, L.P., CRP IV-A AIV, L.P., CRQP IV AIV, L.P., CoreSite CRP IV Holdings (VCOC I), LLC, CoreSite CRP IV Holdings (VCOC II), LLC, Carlyle Realty V GP, L.L.C., Carlyle Realty V, L.P. and CoreSite CRP V Holdings, LLC are filing a separate Form 4.</remarks>

    <ownerSignature>
        <signatureName>Carlyle Group Management L.L.C., By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>The Carlyle Group Inc., By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Carlyle Holdings I GP Inc., By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Carlyle Holdings I GP Sub L.L.C., By: Carlyle Holdings I GP Inc., its managing member, By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Carlyle Holdings I L.P., By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CG Subsidiary Holdings L.L.C., By: Carlyle Holdings I L.P., its managing member, By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>TC Group, L.L.C., By: CG Subsidiary Holdings L.L.C., its managing member, By: Carlyle Holdings I L.P., its managing member, By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>TC Group Sub L.P., By: TC Group, L.L.C., its general partner, By: CG Subsidiary Holdings L.L.C., its managing member, By: Carlyle Holdings I L.P., its managing member, By: /s/ Anne Frederick, Attorney-in-fact for Curtis L. Buser, Chief Financial Officer</signatureName>
        <signatureDate>2020-05-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
