<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:7657df80-7ba5-4aa7-a6b6-2fe043f0b7bc,g:3b94f727-9bdc-4db2-a599-6fbf966f03cf-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://fastly.com/role/CoverPage" xlink:type="simple" xlink:href="fsly-20211103.xsd#CoverPage"/>
  <link:presentationLink xlink:role="http://fastly.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_CoverAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_2faf43f5-3206-44ad-b417-4682da634e3c" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentType"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_DocumentType_2faf43f5-3206-44ad-b417-4682da634e3c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_21fdd9dc-e1ff-4719-bffa-ce1c5f9bf059" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentPeriodEndDate"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_DocumentPeriodEndDate_21fdd9dc-e1ff-4719-bffa-ce1c5f9bf059" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_db13313d-b611-4497-895f-7d1b10376ff7" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityRegistrantName"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityRegistrantName_db13313d-b611-4497-895f-7d1b10376ff7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_1b28351a-b0d7-4894-9d69-20bc5016f291" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityCentralIndexKey"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityCentralIndexKey_1b28351a-b0d7-4894-9d69-20bc5016f291" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_ace29afe-5331-419b-aebe-707adb05fee4" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_AmendmentFlag"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_AmendmentFlag_ace29afe-5331-419b-aebe-707adb05fee4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_a434b627-88ef-4df6-b6c8-4eec56adaaff" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityIncorporationStateCountryCode_a434b627-88ef-4df6-b6c8-4eec56adaaff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_7276937d-f7ed-4551-882e-4b3a42b3099a" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityFileNumber"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityFileNumber_7276937d-f7ed-4551-882e-4b3a42b3099a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_fffb18c7-216c-4a3d-b32f-b71076844679" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityTaxIdentificationNumber_fffb18c7-216c-4a3d-b32f-b71076844679" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_7776c4c1-005a-480f-b80c-404813acdb92" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressAddressLine1"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityAddressAddressLine1_7776c4c1-005a-480f-b80c-404813acdb92" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_48ade963-34a6-4df5-94ea-05b914ef53a4" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressCityOrTown"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityAddressCityOrTown_48ade963-34a6-4df5-94ea-05b914ef53a4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_9b9bc73a-2cd4-4bee-8d01-229d6c5b8efe" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressStateOrProvince"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityAddressStateOrProvince_9b9bc73a-2cd4-4bee-8d01-229d6c5b8efe" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_a5a8fa5b-c859-4480-b4af-9b4bdad34c75" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressPostalZipCode"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityAddressPostalZipCode_a5a8fa5b-c859-4480-b4af-9b4bdad34c75" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_7dc0698f-7486-47e8-b1bd-45c76b637424" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_CityAreaCode"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_CityAreaCode_7dc0698f-7486-47e8-b1bd-45c76b637424" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_4f0ea6bf-8b30-465f-a3b6-86efc420a6e1" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LocalPhoneNumber"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_LocalPhoneNumber_4f0ea6bf-8b30-465f-a3b6-86efc420a6e1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_fdf30e55-0702-4b5b-9382-8e9d45475c28" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_WrittenCommunications"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_WrittenCommunications_fdf30e55-0702-4b5b-9382-8e9d45475c28" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_5ee09201-0675-47da-866d-e2b9eee10852" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_SolicitingMaterial"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_SolicitingMaterial_5ee09201-0675-47da-866d-e2b9eee10852" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_376d9fb5-66c9-4742-9cd2-24ec8bb94787" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_PreCommencementTenderOffer"/>
    <link:presentationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_PreCommencementTenderOffer_376d9fb5-66c9-4742-9cd2-24ec8bb94787" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_119b2ab8-a0ab-47a6-81f4-ee6822082d82" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:presentationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_119b2ab8-a0ab-47a6-81f4-ee6822082d82" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_e976a75e-ab75-4209-a54a-3b75190220f1" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_Security12bTitle"/>
    <link:presentationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_Security12bTitle_e976a75e-ab75-4209-a54a-3b75190220f1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_838d999e-0724-4d6e-983d-3778d6573e27" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_TradingSymbol"/>
    <link:presentationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_TradingSymbol_838d999e-0724-4d6e-983d-3778d6573e27" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_094b73ac-1f0b-491d-996d-53e22986fb75" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_SecurityExchangeName"/>
    <link:presentationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_SecurityExchangeName_094b73ac-1f0b-491d-996d-53e22986fb75" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_c8effc8d-51e5-44d9-ba63-1534a9c4e33b" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:presentationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_10f84f6b-0c0b-4524-9b19-7eb02cb70855" xlink:to="loc_dei_EntityEmergingGrowthCompany_c8effc8d-51e5-44d9-ba63-1534a9c4e33b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
</link:linkbase>


