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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019ea94d-afa9-7731-b4c3-d741cebac09f,g:7d774e4e-8c54-44e9-a524-3fb8c549f6cf-->
<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-20260603.xsd#CoverPage"/>
  <link:presentationLink xlink:role="http://fastly.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CoverAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019ea94d-afa9-7ed9-a8d0-ada8d0a36a86" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_DocumentType_019ea94d-afa9-7ed9-a8d0-ada8d0a36a86" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019ea94d-afa9-72e0-8f11-544d3f6893e5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_DocumentPeriodEndDate_019ea94d-afa9-72e0-8f11-544d3f6893e5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019ea94d-afa9-757b-a6bb-5916f15d9899" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityRegistrantName_019ea94d-afa9-757b-a6bb-5916f15d9899" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019ea94d-afa9-70e4-b57e-ad3dba830d88" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityCentralIndexKey_019ea94d-afa9-70e4-b57e-ad3dba830d88" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019ea94d-afa9-7d3c-b0c9-29eee8ca9863" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_AmendmentFlag_019ea94d-afa9-7d3c-b0c9-29eee8ca9863" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019ea94d-afa9-7670-98a6-b6ae39fc688b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019ea94d-afa9-7670-98a6-b6ae39fc688b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019ea94d-afa9-78b1-89ba-da5f5899bd17" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityFileNumber_019ea94d-afa9-78b1-89ba-da5f5899bd17" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019ea94d-afa9-7715-b9f5-1f3e3288e7c4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityTaxIdentificationNumber_019ea94d-afa9-7715-b9f5-1f3e3288e7c4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019ea94d-afa9-7f70-8739-2f8a8b0b6783" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityAddressAddressLine1_019ea94d-afa9-7f70-8739-2f8a8b0b6783" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019ea94d-afa9-7bea-a154-e785437f97d8" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityAddressCityOrTown_019ea94d-afa9-7bea-a154-e785437f97d8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019ea94d-afa9-7009-84da-53ab2bb56cfc" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityAddressStateOrProvince_019ea94d-afa9-7009-84da-53ab2bb56cfc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019ea94d-afa9-7db3-a9b1-fa96972f0877" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityAddressPostalZipCode_019ea94d-afa9-7db3-a9b1-fa96972f0877" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019ea94d-afa9-7934-ba1a-ab70fbbdfb54" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_CityAreaCode_019ea94d-afa9-7934-ba1a-ab70fbbdfb54" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019ea94d-afa9-7eca-883a-3a5725fd7250" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_LocalPhoneNumber_019ea94d-afa9-7eca-883a-3a5725fd7250" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019ea94d-afa9-759a-89cb-f6f12ff06201" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_WrittenCommunications_019ea94d-afa9-759a-89cb-f6f12ff06201" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019ea94d-afa9-7e29-a11c-c44c45dd7135" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_SolicitingMaterial_019ea94d-afa9-7e29-a11c-c44c45dd7135" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019ea94d-afa9-769b-b8c1-c63931592b0c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:presentationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_PreCommencementTenderOffer_019ea94d-afa9-769b-b8c1-c63931592b0c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019ea94d-afa9-7fb6-9880-c81df00534d3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:presentationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019ea94d-afa9-7fb6-9880-c81df00534d3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019ea94d-afa9-74b3-8689-e0dba53f3ead" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:presentationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_Security12bTitle_019ea94d-afa9-74b3-8689-e0dba53f3ead" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019ea94d-afa9-7b03-acf8-74bffeee4a41" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:presentationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_TradingSymbol_019ea94d-afa9-7b03-acf8-74bffeee4a41" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019ea94d-afa9-7efb-8c4a-2aa902fe97c0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:presentationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_SecurityExchangeName_019ea94d-afa9-7efb-8c4a-2aa902fe97c0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019ea94d-afa9-799b-95c4-ab0a564c2c28" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:presentationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_019ea94d-afa9-732c-a81d-7e1dcc5a38b5" xlink:to="loc_dei_EntityEmergingGrowthCompany_019ea94d-afa9-799b-95c4-ab0a564c2c28" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
</link:linkbase>
