diff --git a/src/core/drive/navigator.ts b/src/core/drive/navigator.ts
index 991b11a5e..39d2fd738 100644
--- a/src/core/drive/navigator.ts
+++ b/src/core/drive/navigator.ts
@@ -2,13 +2,14 @@ import { Action, isAction } from "../types"
 import { FetchMethod } from "../../http/fetch_request"
 import { FetchResponse } from "../../http/fetch_response"
 import { FormSubmission } from "./form_submission"
-import { expandURL, getAnchor, getRequestURL, Locatable, locationIsVisitable } from "../url"
+import { expandURL, getAnchor, getRequestURL, Locatable } from "../url"
 import { getAttribute } from "../../util"
 import { Visit, VisitDelegate, VisitOptions } from "./visit"
 import { PageSnapshot } from "./page_snapshot"
 
 export type NavigatorDelegate = VisitDelegate & {
   allowsVisitingLocationWithAction(location: URL, action?: Action): boolean
+  locationIsVisitable(location: URL, rootLocation: URL): boolean
   visitProposedToLocation(location: URL, options: Partial<VisitOptions>): void
   notifyApplicationAfterVisitingSamePageLocation(oldURL: URL, newURL: URL): void
 }
@@ -24,7 +25,7 @@ export class Navigator {
 
   proposeVisit(location: URL, options: Partial<VisitOptions> = {}) {
     if (this.delegate.allowsVisitingLocationWithAction(location, options.action)) {
-      if (locationIsVisitable(location, this.view.snapshot.rootLocation)) {
+      if (this.delegate.locationIsVisitable(location, this.view.snapshot.rootLocation)) {
         this.delegate.visitProposedToLocation(location, options)
       } else {
         window.location.href = location.toString()
diff --git a/src/core/frames/frame_controller.ts b/src/core/frames/frame_controller.ts
index 9aad69841..46e3cdc91 100644
--- a/src/core/frames/frame_controller.ts
+++ b/src/core/frames/frame_controller.ts
@@ -6,7 +6,7 @@ import { clearBusyState, getAttribute, parseHTMLDocument, markAsBusy } from "../
 import { FormSubmission, FormSubmissionDelegate } from "../drive/form_submission"
 import { Snapshot } from "../snapshot"
 import { ViewDelegate } from "../view"
-import { getAction, expandURL, urlsAreEqual, locationIsVisitable } from "../url"
+import { getAction, expandURL, urlsAreEqual } from "../url"
 import { FormInterceptor, FormInterceptorDelegate } from "./form_interceptor"
 import { FrameView } from "./frame_view"
 import { LinkInterceptor, LinkInterceptorDelegate } from "./link_interceptor"
@@ -326,7 +326,7 @@ export class FrameController
   private formActionIsVisitable(form: HTMLFormElement, submitter?: HTMLElement) {
     const action = getAction(form, submitter)
 
-    return locationIsVisitable(expandURL(action), this.rootLocation)
+    return session.locationIsVisitable(expandURL(action), this.rootLocation)
   }
 
   private shouldInterceptNavigation(element: Element, submitter?: HTMLElement) {
diff --git a/src/core/frames/frame_redirector.ts b/src/core/frames/frame_redirector.ts
index 8e41aea8e..fa7b9a23e 100644
--- a/src/core/frames/frame_redirector.ts
+++ b/src/core/frames/frame_redirector.ts
@@ -1,15 +1,18 @@
 import { FormInterceptor, FormInterceptorDelegate } from "./form_interceptor"
 import { FrameElement } from "../../elements/frame_element"
 import { LinkInterceptor, LinkInterceptorDelegate } from "./link_interceptor"
-import { expandURL, getAction, locationIsVisitable } from "../url"
+import { Session } from "../session"
+import { expandURL, getAction } from "../url"
 
 export class FrameRedirector implements LinkInterceptorDelegate, FormInterceptorDelegate {
   readonly element: Element
+  readonly session: Session
   readonly linkInterceptor: LinkInterceptor
   readonly formInterceptor: FormInterceptor
 
-  constructor(element: Element) {
+  constructor(element: Element, session: Session) {
     this.element = element
+    this.session = session
     this.linkInterceptor = new LinkInterceptor(this, element)
     this.formInterceptor = new FormInterceptor(this, element)
   }
@@ -52,7 +55,7 @@ export class FrameRedirector implements LinkInterceptorDelegate, FormInterceptor
     const meta = this.element.ownerDocument.querySelector<HTMLMetaElement>(`meta[name="turbo-root"]`)
     const rootLocation = expandURL(meta?.content ?? "/")
 
-    return this.shouldRedirect(form, submitter) && locationIsVisitable(action, rootLocation)
+    return this.shouldRedirect(form, submitter) && this.session.locationIsVisitable(action, rootLocation)
   }
 
   private shouldRedirect(element: Element, submitter?: HTMLElement) {
diff --git a/src/core/session.ts b/src/core/session.ts
index 55e37fa06..d9700fffb 100644
--- a/src/core/session.ts
+++ b/src/core/session.ts
@@ -5,7 +5,7 @@ import { FormSubmitObserver, FormSubmitObserverDelegate } from "../observers/for
 import { FrameRedirector } from "./frames/frame_redirector"
 import { History, HistoryDelegate } from "./drive/history"
 import { LinkClickObserver, LinkClickObserverDelegate } from "../observers/link_click_observer"
-import { getAction, expandURL, locationIsVisitable, Locatable } from "./url"
+import { getAction, getExtension, expandURL, isPrefixedBy, Locatable } from "./url"
 import { Navigator, NavigatorDelegate } from "./drive/navigator"
 import { PageObserver, PageObserverDelegate } from "../observers/page_observer"
 import { ScrollObserver } from "../observers/scroll_observer"
@@ -42,7 +42,7 @@ export class Session
   readonly scrollObserver = new ScrollObserver(this)
   readonly streamObserver = new StreamObserver(this)
 
-  readonly frameRedirector = new FrameRedirector(document.documentElement)
+  readonly frameRedirector = new FrameRedirector(document.documentElement, this)
 
   drive = true
   enabled = true
@@ -107,6 +107,14 @@ export class Session
     this.view.clearSnapshotCache()
   }
 
+  isVisitable(url: URL) {
+    return !!getExtension(url).match(/^(?:|\.(?:htm|html|xhtml|php))$/)
+  }
+
+  locationIsVisitable(location: URL, rootLocation: URL) {
+    return isPrefixedBy(location, rootLocation) && this.isVisitable(location)
+  }
+
   setProgressBarDelay(delay: number) {
     this.progressBarDelay = delay
   }
@@ -149,7 +157,7 @@ export class Session
   willFollowLinkToLocation(link: Element, location: URL) {
     return (
       this.elementDriveEnabled(link) &&
-      locationIsVisitable(location, this.snapshot.rootLocation) &&
+      this.locationIsVisitable(location, this.snapshot.rootLocation) &&
       this.applicationAllowsFollowingLinkToLocation(link, location)
     )
   }
@@ -225,7 +233,7 @@ export class Session
     return (
       this.elementDriveEnabled(form) &&
       (!submitter || this.formElementDriveEnabled(submitter)) &&
-      locationIsVisitable(expandURL(action), this.snapshot.rootLocation)
+      this.locationIsVisitable(expandURL(action), this.snapshot.rootLocation)
     )
   }
 
diff --git a/src/core/url.ts b/src/core/url.ts
index 2aa343276..5b68ecad4 100644
--- a/src/core/url.ts
+++ b/src/core/url.ts
@@ -24,19 +24,11 @@ export function getExtension(url: URL) {
   return (getLastPathComponent(url).match(/\.[^.]*$/) || [])[0] || ""
 }
 
-export function isHTML(url: URL) {
-  return !!getExtension(url).match(/^(?:|\.(?:htm|html|xhtml))$/)
-}
-
 export function isPrefixedBy(baseURL: URL, url: URL) {
   const prefix = getPrefix(url)
   return baseURL.href === expandURL(prefix).href || baseURL.href.startsWith(prefix)
 }
 
-export function locationIsVisitable(location: URL, rootLocation: URL) {
-  return isPrefixedBy(location, rootLocation) && isHTML(location)
-}
-
 export function getRequestURL(url: URL) {
   const anchor = getAnchor(url)
   return anchor != null ? url.href.slice(0, -(anchor.length + 1)) : url.href
diff --git a/src/tests/fixtures/visitable.html b/src/tests/fixtures/visitable.html
new file mode 100644
index 000000000..659a49e2a
--- /dev/null
+++ b/src/tests/fixtures/visitable.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Visitable</title>
+    <script src="/dist/turbo.es2017-umd.js" data-turbo-track="reload"></script>
+    <script src="/src/tests/fixtures/test.js"></script>
+  </head>
+  <body>
+    <h1>Visitable</h1>
+
+    <div>
+      <a id="link" href="/src/tests/fixtures/visitable.html">link</a>
+    </div>
+  </body>
+</html>
diff --git a/src/tests/functional/index.ts b/src/tests/functional/index.ts
index 2c5c469bd..c6903f259 100644
--- a/src/tests/functional/index.ts
+++ b/src/tests/functional/index.ts
@@ -15,3 +15,4 @@ export * from "./rendering_tests"
 export * from "./scroll_restoration_tests"
 export * from "./stream_tests"
 export * from "./visit_tests"
+export * from "./visitable_tests"
diff --git a/src/tests/functional/visitable_tests.ts b/src/tests/functional/visitable_tests.ts
new file mode 100644
index 000000000..3a1bcc536
--- /dev/null
+++ b/src/tests/functional/visitable_tests.ts
@@ -0,0 +1,33 @@
+import { TurboDriveTestCase } from "../helpers/turbo_drive_test_case"
+
+export class VisitableTests extends TurboDriveTestCase {
+  path = "/src/tests/fixtures/visitable.html"
+
+  async setup() {
+    await this.goToLocation(this.path)
+  }
+
+  async "test user-defined visitable URL"() {
+    await this.remote.execute(() => {
+      window.Turbo.session.isVisitable = url => true
+    })
+
+    this.clickSelector("#link")
+    await this.nextBody
+    this.assert.equal(await this.pathname, this.path)
+    this.assert.equal(await this.visitAction, "advance")
+  }
+
+  async "test user-defined unvisitable URL"() {
+    await this.remote.execute(() => {
+      window.Turbo.session.isVisitable = url => false
+    })
+
+    this.clickSelector("#link")
+    await this.nextBody
+    this.assert.equal(await this.pathname, this.path)
+    this.assert.equal(await this.visitAction, "load")
+  }
+}
+
+VisitableTests.registerSuite()