diff --git a/extensions/permissions/test/PermissionTestUtils.sys.mjs b/extensions/permissions/test/PermissionTestUtils.sys.mjs
index 84601376baec..84c5f63ecbd1 100644
--- a/extensions/permissions/test/PermissionTestUtils.sys.mjs
+++ b/extensions/permissions/test/PermissionTestUtils.sys.mjs
@@ -45,6 +45,20 @@ export let PermissionTestUtils = {
   add(subject, ...args) {
     return pm.addFromPrincipal(convertToPrincipal(subject), ...args);
   },
+  /**
+   * Add permission information for a given subject.
+   * Subject can be a principal, uri or origin string.
+   *
+   * This is a variant of add that allows specifying modification time.
+   *
+   * @see nsIPermissionManager for documentation
+   *
+   * @param {Ci.nsIPrincipal|Ci.nsIURI|string} subject
+   * @param {*} args
+   */
+  addWithModificationTime(subject, ...args) {
+    return pm.testAddFromPrincipalByTime(convertToPrincipal(subject), ...args);
+  },
   /**
    * Get all custom permissions for a given subject.
    * Subject can be a principal, uri or origin string.
diff --git a/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingProtection.cpp b/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingProtection.cpp
index 9e2f3f33ebf1..c39a3b3b5e48 100644
--- a/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingProtection.cpp
+++ b/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingProtection.cpp
@@ -438,6 +438,11 @@ BounceTrackingProtection::TestAddUserActivation(
   return stateGlobal->RecordUserActivation(host, aActivationTime);
 }
 
+NS_IMETHODIMP
+BounceTrackingProtection::TestMaybeMigrateUserInteractionPermissions() {
+  return MaybeMigrateUserInteractionPermissions();
+}
+
 RefPtr<BounceTrackingProtection::PurgeBounceTrackersMozPromise>
 BounceTrackingProtection::PurgeBounceTrackers() {
   // Prevent multiple purge operations from running at the same time.
diff --git a/toolkit/components/antitracking/bouncetrackingprotection/nsIBounceTrackingProtection.idl b/toolkit/components/antitracking/bouncetrackingprotection/nsIBounceTrackingProtection.idl
index 11634923339a..04a97784ae34 100644
--- a/toolkit/components/antitracking/bouncetrackingprotection/nsIBounceTrackingProtection.idl
+++ b/toolkit/components/antitracking/bouncetrackingprotection/nsIBounceTrackingProtection.idl
@@ -47,4 +47,10 @@ interface nsIBounceTrackingProtection : nsISupports {
 
     [implicit_jscontext]
     void testAddUserActivation(in jsval originAttributes, in ACString aSiteHost, in PRTime aActivationTime);
+
+    // Test helper to trigger user activation import from the permission
+    // manager. Will only import if the pref
+    // privacy.bounceTrackingProtection.hasMigratedUserActivationData is set to
+    // false.
+    void testMaybeMigrateUserInteractionPermissions();
 };
diff --git a/toolkit/components/antitracking/bouncetrackingprotection/test/xpcshell/test_bouncetracking_importUserActivationPermissions.js b/toolkit/components/antitracking/bouncetrackingprotection/test/xpcshell/test_bouncetracking_importUserActivationPermissions.js
new file mode 100644
index 000000000000..d04c114fc9c3
--- /dev/null
+++ b/toolkit/components/antitracking/bouncetrackingprotection/test/xpcshell/test_bouncetracking_importUserActivationPermissions.js
@@ -0,0 +1,150 @@
+/* Any copyright is dedicated to the Public Domain.
+https://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { PermissionTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PermissionTestUtils.sys.mjs"
+);
+
+const DOMAIN_A = "example.com";
+const SUB_DOMAIN_A = "sub." + DOMAIN_A;
+const DOMAIN_B = "example.org";
+const DOMAIN_C = "example.net";
+
+const ORIGIN_A = "https://" + DOMAIN_A;
+const ORIGIN_SUB_A = "https://" + SUB_DOMAIN_A;
+const ORIGIN_B = "https://" + DOMAIN_B;
+const ORIGIN_C = "https://" + DOMAIN_C;
+const ORIGIN_NON_HTTP = "file:///foo/bar.html";
+
+const OA_PBM = { privateBrowsingId: 1 };
+const PRINCIPAL_C_PBM = Services.scriptSecurityManager.createContentPrincipal(
+  Services.io.newURI(ORIGIN_C),
+  OA_PBM
+);
+
+let btp;
+let userActivationLifetimeSec = Services.prefs.getIntPref(
+  "privacy.bounceTrackingProtection.bounceTrackingActivationLifetimeSec"
+);
+
+function cleanup() {
+  btp.clearAll();
+  Services.perms.removeAll();
+  Services.prefs.setBoolPref(
+    "privacy.bounceTrackingProtection.hasMigratedUserActivationData",
+    false
+  );
+}
+
+add_setup(function () {
+  // Need a profile to data clearing calls.
+  do_get_profile();
+
+  btp = Cc["@mozilla.org/bounce-tracking-protection;1"].getService(
+    Ci.nsIBounceTrackingProtection
+  );
+
+  // Clean initial state.
+  cleanup();
+});
+
+add_task(async function test_user_activation_perm_migration() {
+  // Assert initial test state.
+  Assert.deepEqual(
+    btp.testGetUserActivationHosts({}),
+    [],
+    "No user activation hosts initially."
+  );
+  Assert.equal(
+    Services.perms.getAllByTypes(["storageAccessAPI"]).length,
+    0,
+    "No user activation permissions initially."
+  );
+
+  info("Add test user activation permissions.");
+
+  let now = Date.now();
+
+  // Non-expired permissions.
+  PermissionTestUtils.addWithModificationTime(
+    ORIGIN_A,
+    "storageAccessAPI",
+    Services.perms.ALLOW_ACTION,
+    now
+  );
+  PermissionTestUtils.addWithModificationTime(
+    ORIGIN_C,
+    "storageAccessAPI",
+    Services.perms.ALLOW_ACTION,
+    now - 1000
+  );
+
+  // A non expired permission for a subdomain of DOMAIN_A that has an older modification time.
+  PermissionTestUtils.addWithModificationTime(
+    ORIGIN_SUB_A,
+    "storageAccessAPI",
+    Services.perms.ALLOW_ACTION,
+    now - 500
+  );
+
+  // An expired permission.
+  PermissionTestUtils.addWithModificationTime(
+    ORIGIN_B,
+    "storageAccessAPI",
+    Services.perms.ALLOW_ACTION,
+    now - userActivationLifetimeSec * 1.2 * 1000
+  );
+
+  // A non-HTTP permission.
+  PermissionTestUtils.addWithModificationTime(
+    ORIGIN_NON_HTTP,
+    "storageAccessAPI",
+    Services.perms.ALLOW_ACTION,
+    now
+  );
+
+  // A permission for PBM. Ideally we'd test a more persistent permission type
+  // here with custom oa, but permission seperation by userContextId isn't
+  // enabled yet (Bug 1641584).
+  PermissionTestUtils.addWithModificationTime(
+    PRINCIPAL_C_PBM,
+    "storageAccessAPI",
+    Services.perms.ALLOW_ACTION,
+    now
+  );
+
+  info("Trigger migration.");
+  btp.testMaybeMigrateUserInteractionPermissions();
+
+  Assert.deepEqual(
+    btp.testGetUserActivationHosts({}).sort(),
+    [DOMAIN_A, DOMAIN_C].sort(),
+    "Should have imported the correct user activation flags."
+  );
+  Assert.deepEqual(
+    btp.testGetUserActivationHosts(OA_PBM).sort(),
+    [DOMAIN_C],
+    "Should have imported the correct user activation flags for PBM."
+  );
+
+  info("Reset the BTP user activation store");
+  btp.clearAll();
+
+  info("Trigger migration again.");
+  btp.testMaybeMigrateUserInteractionPermissions();
+
+  Assert.deepEqual(
+    btp.testGetUserActivationHosts({}),
+    [],
+    "Should not have imported the user activation flags again."
+  );
+  Assert.deepEqual(
+    btp.testGetUserActivationHosts(OA_PBM),
+    [],
+    "Should not have imported the user activation flags again for PBM."
+  );
+
+  cleanup();
+});
diff --git a/toolkit/components/antitracking/bouncetrackingprotection/test/xpcshell/xpcshell.toml b/toolkit/components/antitracking/bouncetrackingprotection/test/xpcshell/xpcshell.toml
index e21e6fabb2cc..8195ea7224ea 100644
--- a/toolkit/components/antitracking/bouncetrackingprotection/test/xpcshell/xpcshell.toml
+++ b/toolkit/components/antitracking/bouncetrackingprotection/test/xpcshell/xpcshell.toml
@@ -8,4 +8,6 @@ prefs = [
 
 ["test_bouncetracking_clearExpiredUserActivation.js"]
 
+["test_bouncetracking_importUserActivationPermissions.js"]
+
 ["test_bouncetracking_purge.js"]