diff --git a/src/bidiMapper/modules/context/BrowsingContextImpl.ts b/src/bidiMapper/modules/context/BrowsingContextImpl.ts
index ab03243ebe..dd2b08d3af 100644
--- a/src/bidiMapper/modules/context/BrowsingContextImpl.ts
+++ b/src/bidiMapper/modules/context/BrowsingContextImpl.ts
@@ -73,6 +73,9 @@ export class BrowsingContextImpl {
   readonly #eventManager: EventManager;
   readonly #realmStorage: RealmStorage;
   #loaderId?: Protocol.Network.LoaderId;
+  // Used when no loaderId is available, e.g. for same-document navigations. Updated on
+  // each navigation.
+  #fakeNavigationId: string = uuidv4();
   #cdpTarget: CdpTarget;
   #maybeDefaultRealm?: Realm;
   readonly #logger?: LoggerFn;
@@ -333,6 +336,8 @@ export class BrowsingContextImpl {
       // previous page are detached and realms are destroyed.
       // Remove children from context.
       this.#deleteAllChildren();
+      // Reset the fake navigation ID.
+      this.#fakeNavigationId = uuidv4();
     });
 
     this.#cdpTarget.cdpClient.on('Page.navigatedWithinDocument', (params) => {
@@ -349,13 +354,15 @@ export class BrowsingContextImpl {
           method: ChromiumBidi.BrowsingContext.EventNames.FragmentNavigated,
           params: {
             context: this.id,
-            navigation: null,
+            navigation: this.#fakeNavigationId,
             timestamp,
             url: this.#url,
           },
         },
         this.id
       );
+      // Reset the fake navigation ID.
+      this.#fakeNavigationId = uuidv4();
     });
 
     this.#cdpTarget.cdpClient.on('Page.frameStartedLoading', (params) => {
@@ -368,6 +375,8 @@ export class BrowsingContextImpl {
           method: ChromiumBidi.BrowsingContext.EventNames.NavigationStarted,
           params: {
             context: this.id,
+            // No `navigation` available yet, but `fakeNavigationId` cannot be used, as it
+            // can be a real navigation.
             navigation: null,
             timestamp: BrowsingContextImpl.getTimestamp(),
             url: '',
@@ -414,7 +423,7 @@ export class BrowsingContextImpl {
               method: ChromiumBidi.BrowsingContext.EventNames.DomContentLoaded,
               params: {
                 context: this.id,
-                navigation: this.#loaderId ?? null,
+                navigation: this.#loaderId,
                 timestamp,
                 url: this.#url,
               },
@@ -431,7 +440,7 @@ export class BrowsingContextImpl {
               method: ChromiumBidi.BrowsingContext.EventNames.Load,
               params: {
                 context: this.id,
-                navigation: this.#loaderId ?? null,
+                navigation: this.#loaderId,
                 timestamp,
                 url: this.#url,
               },
@@ -667,9 +676,9 @@ export class BrowsingContextImpl {
 
     return {
       // Missing `loaderId` means same-document navigation. However, WebDriver BiDi spec
-      // requires a unique navigation ID for each navigation, so generate a new one.
-      // Note: this navigation is not shared with the network domain.
-      navigation: cdpNavigateResult.loaderId ?? uuidv4(),
+      // requires a unique navigation ID for each navigation, so use `fakeNavigationId`
+      // which is unique for each navigation.
+      navigation: cdpNavigateResult.loaderId ?? this.#fakeNavigationId,
       // Url can change due to redirect get the latest one.
       url: wait === BrowsingContext.ReadinessState.None ? url : this.#url,
     };