diff --git a/moli-protocol/src/domains/page/tests/same_document_history.rs b/moli-protocol/src/domains/page/tests/same_document_history.rs
index b23a393d33..c80c67c89b 100644
--- a/moli-protocol/src/domains/page/tests/same_document_history.rs
+++ b/moli-protocol/src/domains/page/tests/same_document_history.rs
@@ -7,6 +7,7 @@ mod cross_origin_navigation;
 mod frame_attribute_ancestors;
 mod history_limits;
 mod hyperlink_navigation;
+mod native_request_urls;
 mod navigation_focus;
 mod navigation_inspector_output;
 mod navigation_window_reuse;
diff --git a/moli-protocol/src/domains/page/tests/same_document_history/native_request_urls.rs b/moli-protocol/src/domains/page/tests/same_document_history/native_request_urls.rs
new file mode 100644
index 0000000000..e5c90e8a23
--- /dev/null
+++ b/moli-protocol/src/domains/page/tests/same_document_history/native_request_urls.rs
@@ -0,0 +1,124 @@
+use super::*;
+use std::sync::{
+    Arc,
+    atomic::{AtomicUsize, Ordering},
+};
+
+const WORKER: &str = r#"
+addEventListener('fetch', event => {
+    if (new URL(event.request.url).pathname !== '/native-request/echo') return;
+    event.respondWith((async () => {
+        const original = event.request, url = original.url;
+        Object.defineProperty(original, 'url', {get() { throw new Error('public url getter'); }});
+        Object.defineProperty(original, 'toString', {value() { throw new Error('public toString'); }});
+        const constructors = [];
+        let copy;
+        for (const init of [undefined, {}, {cache:'no-store'}]) {
+            try {
+                const value = new Request(original, init);
+                constructors.push({url:value.url});
+                copy ||= value;
+            } catch (e) { constructors.push({error:e.name}); }
+        }
+        const forwarded = [];
+        for (const input of [original, copy]) {
+            if (!input) { forwarded.push({error:'no copy'}); continue; }
+            try {
+                const response = await fetch(input);
+                forwarded.push({status:response.status, data:await response.json()});
+            } catch (e) { forwarded.push({error:e.name}); }
+        }
+        const refused = [];
+        for (const input of [url, {url}]) {
+            try { await fetch(input); refused.push('allowed'); } catch (e) { refused.push(e.name); }
+        }
+        const cache = await caches.open('native-request-url');
+        await cache.put(original, new Response('seed'));
+        return new Response(JSON.stringify({url, constructors, forwarded, refused}));
+    })());
+});
+"#;
+
+#[tokio::test(flavor = "multi_thread")]
+async fn native_request_urls_are_forwarded_by_window_and_worker_fetch() {
+    run_history_test(async {
+        let requests = Arc::new(AtomicUsize::new(0));
+        let observed = requests.clone();
+        let routes = axum::Router::new()
+            .route("/request-worker.js", axum::routing::get(|| async {
+                ([(axum::http::header::CONTENT_TYPE, "application/javascript")], WORKER)
+            }))
+            .route("/native-request/frame.html", axum::routing::get(|| async {
+                ([(axum::http::header::CONTENT_TYPE, "text/html")], "<!doctype html><body>controlled</body>")
+            }))
+            .route("/native-request/echo", axum::routing::get(move || {
+                let requests = observed.clone();
+                async move {
+                    requests.fetch_add(1, Ordering::SeqCst);
+                    ([(axum::http::header::CACHE_CONTROL, "no-store")], axum::Json(json!({"network":true})))
+                }
+            }));
+        let mut page = SameDocumentPage::with_routes(routes).await;
+        let report = page.evaluate(r#"(async () => {
+            const registration = await navigator.serviceWorker.register('/request-worker.js', {scope:'/native-request/'});
+            const tick = () => new Promise(resolve => setTimeout(resolve,10));
+            for (let n=0; n<500 && registration.active?.state !== 'activated'; ++n) await tick();
+            if (registration.active?.state !== 'activated') throw new Error('worker not activated');
+            const frame = document.createElement('iframe');
+            const loaded = new Promise(resolve => frame.onload = resolve);
+            frame.src = '/native-request/frame.html';
+            document.body.appendChild(frame);
+            await loaded;
+            if (!frame.contentWindow.navigator.serviceWorker.controller) throw new Error('missing controller');
+            const worker = await new Promise((resolve,reject) => {
+                const xhr = new frame.contentWindow.XMLHttpRequest();
+                xhr.open('GET','/native-request/echo',true,'alice','secret');
+                xhr.onload = () => { try { resolve(JSON.parse(xhr.responseText)); } catch(e) { reject(e); } };
+                xhr.onerror = () => reject(new Error('controlled XHR failed'));
+                xhr.send();
+            });
+            const cache = await caches.open('native-request-url');
+            const keys = await cache.keys();
+            if (keys.length !== 1) throw new Error('missing native cache key');
+            const key = keys[0], url = key.url;
+            Object.defineProperty(key, 'url', {get() { throw new Error('public key url getter'); }});
+            Object.defineProperty(key, 'toString', {value() { throw new Error('public key toString'); }});
+            const constructors = [];
+            let copy;
+            for (const init of [undefined, {}, {cache:'no-store'}]) {
+                try { const value = new Request(key,init); constructors.push({url:value.url}); copy ||= value; }
+                catch(e) { constructors.push({error:e.name}); }
+            }
+            const forwarded = [];
+            for (const input of [key,copy]) {
+                if (!input) { forwarded.push({error:'no copy'}); continue; }
+                try {
+                    const response = await fetch(input);
+                    forwarded.push({status:response.status,data:await response.json()});
+                } catch(e) { forwarded.push({error:e.name}); }
+            }
+            const refused = [];
+            for (const input of [url,{url}]) {
+                try { new Request(input); refused.push('allowed'); } catch(e) { refused.push(e.name); }
+                try { await fetch(input); refused.push('allowed'); } catch(e) { refused.push(e.name); }
+            }
+            frame.remove();
+            await registration.unregister();
+            await caches.delete('native-request-url');
+            return {worker,window:{url,constructors,forwarded,refused}};
+        })()"#).await;
+        let expected_url = page.base_url.replace("http://", "http://alice:secret@").replace("/history.html", "/native-request/echo");
+        for realm in ["worker", "window"] {
+            assert_eq!(report[realm]["url"], expected_url, "{realm}: {report}");
+            assert_eq!(report[realm]["constructors"], json!([
+                {"url":expected_url},{"url":expected_url},{"url":expected_url}
+            ]), "{realm}: {report}");
+            assert_eq!(report[realm]["forwarded"], json!([
+                {"status":200,"data":{"network":true}}, {"status":200,"data":{"network":true}}
+            ]), "{realm}: {report}");
+        }
+        assert_eq!(report["worker"]["refused"], json!(["TypeError","TypeError"]));
+        assert_eq!(report["window"]["refused"], json!(["TypeError","TypeError","TypeError","TypeError"]));
+        assert_eq!(requests.load(Ordering::SeqCst),4, "rejected external inputs must not reach HTTP: {report}");
+    }).await;
+}
diff --git a/moli-renderer-v8/src/network_host.rs b/moli-renderer-v8/src/network_host.rs
index 36cdda359f..4e7d5a773d 100644
--- a/moli-renderer-v8/src/network_host.rs
+++ b/moli-renderer-v8/src/network_host.rs
@@ -160,7 +160,7 @@ pub(crate) use self::preload::{
 };
 pub(crate) use self::request::build_service_worker_request_object;
 pub(crate) use self::request::{
-    FetchArgs, RequestInfo, parse_fetch_init, parse_request_redirect_mode_label,
+    FetchArgs, RequestInfo, RequestInputUrl, parse_fetch_init, parse_request_redirect_mode_label,
     request_object_credentials_mode, validate_fetch_body,
 };
 pub(crate) use self::request::{FetchArgumentError, convert_fetch_arguments};
@@ -172,7 +172,6 @@ pub(crate) use self::request::{
     mark_request_input_body_used_for_fetch, request_body_already_used_error,
     request_headers_guard_for_mode, try_resolve_request_constructor_url_for_base,
     try_resolve_request_constructor_url_for_child, validate_request_method_body,
-    validate_request_url_credentials,
 };
 pub(in crate::network_host) use self::request_scope::{
     XHR_CHILD_CONTEXT_HANDLE_SLOT, active_subresource_network_partition_key,
diff --git a/moli-renderer-v8/src/network_host/fetch/bindings/request.rs b/moli-renderer-v8/src/network_host/fetch/bindings/request.rs
index ec9226e8c1..4fa0e4619f 100644
--- a/moli-renderer-v8/src/network_host/fetch/bindings/request.rs
+++ b/moli-renderer-v8/src/network_host/fetch/bindings/request.rs
@@ -140,8 +140,8 @@ pub(super) fn prepare_window_fetch_request<'s>(
     let cors_preflight_request_headers = request_headers.clone();
     let request_headers =
         merge_byte_string_request_headers(host.extra_http_headers(), &request_headers);
-    let resolved_url = resolve_context_url(&base_url, &parsed.url, None)?;
-    validate_request_url_credentials(&resolved_url)?;
+    let resolved_url = resolve_context_url(&base_url, parsed.url.as_str(), None)?;
+    parsed.url.validate_credentials(&resolved_url)?;
     let referrer = parsed
         .init_validation
         .validate(scope, parsed.request_mode.as_ref(), &parsed.cache)?
diff --git a/moli-renderer-v8/src/network_host/fetch/input.rs b/moli-renderer-v8/src/network_host/fetch/input.rs
index 898b69c093..d32a3ba6cd 100644
--- a/moli-renderer-v8/src/network_host/fetch/input.rs
+++ b/moli-renderer-v8/src/network_host/fetch/input.rs
@@ -3,7 +3,7 @@ use crate::webidl;
 use std::str::FromStr;
 
 pub(super) struct ParsedWindowFetchInput {
-    pub(super) url: String,
+    pub(super) url: RequestInputUrl,
     pub(super) blob_url_entry: Option<CapturedBlobUrl>,
     pub(super) method: String,
     pub(super) body: Option<bytes::Bytes>,
diff --git a/moli-renderer-v8/src/network_host/request.rs b/moli-renderer-v8/src/network_host/request.rs
index 1e16a90e24..a2ded80ffd 100644
--- a/moli-renderer-v8/src/network_host/request.rs
+++ b/moli-renderer-v8/src/network_host/request.rs
@@ -20,9 +20,9 @@ pub(crate) use self::init::{
 };
 pub(crate) use self::init::{parse_request_redirect_mode_label, request_redirect_mode_label};
 pub(crate) use self::input::{
-    RequestInfo, mark_request_input_body_used_for_fetch, request_body_already_used_error,
-    request_headers_guard_for_mode, try_resolve_request_constructor_url_for_base,
-    try_resolve_request_constructor_url_for_child, validate_request_method_body,
-    validate_request_url_credentials,
+    RequestInfo, RequestInputUrl, mark_request_input_body_used_for_fetch,
+    request_body_already_used_error, request_headers_guard_for_mode,
+    try_resolve_request_constructor_url_for_base, try_resolve_request_constructor_url_for_child,
+    validate_request_method_body,
 };
 pub(in crate::network_host) use self::input::{RequestMethodError, normalize_request_method};
diff --git a/moli-renderer-v8/src/network_host/request/bindings/init.rs b/moli-renderer-v8/src/network_host/request/bindings/init.rs
index 4cf8d79cb3..acd21f23dc 100644
--- a/moli-renderer-v8/src/network_host/request/bindings/init.rs
+++ b/moli-renderer-v8/src/network_host/request/bindings/init.rs
@@ -2,7 +2,6 @@ use super::super::init::RequestInitMembers;
 use super::super::input::{
     normalize_fetch_request_method, request_body_already_used_error,
     request_headers_guard_for_mode, request_method_allows_body,
-    try_resolve_request_constructor_url_for_scope, validate_request_url_credentials,
 };
 use super::super::*;
 use crate::webidl;
@@ -40,15 +39,8 @@ pub(super) fn request_initial_state<'s>(
     child_handle: Option<crate::document_runtime::DomHandle>,
     base_url: Option<url::Url>,
 ) -> Result<RequestConstructionState, webidl::WebIdlError> {
-    let (url_str, inherited, input_object) = input.materialize(scope)?;
-    let url_resolved =
-        try_resolve_request_constructor_url_for_scope(scope, &url_str, child_handle, base_url)
-            .map_err(|_| {
-                webidl::WebIdlError::custom_message("Failed to construct 'Request': invalid URL")
-            })?;
-    if let Ok(url) = url::Url::parse(&url_resolved) {
-        validate_request_url_credentials(&url)?;
-    }
+    let (url, inherited, input_object) = input.materialize(scope)?;
+    let url_resolved = url.into_constructor_url(scope, child_handle, base_url)?;
     let method = inherited
         .as_ref()
         .map(|snapshot| snapshot.method.clone())
diff --git a/moli-renderer-v8/src/network_host/request/input.rs b/moli-renderer-v8/src/network_host/request/input.rs
index d3ed57630c..76b4317f27 100644
--- a/moli-renderer-v8/src/network_host/request/input.rs
+++ b/moli-renderer-v8/src/network_host/request/input.rs
@@ -113,27 +113,83 @@ impl<'s> webidl::WebIdlConverter<'s> for RequestInfo<'s> {
     }
 }
 
+/// Keep native URL authority through constructor and fetch preparation.
+/// The request-like compatibility extension still uses ordinary URL validation.
+pub(crate) enum RequestInputUrl {
+    Native(String),
+    Converted(String),
+}
+
+impl RequestInputUrl {
+    pub(crate) fn as_str(&self) -> &str {
+        match self {
+            Self::Native(url) | Self::Converted(url) => url,
+        }
+    }
+
+    pub(crate) fn validate_credentials(&self, parsed: &Url) -> Result<(), webidl::WebIdlError> {
+        match self {
+            Self::Native(_) => Ok(()),
+            Self::Converted(_) => validate_request_url_credentials(parsed),
+        }
+    }
+
+    pub(crate) fn into_constructor_url(
+        self,
+        scope: &mut v8::PinScope<'_, '_>,
+        child_handle: Option<crate::document_runtime::DomHandle>,
+        base_url: Option<Url>,
+    ) -> Result<String, webidl::WebIdlError> {
+        match self {
+            Self::Native(url) => Ok(url),
+            Self::Converted(url) => {
+                let resolved = try_resolve_request_constructor_url_for_scope(
+                    scope,
+                    &url,
+                    child_handle,
+                    base_url,
+                )
+                .map_err(|_| {
+                    webidl::WebIdlError::custom_message(
+                        "Failed to construct 'Request': invalid URL",
+                    )
+                })?;
+                if let Ok(parsed) = Url::parse(&resolved) {
+                    validate_request_url_credentials(&parsed)?;
+                }
+                Ok(resolved)
+            }
+        }
+    }
+}
+
 impl<'s> RequestInfo<'s> {
     pub(crate) fn materialize(
         self,
         scope: &mut v8::PinScope<'s, '_>,
     ) -> Result<
         (
-            String,
+            RequestInputUrl,
             Option<RequestInputSnapshot>,
             Option<v8::Local<'s, v8::Object>>,
         ),
         webidl::WebIdlError,
     > {
         match self {
-            Self::Url(url) => Ok((url, None, None)),
-            Self::Legacy(source, snapshot) => {
-                Ok((snapshot.url.clone(), Some(*snapshot), Some(source)))
-            }
+            Self::Url(url) => Ok((RequestInputUrl::Converted(url), None, None)),
+            Self::Legacy(source, snapshot) => Ok((
+                RequestInputUrl::Converted(snapshot.url.clone()),
+                Some(*snapshot),
+                Some(source),
+            )),
             Self::Native(source) => {
                 let snapshot = request_input_snapshot_for_constructor(scope, source.into())?
                     .expect("native Request snapshot");
-                Ok((snapshot.url.clone(), Some(snapshot), Some(source)))
+                Ok((
+                    RequestInputUrl::Native(snapshot.url.clone()),
+                    Some(snapshot),
+                    Some(source),
+                ))
             }
         }
     }
@@ -424,7 +480,7 @@ fn object_bool_property(
         .map(|value| value.boolean_value(scope))
 }
 
-pub(crate) fn validate_request_url_credentials(url: &url::Url) -> Result<(), webidl::WebIdlError> {
+fn validate_request_url_credentials(url: &url::Url) -> Result<(), webidl::WebIdlError> {
     if !url.username().is_empty() || url.password().is_some_and(|value| !value.is_empty()) {
         return Err(webidl::WebIdlError::custom_message(
             "Request URL must not include credentials",
diff --git a/moli-renderer-v8/src/worker/global_scope/fetch.rs b/moli-renderer-v8/src/worker/global_scope/fetch.rs
index c44e387f4d..bec3f40d13 100644
--- a/moli-renderer-v8/src/worker/global_scope/fetch.rs
+++ b/moli-renderer-v8/src/worker/global_scope/fetch.rs
@@ -2405,14 +2405,14 @@ pub(in crate::worker) fn resolve_worker_fetch_input<'s>(
             init.validation,
         )
     };
-    let resolved_url = resolve_context_url(base_url, &url_input, None)?;
+    let resolved_url = resolve_context_url(base_url, url_input.as_str(), None)?;
     crate::network_host::validate_fetch_body(
         body.is_some() || body_stream.is_some(),
         has_stream_body,
         &method,
         request_mode,
     )?;
-    crate::network_host::validate_request_url_credentials(&resolved_url)?;
+    url_input.validate_credentials(&resolved_url)?;
     if let Some(referrer) =
         init_validation.validate(scope, request_mode.as_ref(), &metadata.cache)?
     {
diff --git a/moli-renderer-v8/src/worker/thread/tests/lifecycle.rs b/moli-renderer-v8/src/worker/thread/tests/lifecycle.rs
index 0ca140d75b..0f377b5e50 100644
--- a/moli-renderer-v8/src/worker/thread/tests/lifecycle.rs
+++ b/moli-renderer-v8/src/worker/thread/tests/lifecycle.rs
@@ -199,6 +199,7 @@ mod client_lifecycle_and_sync;
 mod fetch_abort_reasons;
 mod fetch_events_and_messages;
 mod fetch_request_headers;
+mod fetch_request_urls;
 mod keepalive_fetch;
 mod messages_clients_and_windows;
 mod worker_and_fetch_lifecycle;
diff --git a/moli-renderer-v8/src/worker/thread/tests/lifecycle/fetch_request_urls.rs b/moli-renderer-v8/src/worker/thread/tests/lifecycle/fetch_request_urls.rs
new file mode 100644
index 0000000000..9a346cd784
--- /dev/null
+++ b/moli-renderer-v8/src/worker/thread/tests/lifecycle/fetch_request_urls.rs
@@ -0,0 +1,64 @@
+use super::*;
+
+#[tokio::test]
+async fn native_request_url_copy_preserves_credentials_and_upload_body() {
+    ensure_v8();
+    let mut handle = spawn_service_worker_for_test(
+        r#"
+        let attempt = 0;
+        addEventListener('fetch', event => event.respondWith((async () => {
+            const original = event.request;
+            const url = original.url;
+            const variant = attempt++;
+            Object.defineProperty(original, 'url', {get() { throw new Error('public url getter'); }});
+            Object.defineProperty(original, 'toString', {value() { throw new Error('public toString'); }});
+            try {
+                const copy = variant === 0 ? new Request(original) :
+                    new Request(original, variant === 1 ? {} : {cache:'no-store'});
+                const body = await copy.text();
+                copy.headers.set('accept', 'changed');
+                const rejected = input => {
+                    try { new Request(input); return 'allowed'; } catch (e) { return e.name; }
+                };
+                return new Response(JSON.stringify({
+                    url:copy.url, body, used:copy.bodyUsed,
+                    mode:copy.mode, credentials:copy.credentials, cache:copy.cache,
+                    referrer:copy.referrer, signal:copy.signal instanceof AbortSignal,
+                    headers:[original.headers.get('accept'), copy.headers.get('accept')],
+                    rejected:[rejected(url), rejected({url})]
+                }));
+            } catch (e) {
+                return new Response(JSON.stringify({error:e.name, message:e.message}));
+            }
+        })()));
+        "#,
+    );
+    let url = "https://alice:secret@example.test/app/data.txt";
+    for (id, changed) in [(940, false), (941, false), (942, true)] {
+        let mut request = service_worker_fetch_request_for_test();
+        request.url = url::Url::parse(url).unwrap();
+        request.method = "POST".into();
+        request.body = Some(bytes::Bytes::from_static(b"native request body"));
+        request.credentials_mode = moli_fetch::RequestCredentialsMode::Include;
+        request.metadata.referrer = "https://example.test/from".into();
+        let completion =
+            dispatch_service_worker_fetch_event_with_request_for_test(&mut handle, id, request)
+                .await;
+        let ServiceWorkerFetchResult::Response(response) = completion.result else {
+            panic!("expected native Request copy observations");
+        };
+        let observed: serde_json::Value = serde_json::from_slice(&response.body).unwrap();
+        assert_eq!(
+            observed,
+            serde_json::json!({
+                "url":url, "body":"native request body", "used":true,
+                "mode":"cors", "credentials":"include",
+                "cache":if changed {"no-store"} else {"default"},
+                "referrer":if changed {"about:client"} else {"https://example.test/from"},
+                "signal":true, "headers":["text/plain","changed"],
+                "rejected":["TypeError","TypeError"]
+            })
+        );
+    }
+    handle.terminate_and_join();
+}