diff --git a/moli-benchmark/wpt-cross-current/passed-cases.txt b/moli-benchmark/wpt-cross-current/passed-cases.txt
index 7e7c53cd45..0dde3c9fe4 100644
--- a/moli-benchmark/wpt-cross-current/passed-cases.txt
+++ b/moli-benchmark/wpt-cross-current/passed-cases.txt
@@ -6437,6 +6437,7 @@ html/browsers/history/the-location-interface/location_reload.html
 html/browsers/history/the-location-interface/location_reload_javascript_url.html
 html/browsers/history/the-location-interface/location_replace.html
 html/browsers/history/the-location-interface/location_search.html
+html/browsers/history/the-location-interface/no-browsing-context.window.js?moli-wpt-script=window
 html/browsers/history/the-location-interface/reload_document_write.html
 html/browsers/history/the-location-interface/replace-with-nested-iframe.html
 html/browsers/history/the-location-interface/security_location_0.htm
diff --git a/moli-core/tests/fixtures/retained-child-window.js b/moli-core/tests/fixtures/retained-child-window.js
index 326ad99fe4..e034c3a101 100644
--- a/moli-core/tests/fixtures/retained-child-window.js
+++ b/moli-core/tests/fixtures/retained-child-window.js
@@ -57,7 +57,8 @@
     await tick();
     check(mode + ':retired-timer-inactive', () => timerCalls, 0);
     check(mode + ':document', () => win.document === doc, true);
-    check(mode + ':location', () => win.location.href, url);
+    // With no relevant Document, Location exposes about:blank; the retained Document keeps its URL.
+    check(mode + ':location', () => win.location.href, 'about:blank');
     result.observations.push({mode, defaultViewIsNull: doc.defaultView === null});
     check(mode + ':own-data', () => win.retainedMarker === marker, true);
     check(mode + ':intrinsic', () => win.Event === eventConstructor, true);
diff --git a/moli-renderer-v8/src/context_bootstrap/location_navigation.rs b/moli-renderer-v8/src/context_bootstrap/location_navigation.rs
index e3bd740698..2bf9593406 100644
--- a/moli-renderer-v8/src/context_bootstrap/location_navigation.rs
+++ b/moli-renderer-v8/src/context_bootstrap/location_navigation.rs
@@ -1,6 +1,6 @@
 use super::location_runtime::{
-    is_same_document_fragment_navigation, location_href_slot, resolve_location_navigation_target,
-    sync_location_object,
+    is_same_document_fragment_navigation, location_has_relevant_document, location_href_slot,
+    resolve_location_navigation_target, sync_location_object,
 };
 use super::navigation_activation::{clear_navigation_transition, install_navigation_transition};
 use super::navigation_callbacks::cancel_active_intercepted_same_document_navigation;
@@ -276,6 +276,11 @@ fn navigate_location_object_with_source_element_and_child_navigate_event<'s>(
     source_element: Option<v8::Local<'s, v8::Object>>,
     options: LocationNavigationOptions,
 ) {
+    // The Location setters and methods return before URL parsing when their
+    // relevant Document is null, including when argument conversion removed it.
+    if !location_has_relevant_document(scope, location) {
+        return;
+    }
     let LocationNavigationOptions {
         dispatch_child_navigate_event_for_all_kinds,
         force_exact_same_document_navigation,
diff --git a/moli-renderer-v8/src/context_bootstrap/location_runtime.rs b/moli-renderer-v8/src/context_bootstrap/location_runtime.rs
index 63a6e192d5..43f37ce973 100644
--- a/moli-renderer-v8/src/context_bootstrap/location_runtime.rs
+++ b/moli-renderer-v8/src/context_bootstrap/location_runtime.rs
@@ -18,7 +18,7 @@ pub(in crate::context_bootstrap) use access::{location_target, wrap_location_obj
 pub(super) use install::{
     build_location_constructor_template, build_location_runtime_object,
     install_location_runtime_state, location_belongs_to_current_local_window,
-    location_owner_has_current_realm,
+    location_has_relevant_document, location_owner_has_current_realm,
 };
 pub(super) use navigation::{
     is_same_document_fragment_navigation, resolve_location_navigation_target,
diff --git a/moli-renderer-v8/src/context_bootstrap/location_runtime/access.rs b/moli-renderer-v8/src/context_bootstrap/location_runtime/access.rs
index 8dc5d0a096..0ee185cf82 100644
--- a/moli-renderer-v8/src/context_bootstrap/location_runtime/access.rs
+++ b/moli-renderer-v8/src/context_bootstrap/location_runtime/access.rs
@@ -231,7 +231,7 @@ pub(super) fn require_entry_origin<'s>(
     scope: &mut v8::PinScope<'s, '_>,
     object: v8::Local<'s, v8::Object>,
 ) -> bool {
-    if !super::install::location_belongs_to_current_local_window(scope, object) {
+    if !super::install::location_has_relevant_document(scope, object) {
         return true;
     }
     let entry = scope.get_entered_or_microtask_context();
diff --git a/moli-renderer-v8/src/context_bootstrap/location_runtime/helpers.rs b/moli-renderer-v8/src/context_bootstrap/location_runtime/helpers.rs
index da1fb2828c..5c59824b42 100644
--- a/moli-renderer-v8/src/context_bootstrap/location_runtime/helpers.rs
+++ b/moli-renderer-v8/src/context_bootstrap/location_runtime/helpers.rs
@@ -30,7 +30,24 @@ pub(super) fn parsed_location_url<'s>(
     scope: &mut v8::PinScope<'s, '_>,
     object: v8::Local<'s, v8::Object>,
 ) -> Option<url::Url> {
-    location_href_slot(scope, object).and_then(|href| url::Url::parse(&href).ok())
+    location_url(scope, object).and_then(|href| url::Url::parse(&href).ok())
+}
+
+pub(super) fn location_url<'s>(
+    scope: &mut v8::PinScope<'s, '_>,
+    object: v8::Local<'s, v8::Object>,
+) -> Option<String> {
+    let href = require_location_href_slot(scope, object)?;
+    // A retained Location has no relevant Document after its Window loses its
+    // browsing context. Its URL is then about:blank, independent of the old
+    // Document's URL or any new Window created for the same iframe element.
+    Some(
+        if super::install::location_has_relevant_document(scope, object) {
+            href
+        } else {
+            "about:blank".to_owned()
+        },
+    )
 }
 
 pub(super) fn require_location_href_slot<'s>(
diff --git a/moli-renderer-v8/src/context_bootstrap/location_runtime/install.rs b/moli-renderer-v8/src/context_bootstrap/location_runtime/install.rs
index 0cea411d9c..26f5157fc2 100644
--- a/moli-renderer-v8/src/context_bootstrap/location_runtime/install.rs
+++ b/moli-renderer-v8/src/context_bootstrap/location_runtime/install.rs
@@ -345,6 +345,37 @@ pub(in crate::context_bootstrap) fn location_belongs_to_current_local_window<'s>
     })
 }
 
+pub(in crate::context_bootstrap) fn location_has_relevant_document<'s>(
+    scope: &mut v8::PinScope<'s, '_>,
+    location: v8::Local<'s, v8::Object>,
+) -> bool {
+    let owner = runtime_window_owner(scope, location);
+    let Some(dispatch_scope) = runtime_window_dispatch_scope(scope, owner) else {
+        return false;
+    };
+    let Some(host_ptr) = context_host_ptr_from_global_bridge(scope) else {
+        return false;
+    };
+    let host = unsafe { &*host_ptr };
+    match dispatch_scope {
+        crate::native_bridge::OwnerDispatchScope::Top => owner
+            .get_creation_context(scope)
+            .and_then(|context| host.window_execution_context_identity_for_access_check(context))
+            .is_some_and(|identity| host.window_execution_context_identity_is_current(identity)),
+        crate::native_bridge::OwnerDispatchScope::Child(_) => {
+            // The same iframe element can acquire a different LocalWindow.
+            // A Location retained from the old Window must remain inactive.
+            location_belongs_to_current_local_window(scope, location)
+        }
+        crate::native_bridge::OwnerDispatchScope::LightweightPopup(popup_id) => {
+            // Popup shells share the opener realm. Their own document record,
+            // rather than that realm, determines when close destroys them.
+            host.current_lightweight_popup_document_owner(popup_id)
+                .is_some()
+        }
+    }
+}
+
 pub(in crate::context_bootstrap) fn location_owner_has_current_realm<'s>(
     scope: &mut v8::PinScope<'s, '_>,
     owner: v8::Local<'s, v8::Object>,
@@ -446,7 +477,7 @@ fn location_attribute_getter<'s>(
     {
         return;
     }
-    let Some(current_href) = require_location_href_slot(scope, holder) else {
+    let Some(current_href) = super::helpers::location_url(scope, holder) else {
         return;
     };
     match attribute {
@@ -471,8 +502,8 @@ fn location_attribute_getter<'s>(
             set_return_string(scope, rv, &search);
         }
         LocationAttribute::Pathname => {
-            let pathname = location_href_slot(scope, holder)
-                .and_then(|href| url::Url::parse(&href).ok())
+            let pathname = url::Url::parse(&current_href)
+                .ok()
                 .map(|url| url.path().to_owned())
                 .unwrap_or_default();
             set_return_string(scope, rv, &pathname);
@@ -538,6 +569,11 @@ fn location_writable_attribute_setter_callback<'s>(
     let Some(value) = v8_value_to_string(scope, args.get(0)) else {
         return;
     };
+    // Conversion can itself remove the iframe, so check the relevant Document
+    // afterwards and before component parsing or navigation side effects.
+    if !location_has_relevant_document(scope, holder) {
+        return;
+    }
     if !matches!(attribute, LocationAttribute::Href)
         && !super::access::require_entry_origin(scope, holder)
     {
diff --git a/moli-renderer-v8/src/context_bootstrap/location_runtime/methods.rs b/moli-renderer-v8/src/context_bootstrap/location_runtime/methods.rs
index 2e72ab101c..a307edaebb 100644
--- a/moli-renderer-v8/src/context_bootstrap/location_runtime/methods.rs
+++ b/moli-renderer-v8/src/context_bootstrap/location_runtime/methods.rs
@@ -88,7 +88,7 @@ pub(super) fn location_to_string_callback<'s>(
     {
         return;
     }
-    let Some(href) = require_location_href_slot(scope, args.this()) else {
+    let Some(href) = super::helpers::location_url(scope, args.this()) else {
         return;
     };
     set_return_string(scope, &mut rv, &href);
diff --git a/moli-renderer-v8/src/script_vm/tests/retained_child_window.rs b/moli-renderer-v8/src/script_vm/tests/retained_child_window.rs
index 4b2decabcc..c4f8354370 100644
--- a/moli-renderer-v8/src/script_vm/tests/retained_child_window.rs
+++ b/moli-renderer-v8/src/script_vm/tests/retained_child_window.rs
@@ -1,5 +1,59 @@
 use super::*;
 
+#[tokio::test(flavor = "current_thread")]
+async fn inactive_locations_have_blank_urls_and_cannot_navigate() {
+    let server = StaticHttpServer::spawn_with_bodies(vec![
+        "<!doctype html><body>Location lifecycle target</body>".to_owned(); 4
+    ])
+    .await;
+    let loader = static_http_loader([server.resolve_entry("www.example.test")]);
+    let parent_url = server.url_for_host("www.example.test", "/page.html");
+    let mut vm = new_storage_page_task_executor_test_vm_with_loader(parent_url.as_str(), &loader);
+    let script = include_str!(concat!(
+        env!("CARGO_MANIFEST_DIR"),
+        "/tests/fixtures/inactive-location.js"
+    ));
+    vm.exec(
+        &format!(
+            r#"
+if (!document.documentElement) document.appendChild(document.createElement('html'));
+if (!document.body) document.documentElement.appendChild(document.createElement('body'));
+globalThis.__inactiveLocationResult = null;
+({script})().then(
+  result => {{ globalThis.__inactiveLocationResult = result; }},
+  error => {{ globalThis.__inactiveLocationResult = {{error: String(error)}}; }}
+);
+"#,
+        ),
+        None,
+    )
+    .expect("inactive Location probe should start");
+    advance_page_task_executor_until_eval_equals(
+        &mut vm,
+        &loader,
+        "String(__inactiveLocationResult !== null)",
+        "true",
+        "inactive Location probe should finish",
+    )
+    .await;
+    let result: serde_json::Value = serde_json::from_str(
+        &vm.eval("JSON.stringify(__inactiveLocationResult)")
+            .expect("inactive Location observations"),
+    )
+    .unwrap();
+    assert_eq!(result["checks"], 295, "{result}");
+    assert_eq!(result["failures"], serde_json::json!([]), "{result}");
+    assert_eq!(
+        server.finish_targets().await,
+        vec![
+            "/removed.html?query=one",
+            "/removed.html?query=one",
+            "/before.html",
+            "/after.html"
+        ]
+    );
+}
+
 #[tokio::test(flavor = "current_thread")]
 async fn retained_location_rechecks_origin_domain_access() {
     for parent_first in [false, true] {
diff --git a/moli-renderer-v8/tests/fixtures/inactive-location.js b/moli-renderer-v8/tests/fixtures/inactive-location.js
new file mode 100644
index 0000000000..e6a11bfc3c
--- /dev/null
+++ b/moli-renderer-v8/tests/fixtures/inactive-location.js
@@ -0,0 +1,131 @@
+async () => {
+  const result = {checks: 0, failures: []};
+  const check = (name, action, expected) => {
+    let actual;
+    try { actual = action(); } catch (error) { actual = error.name; }
+    result.checks++;
+    if (actual !== expected) result.failures.push({name, actual, expected});
+  };
+  const load = async path => {
+    const frame = document.createElement('iframe');
+    const loaded = new Promise(resolve => frame.onload = resolve);
+    frame.src = path;
+    document.body.append(frame);
+    await loaded;
+    return frame;
+  };
+  const properties = {
+    href: 'about:blank', origin: 'null', protocol: 'about:', host: '',
+    hostname: '', port: '', pathname: 'blank', search: '', hash: ''
+  };
+  const mutations = [
+    ...['href', 'protocol', 'host', 'hostname', 'port', 'pathname', 'search', 'hash']
+      .map(name => [name, (loc, value) => { loc[name] = value; }]),
+    ...['assign', 'replace'].map(name => [name, (loc, value) => loc[name](value)]),
+    ['window-location', (loc, value, win) => { win.location = value; }]
+  ];
+  const detached = (label, win, loc, doc, oldURL) => {
+    check(`${label}:identity`, () => win.location === loc, true);
+    check(`${label}:document-URL`, () => doc.URL, oldURL);
+    for (const [name, expected] of Object.entries(properties)) {
+      check(`${label}:get-${name}`, () => loc[name], expected);
+    }
+    check(`${label}:stringifier`, () => String(loc), 'about:blank');
+    check(`${label}:ancestor-origins`, () => loc.ancestorOrigins.length, 0);
+    const emptyOrigins = loc.ancestorOrigins;
+    check(`${label}:stable-origins`, () => loc.ancestorOrigins === emptyOrigins, true);
+    for (const [name, mutate] of mutations) {
+      check(`${label}:set-${name}`, () => { mutate(loc, 'http://test:test/', win); return 'done'; }, 'done');
+      check(`${label}:after-${name}`, () => loc.href, 'about:blank');
+      let converted = 0;
+      const sentinel = {name: 'ConversionSentinel'};
+      const poison = {toString() { converted++; throw sentinel; }};
+      check(`${label}:conversion-${name}`, () => mutate(loc, poison, win), 'ConversionSentinel');
+      check(`${label}:conversion-count-${name}`, () => converted, 1);
+    }
+    check(`${label}:reload`, () => loc.reload({toString() { throw new Error('not converted'); }}), undefined);
+    for (const name of ['assign', 'replace']) {
+      check(`${label}:required-${name}`, () => loc[name](), 'TypeError');
+    }
+    check(`${label}:unchanged-document-URL`, () => doc.URL, oldURL);
+  };
+  check('live:main-url', () => location.href, document.URL);
+  const blankFrame = document.createElement('iframe');
+  document.body.append(blankFrame);
+  const blankWindow = blankFrame.contentWindow;
+  const blankLocation = blankWindow.location;
+  const blankDocument = blankWindow.document;
+  blankFrame.remove();
+  detached('blank', blankWindow, blankLocation, blankDocument, 'about:blank');
+
+  const frame = await load('/removed.html?query=one#fragment');
+  const win = frame.contentWindow;
+  const loc = win.location;
+  const doc = win.document;
+  const href = loc.href;
+  frame.remove();
+  detached('loaded', win, loc, doc, href);
+  const loadedAgain = new Promise(resolve => frame.onload = resolve);
+  document.body.append(frame);
+  await loadedAgain;
+  check('reinsert:fresh-location', () => frame.contentWindow.location !== loc, true);
+  check('reinsert:old-location', () => loc.href, 'about:blank');
+  check('reinsert:old-navigation', () => { loc.href = 'http://test:test/'; return 'done'; }, 'done');
+  check('reinsert:fresh-url', () => frame.contentWindow.location.href, href);
+  frame.remove();
+
+  for (const [name, mutate] of mutations) {
+    const frame = document.createElement('iframe');
+    document.body.append(frame);
+    const win = frame.contentWindow;
+    const loc = win.location;
+    let converted = 0;
+    const value = {toString() { converted++; frame.remove(); return 'http://test:test/'; }};
+    check(`conversion-removes:${name}`, () => { mutate(loc, value, win); return 'done'; }, 'done');
+    check(`conversion-removes-count:${name}`, () => converted, 1);
+    check(`conversion-removes-url:${name}`, () => loc.href, 'about:blank');
+  }
+
+  const srcdocFrame = document.createElement('iframe');
+  const srcdocLoaded = new Promise(resolve => srcdocFrame.onload = resolve);
+  srcdocFrame.srcdoc = '<!doctype html><p>srcdoc</p>';
+  document.body.append(srcdocFrame);
+  await srcdocLoaded;
+  const srcdocWindow = srcdocFrame.contentWindow;
+  const srcdocLocation = srcdocWindow.location;
+  const srcdocDocument = srcdocWindow.document;
+  const srcdocURL = srcdocDocument.URL;
+  srcdocFrame.remove();
+  detached('srcdoc', srcdocWindow, srcdocLocation, srcdocDocument, srcdocURL);
+
+  const popup = window.open('about:blank');
+  if (!popup) throw new Error('popup should be created');
+  const popupLocation = popup.location;
+  const popupDocument = popup.document;
+  popup.close();
+  // close() queues destruction; yield before probing the retired Location.
+  await new Promise(resolve => setTimeout(resolve, 10));
+  detached('popup', popup, popupLocation, popupDocument, 'about:blank');
+
+  const setter = Object.getOwnPropertyDescriptor(blankLocation, 'href').set;
+  let conversions = 0;
+  const poison = {toString() { conversions++; return 'http://test:test/'; }};
+  for (const receiver of [{}, Object.create(blankLocation), new Proxy(blankLocation, {})]) {
+    check('inactive:invalid-receiver', () => setter.call(receiver, poison), 'TypeError');
+    check('inactive:brand-before-conversion', () => conversions, 0);
+  }
+
+  const navigatedFrame = await load('/before.html');
+  const oldLocation = navigatedFrame.contentWindow.location;
+  const nextLoad = new Promise(resolve => navigatedFrame.onload = resolve);
+  navigatedFrame.src = '/after.html';
+  await nextLoad;
+  check('retired:fresh-location', () => oldLocation !== navigatedFrame.contentWindow.location, true);
+  const activeURL = navigatedFrame.contentWindow.location.href;
+  check('retired:invalid-navigation', () => { oldLocation.assign('http://test:test/'); return 'done'; }, 'done');
+  oldLocation.hash = '#stale';
+  await new Promise(resolve => setTimeout(resolve, 0));
+  check('retired:current-document-unchanged', () => navigatedFrame.contentWindow.location.href, activeURL);
+  navigatedFrame.remove();
+  return result;
+}