diff --git a/android_webview/browser/network_service/aw_proxying_restricted_cookie_manager_unittest.cc b/android_webview/browser/network_service/aw_proxying_restricted_cookie_manager_unittest.cc
index 14fa8ef572403..0beaffe47298d 100644
--- a/android_webview/browser/network_service/aw_proxying_restricted_cookie_manager_unittest.cc
+++ b/android_webview/browser/network_service/aw_proxying_restricted_cookie_manager_unittest.cc
@@ -98,6 +98,8 @@ class MockRestrictedCookieManager
       bool force_disable_third_party_cookies,
       GetCookiesStringCallback callback) override {
     last_get_cookies_shared_memory_param_ = get_version_shared_memory;
+    last_get_cookies_site_for_cookies_ = site_for_cookies;
+    last_get_cookies_force_disable_3pcs_ = force_disable_third_party_cookies;
     std::move(callback).Run(network::mojom::kInvalidCookieVersion,
                             base::ReadOnlySharedMemoryRegion(), "");
   }
@@ -116,8 +118,18 @@ class MockRestrictedCookieManager
     return last_get_cookies_shared_memory_param_;
   }
 
+  const net::SiteForCookies& last_get_cookies_site_for_cookies() const {
+    return last_get_cookies_site_for_cookies_;
+  }
+
+  bool last_get_cookies_force_disable_3pcs() const {
+    return last_get_cookies_force_disable_3pcs_;
+  }
+
  private:
   bool last_get_cookies_shared_memory_param_ = false;
+  net::SiteForCookies last_get_cookies_site_for_cookies_;
+  bool last_get_cookies_force_disable_3pcs_ = false;
 };
 
 class AwProxyingRestrictedCookieManagerTest : public testing::Test {
@@ -332,5 +344,73 @@ TEST_F(AwProxyingRestrictedCookieManagerTest,
   EXPECT_FALSE(mock_rcm.last_get_cookies_shared_memory_param());
 }
 
+// Test: The third-party cookie policy is evaluated against the SiteForCookies
+// supplied at bind time, not the per-call value supplied over Mojo.
+TEST_F(AwProxyingRestrictedCookieManagerTest,
+       ThirdPartyPolicyUsesBoundSiteForCookies) {
+  base::test::ScopedFeatureList feature_list;
+  feature_list.InitAndEnableFeature(features::kWebViewLatchedCookiePolicy);
+
+  cookie_access_policy_.SetShouldAcceptCookies(true);
+
+  const GURL kTopLevelUrl("https://top.example/");
+  const GURL kEmbeddedUrl("https://embedded.example/");
+  const net::SiteForCookies kBoundSiteForCookies =
+      net::SiteForCookies::FromUrl(kTopLevelUrl);
+
+  MockRestrictedCookieManager mock_rcm;
+  mojo::Receiver<network::mojom::RestrictedCookieManager> mock_receiver(
+      &mock_rcm);
+
+  mojo::Remote<network::mojom::RestrictedCookieManager> proxy_remote;
+
+  // Bind the proxy with the top-level SiteForCookies. With no associated
+  // frame, the per-WebView third-party setting latches to disabled.
+  CreateProxyOnIOThread(mock_receiver.BindNewPipeAndPassRemote(),
+                        proxy_remote.BindNewPipeAndPassReceiver(),
+                        kBoundSiteForCookies);
+
+  ASSERT_TRUE(
+      base::test::RunUntil([&]() { return proxy_remote.is_connected(); }));
+
+  // Issue a cross-site request whose per-call SiteForCookies claims to be
+  // same-site with the request URL.
+  base::RunLoop get_loop;
+  proxy_remote->GetCookiesString(
+      kEmbeddedUrl, net::SiteForCookies::FromUrl(kEmbeddedUrl),
+      url::Origin::Create(kEmbeddedUrl), net::StorageAccessApiStatus::kNone,
+      /*get_version_shared_memory=*/false,
+      /*is_ad_tagged=*/false,
+      /*apply_devtools_overrides=*/false,
+      /*force_disable_third_party_cookies=*/false,
+      base::BindOnce([](base::RunLoop* run_loop, uint64_t version,
+                        base::ReadOnlySharedMemoryRegion region,
+                        const std::string& str) { run_loop->Quit(); },
+                     &get_loop));
+  get_loop.Run();
+
+  // The proxy must classify the request as third-party using the bound value
+  // and forward that bound value to the underlying RCM.
+  EXPECT_TRUE(mock_rcm.last_get_cookies_force_disable_3pcs());
+  EXPECT_TRUE(mock_rcm.last_get_cookies_site_for_cookies().IsEquivalent(
+      kBoundSiteForCookies));
+
+  // CookiesEnabledFor must likewise report the request as third-party.
+  base::RunLoop enabled_loop;
+  bool enabled_result = true;
+  proxy_remote->CookiesEnabledFor(
+      kEmbeddedUrl, net::SiteForCookies::FromUrl(kEmbeddedUrl),
+      url::Origin::Create(kEmbeddedUrl), net::StorageAccessApiStatus::kNone,
+      /*apply_devtools_overrides=*/false,
+      base::BindOnce(
+          [](base::RunLoop* run_loop, bool* out, bool enabled) {
+            *out = enabled;
+            run_loop->Quit();
+          },
+          &enabled_loop, &enabled_result));
+  enabled_loop.Run();
+  EXPECT_FALSE(enabled_result);
+}
+
 }  // namespace
 }  // namespace android_webview