diff --git a/pkgs/cupertino_http/CHANGELOG.md b/pkgs/cupertino_http/CHANGELOG.md
index 16aa082e57..1a254d5317 100644
--- a/pkgs/cupertino_http/CHANGELOG.md
+++ b/pkgs/cupertino_http/CHANGELOG.md
@@ -1,6 +1,9 @@
 ## 1.4.1-wip
 
 * Upgrade to `package:ffigen` 11.0.0.
+* Bring `WebSocket` behavior in line with the documentation by throwing
+  `WebSocketConnectionClosed` rather `StateError` when attempting to send
+  data to or close an already closed `CupertinoWebSocket`.
 * Update minimum supported iOS/macOS versions to be in sync with the minimum
   (best effort) supported for Flutter: iOS 12, macOS 10.14
 
diff --git a/pkgs/cupertino_http/lib/src/cupertino_web_socket.dart b/pkgs/cupertino_http/lib/src/cupertino_web_socket.dart
index c3d50ef508..564c0ba1b1 100644
--- a/pkgs/cupertino_http/lib/src/cupertino_web_socket.dart
+++ b/pkgs/cupertino_http/lib/src/cupertino_web_socket.dart
@@ -106,6 +106,8 @@ class CupertinoWebSocket implements WebSocket {
   /// Handle an incoming message from the peer and schedule receiving the next
   /// message.
   void _handleMessage(URLSessionWebSocketMessage value) {
+    if (_events.isClosed) return;
+
     late WebSocketEvent event;
     switch (value.type) {
       case URLSessionWebSocketMessageType.urlSessionWebSocketMessageTypeString:
@@ -160,7 +162,7 @@ class CupertinoWebSocket implements WebSocket {
   @override
   void sendBytes(Uint8List b) {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
     _task
         .sendMessage(URLSessionWebSocketMessage.fromData(Data.fromList(b)))
@@ -170,7 +172,7 @@ class CupertinoWebSocket implements WebSocket {
   @override
   void sendText(String s) {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
     _task
         .sendMessage(URLSessionWebSocketMessage.fromString(s))
@@ -180,7 +182,7 @@ class CupertinoWebSocket implements WebSocket {
   @override
   Future<void> close([int? code, String? reason]) async {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
 
     if (code != null) {
diff --git a/pkgs/web_socket/CHANGELOG.md b/pkgs/web_socket/CHANGELOG.md
index 55b26d3b7d..2f2a07b25d 100644
--- a/pkgs/web_socket/CHANGELOG.md
+++ b/pkgs/web_socket/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 0.1.3
+
+- Bring the behavior in line with the documentation by throwing
+  `WebSocketConnectionClosed` rather `StateError` when attempting to send
+  data to or close an already closed `WebSocket`.
+
 ## 0.1.2
 
 - Fix a `StateError` in `IOWebSocket` when data is received from the peer
diff --git a/pkgs/web_socket/lib/src/browser_web_socket.dart b/pkgs/web_socket/lib/src/browser_web_socket.dart
index 80135fdc3e..fc66628b7a 100644
--- a/pkgs/web_socket/lib/src/browser_web_socket.dart
+++ b/pkgs/web_socket/lib/src/browser_web_socket.dart
@@ -104,7 +104,7 @@ class BrowserWebSocket implements WebSocket {
   @override
   void sendBytes(Uint8List b) {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
     // Silently discards the data if the connection is closed.
     _webSocket.send(b.jsify()!);
@@ -113,7 +113,7 @@ class BrowserWebSocket implements WebSocket {
   @override
   void sendText(String s) {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
     // Silently discards the data if the connection is closed.
     _webSocket.send(s.jsify()!);
@@ -122,7 +122,7 @@ class BrowserWebSocket implements WebSocket {
   @override
   Future<void> close([int? code, String? reason]) async {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
 
     checkCloseCode(code);
diff --git a/pkgs/web_socket/lib/src/io_web_socket.dart b/pkgs/web_socket/lib/src/io_web_socket.dart
index 8b82218bcf..7ea084bec3 100644
--- a/pkgs/web_socket/lib/src/io_web_socket.dart
+++ b/pkgs/web_socket/lib/src/io_web_socket.dart
@@ -86,7 +86,7 @@ class IOWebSocket implements WebSocket {
   @override
   void sendBytes(Uint8List b) {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
     _webSocket.add(b);
   }
@@ -94,7 +94,7 @@ class IOWebSocket implements WebSocket {
   @override
   void sendText(String s) {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
     _webSocket.add(s);
   }
@@ -102,7 +102,7 @@ class IOWebSocket implements WebSocket {
   @override
   Future<void> close([int? code, String? reason]) async {
     if (_events.isClosed) {
-      throw StateError('WebSocket is closed');
+      throw WebSocketConnectionClosed();
     }
 
     checkCloseCode(code);
diff --git a/pkgs/web_socket/pubspec.yaml b/pkgs/web_socket/pubspec.yaml
index f468dcb379..f9d95a75ff 100644
--- a/pkgs/web_socket/pubspec.yaml
+++ b/pkgs/web_socket/pubspec.yaml
@@ -3,7 +3,7 @@ description: >-
   Any easy-to-use library for communicating with WebSockets
   that has multiple implementations.
 repository: https://github.com/dart-lang/http/tree/master/pkgs/web_socket
-version: 0.1.2
+version: 0.1.3
 
 environment:
   sdk: ^3.3.0
diff --git a/pkgs/web_socket_conformance_tests/lib/src/close_local_tests.dart b/pkgs/web_socket_conformance_tests/lib/src/close_local_tests.dart
index cb496ed776..5cf8e739f8 100644
--- a/pkgs/web_socket_conformance_tests/lib/src/close_local_tests.dart
+++ b/pkgs/web_socket_conformance_tests/lib/src/close_local_tests.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:typed_data';
+
 import 'package:async/async.dart';
 import 'package:stream_channel/stream_channel.dart';
 import 'package:test/test.dart';
@@ -119,13 +121,25 @@ void testCloseLocal(
 
       await expectLater(
           () async => await channel.close(3001, 'Client initiated closure'),
-          throwsStateError);
-      final closeCode = await httpServerQueue.next as int?;
-      final closeReason = await httpServerQueue.next as String?;
+          throwsA(isA<WebSocketConnectionClosed>()));
+    });
 
-      expect(closeCode, 3000);
-      expect(closeReason, 'Client initiated closure');
-      expect(await channel.events.isEmpty, true);
+    test('sendBytes after close', () async {
+      final channel = await channelFactory(uri);
+
+      await channel.close(3000, 'Client initiated closure');
+
+      expect(() => channel.sendBytes(Uint8List(10)),
+          throwsA(isA<WebSocketConnectionClosed>()));
+    });
+
+    test('sendText after close', () async {
+      final channel = await channelFactory(uri);
+
+      await channel.close(3000, 'Client initiated closure');
+
+      expect(() => channel.sendText('Hello World'),
+          throwsA(isA<WebSocketConnectionClosed>()));
     });
   });
 }
diff --git a/pkgs/web_socket_conformance_tests/lib/src/close_remote_tests.dart b/pkgs/web_socket_conformance_tests/lib/src/close_remote_tests.dart
index 647f74e27c..b7b3e5956f 100644
--- a/pkgs/web_socket_conformance_tests/lib/src/close_remote_tests.dart
+++ b/pkgs/web_socket_conformance_tests/lib/src/close_remote_tests.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:typed_data';
+
 import 'package:async/async.dart';
 import 'package:stream_channel/stream_channel.dart';
 import 'package:test/test.dart';
@@ -36,13 +38,24 @@ void testCloseRemote(
           [CloseReceived(4123, 'server closed the connection')]);
     });
 
-    test('send after close received', () async {
+    test('sendBytes after close received', () async {
+      final channel = await channelFactory(uri);
+
+      channel.sendBytes(Uint8List(10));
+      expect(await channel.events.toList(),
+          [CloseReceived(4123, 'server closed the connection')]);
+      expect(() => channel.sendText('test'),
+          throwsA(isA<WebSocketConnectionClosed>()));
+    });
+
+    test('sendText after close received', () async {
       final channel = await channelFactory(uri);
 
       channel.sendText('Please close');
       expect(await channel.events.toList(),
           [CloseReceived(4123, 'server closed the connection')]);
-      expect(() => channel.sendText('test'), throwsStateError);
+      expect(() => channel.sendText('test'),
+          throwsA(isA<WebSocketConnectionClosed>()));
     });
 
     test('close after close received', () async {
@@ -51,7 +64,8 @@ void testCloseRemote(
       channel.sendText('Please close');
       expect(await channel.events.toList(),
           [CloseReceived(4123, 'server closed the connection')]);
-      await expectLater(channel.close, throwsStateError);
+      await expectLater(
+          channel.close, throwsA(isA<WebSocketConnectionClosed>()));
     });
   });
 }