diff --git a/packages/webview_flutter/webview_flutter_web/CHANGELOG.md b/packages/webview_flutter/webview_flutter_web/CHANGELOG.md
index 8ab70f9a78d3..2f40537ebafd 100644
--- a/packages/webview_flutter/webview_flutter_web/CHANGELOG.md
+++ b/packages/webview_flutter/webview_flutter_web/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.1.0+4
+
+* Fixes unreliable encoding of HTML to the iframe element.
+
 ## 0.1.0+3
 
 * Minor fixes for new analysis options.
diff --git a/packages/webview_flutter/webview_flutter_web/lib/webview_flutter_web.dart b/packages/webview_flutter/webview_flutter_web/lib/webview_flutter_web.dart
index 637c24926275..68ed43d9d7a8 100644
--- a/packages/webview_flutter/webview_flutter_web/lib/webview_flutter_web.dart
+++ b/packages/webview_flutter/webview_flutter_web/lib/webview_flutter_web.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:html';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
@@ -183,7 +184,11 @@ class WebWebViewPlatformController implements WebViewPlatformController {
     String? baseUrl,
   }) async {
     // ignore: unsafe_html
-    _element.src = 'data:text/html,${Uri.encodeFull(html)}';
+    _element.src = Uri.dataFromString(
+      html,
+      mimeType: 'text/html',
+      encoding: Encoding.getByName('utf-8'),
+    ).toString();
   }
 
   @override
@@ -199,8 +204,11 @@ class WebWebViewPlatformController implements WebViewPlatformController {
     final String contentType =
         httpReq.getResponseHeader('content-type') ?? 'text/html';
     // ignore: unsafe_html
-    _element.src =
-        'data:$contentType,${Uri.encodeFull(httpReq.responseText ?? '')}';
+    _element.src = Uri.dataFromString(
+      httpReq.responseText ?? '',
+      mimeType: contentType,
+      encoding: Encoding.getByName('utf-8'),
+    ).toString();
   }
 
   @override
diff --git a/packages/webview_flutter/webview_flutter_web/pubspec.yaml b/packages/webview_flutter/webview_flutter_web/pubspec.yaml
index a834c9b77d51..6eff38e96644 100644
--- a/packages/webview_flutter/webview_flutter_web/pubspec.yaml
+++ b/packages/webview_flutter/webview_flutter_web/pubspec.yaml
@@ -2,7 +2,7 @@ name: webview_flutter_web
 description: A Flutter plugin that provides a WebView widget on web.
 repository: https://github.com/flutter/plugins/tree/main/packages/webview_flutter/webview_flutter_web
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 0.1.0+3
+version: 0.1.0+4
 
 environment:
   sdk: ">=2.14.0 <3.0.0"