diff --git a/tool/build_release.sh b/tool/build_release.sh
index ee87f97f56f..038dc5243fb 100755
--- a/tool/build_release.sh
+++ b/tool/build_release.sh
@@ -62,6 +62,7 @@ flutter pub get
 flutter build web \
   --web-renderer canvaskit \
   --pwa-strategy=offline-first \
+  --dart2js-optimization=O1 \
   --release \
   --no-tree-shake-icons
 
diff --git a/tool/lib/commands/build.dart b/tool/lib/commands/build.dart
index 4ab853ed732..74db2b25a48 100644
--- a/tool/lib/commands/build.dart
+++ b/tool/lib/commands/build.dart
@@ -95,6 +95,8 @@ class BuildCommand extends Command {
             '--web-renderer',
             'canvaskit',
             '--pwa-strategy=offline-first',
+            // Enable default optimizations: https://dart.dev/tools/dart-compile#js
+            '--dart2js-optimization=O1',
             if (buildMode != 'debug') '--$buildMode',
             '--no-tree-shake-icons',
           ],