diff --git a/pkgs/test/CHANGELOG.md b/pkgs/test/CHANGELOG.md
index 6ebfe94..d37f60a 100644
--- a/pkgs/test/CHANGELOG.md
+++ b/pkgs/test/CHANGELOG.md
@@ -1,6 +1,8 @@
 ## 1.16.8
 
 * Fix an issue where coverage collection could hang on Chrome. 
+* Disable stack trace chaining by default. It can be re-enabled by explicitly
+  passing the `--chain-stack-traces` flag.
 
 ## 1.16.7
 
diff --git a/pkgs/test/pubspec.yaml b/pkgs/test/pubspec.yaml
index e6663d9..cfa8325 100644
--- a/pkgs/test/pubspec.yaml
+++ b/pkgs/test/pubspec.yaml
@@ -33,7 +33,7 @@
   yaml: ^3.0.0
   # Use an exact version until the test_api and test_core package are stable.
   test_api: 0.3.0
-  test_core: 0.3.18
+  test_core: 0.3.19
 
 dev_dependencies:
   fake_async: ^1.0.0
diff --git a/pkgs/test/test/runner/runner_test.dart b/pkgs/test/test/runner/runner_test.dart
index 2423a15..6100fe6 100644
--- a/pkgs/test/test/runner/runner_test.dart
+++ b/pkgs/test/test/runner/runner_test.dart
@@ -92,7 +92,6 @@
                                       especially for asynchronous code. It may be useful to disable
                                       to provide improved test performance but at the cost of
                                       debuggability.
-                                      (defaults to on)
     --no-retry                        Don't rerun tests that have retry set.
     --test-randomize-ordering-seed    Use the specified seed to randomize the execution order of test cases.
                                       Must be a 32bit unsigned integer or "random".
@@ -389,25 +388,25 @@
   });
 
   group('runs failing tests', () {
-    test('defaults to chaining stack traces', () async {
+    test('respects the chain-stack-traces flag', () async {
       await d.file('test.dart', _asyncFailure).create();
 
-      var test = await runTest(['test.dart']);
+      var test = await runTest(['test.dart', '--chain-stack-traces']);
       expect(test.stdout, emitsThrough(contains('asynchronous gap')));
       await test.shouldExit(1);
     });
 
-    test('respects the chain-stack-traces flag', () async {
+    test('defaults to not chaining stack traces', () async {
       await d.file('test.dart', _asyncFailure).create();
 
-      var test = await runTest(['test.dart', '--no-chain-stack-traces']);
+      var test = await runTest(['test.dart']);
       expect(
           test.stdout,
           containsInOrder([
             '00:00 +0: failure',
             '00:00 +0 -1: failure [E]',
             'oh no',
-            'test.dart 8:7  main.<fn>',
+            'test.dart 8:7   main.<fn>.<fn>',
           ]));
       await test.shouldExit(1);
     });
diff --git a/pkgs/test_core/CHANGELOG.md b/pkgs/test_core/CHANGELOG.md
index 0be6431..b05631c 100644
--- a/pkgs/test_core/CHANGELOG.md
+++ b/pkgs/test_core/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.3.19
+
+* Disable stack trace chaining by default.
+
 ## 0.3.18
 
 * Update `spawnHybridCode` to default to the current packages language version.
diff --git a/pkgs/test_core/lib/src/runner/configuration/args.dart b/pkgs/test_core/lib/src/runner/configuration/args.dart
index 253924b..afb064b 100644
--- a/pkgs/test_core/lib/src/runner/configuration/args.dart
+++ b/pkgs/test_core/lib/src/runner/configuration/args.dart
@@ -102,7 +102,7 @@
           'especially for asynchronous code. It may be useful to disable\n'
           'to provide improved test performance but at the cost of\n'
           'debuggability.',
-      defaultsTo: true);
+      defaultsTo: false);
   parser.addFlag('no-retry',
       help: "Don't rerun tests that have retry set.",
       defaultsTo: false,
diff --git a/pkgs/test_core/pubspec.yaml b/pkgs/test_core/pubspec.yaml
index 5f3f06b..b30dc5e 100644
--- a/pkgs/test_core/pubspec.yaml
+++ b/pkgs/test_core/pubspec.yaml
@@ -1,5 +1,5 @@
 name: test_core
-version: 0.3.18
+version: 0.3.19
 description: A basic library for writing tests and running them on the VM.
 homepage: https://github.com/dart-lang/test/blob/master/pkgs/test_core