diff --git a/runtime/observatory/BUILD.gn b/runtime/observatory/BUILD.gn
index 360863ccd09..022498ecbae 100644
--- a/runtime/observatory/BUILD.gn
+++ b/runtime/observatory/BUILD.gn
@@ -37,7 +37,6 @@ prebuilt_dart2js_action("build_observatory") {
     "-o",
     rebase_path(output),
     "--packages=" + rebase_path("../../.packages"),
-    "--enable-experiment=non-nullable",
     "--no-sound-null-safety",
   ]
   if (is_debug) {
diff --git a/runtime/observatory/analysis_options.yaml b/runtime/observatory/analysis_options.yaml
index f9cf4b3139c..e579874bf6a 100644
--- a/runtime/observatory/analysis_options.yaml
+++ b/runtime/observatory/analysis_options.yaml
@@ -1,7 +1,4 @@
 analyzer:
-  enable-experiment:
-    - non-nullable
-
   errors:
     dead_code: info
     getter_not_subtype_setter_types: info
diff --git a/runtime/observatory/pubspec.yaml b/runtime/observatory/pubspec.yaml
index ba282ab2f93..ddf5b9c3d96 100644
--- a/runtime/observatory/pubspec.yaml
+++ b/runtime/observatory/pubspec.yaml
@@ -1,6 +1,6 @@
 name: observatory
 environment:
-  sdk: '>=2.10.0 <3.0.0'
+  sdk: '>=2.12.0-0 <3.0.0'
 
 dependencies:
   usage: 'any'