diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0e43ad5..67b4b8f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,11 @@
   error with an existing stack trace, instead of creating
   a new stack trace.
 
+#### `dart:indexed_db`
+
+- `IdbFactory.supportsDatabaseNames` has been deprecated. It will always return
+  `false`.
+
 #### `dart:io`
 
 - **Breaking Change** [#47769](https://github.com/dart-lang/sdk/issues/47769):
diff --git a/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart b/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
index e26356c..1df1cc9 100644
--- a/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
+++ b/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
@@ -507,14 +507,10 @@
   }
 
   /**
-   * Checks to see if getDatabaseNames is supported by the current platform.
-   * TODO(terry): Should be able to always return false?
+   * Deprecated. Always returns `false`.
    */
-  bool get supportsDatabaseNames {
-    return supported &&
-        JS('bool', '!!(#.getDatabaseNames || #.webkitGetDatabaseNames)', this,
-            this);
-  }
+  @Deprecated('No longer supported on modern browsers. Always returns false.')
+  bool get supportsDatabaseNames => false;
 
   // To suppress missing implicit constructor warnings.
   factory IdbFactory._() {
diff --git a/tools/dom/templates/html/impl/impl_IDBFactory.darttemplate b/tools/dom/templates/html/impl/impl_IDBFactory.darttemplate
index b046771..112e19a 100644
--- a/tools/dom/templates/html/impl/impl_IDBFactory.darttemplate
+++ b/tools/dom/templates/html/impl/impl_IDBFactory.darttemplate
@@ -63,13 +63,10 @@
   }
 
   /**
-   * Checks to see if getDatabaseNames is supported by the current platform.
-   * TODO(terry): Should be able to always return false?
+   * Deprecated. Always returns `false`.
    */
-  bool get supportsDatabaseNames {
-    return supported && JS('bool',
-        '!!(#.getDatabaseNames || #.webkitGetDatabaseNames)', this, this);
-  }
+  @Deprecated('No longer supported on modern browsers. Always returns false.')
+  bool get supportsDatabaseNames => false;
 
 $!MEMBERS
 }