--- a/mobile/android/moz.configure
+++ b/mobile/android/moz.configure
@@ -32,19 +32,23 @@ project_flag('MOZ_ANDROID_SEARCH_ACTIVIT
 project_flag('MOZ_ANDROID_MLS_STUMBLER',
              help='Include Mozilla Location Service Stumbler on Android',
              default=True)
 
 project_flag('MOZ_ANDROID_DOWNLOAD_CONTENT_SERVICE',
              help='Background service for downloading additional content at runtime',
              default=True)
 
+@depends(milestone, '--help')
+def are_custom_tabs_enabled(milestone):
+    return milestone.is_nightly
+
 project_flag('MOZ_ANDROID_CUSTOM_TABS',
              help='Enable support for Android custom tabs',
-             default=False)
+             default=are_custom_tabs_enabled)
 
 # Enable the Switchboard A/B framework code.
 # Note: The framework is always included in the app. This flag controls
 # usage of the framework.
 project_flag('MOZ_SWITCHBOARD',
              help='Include Switchboard A/B framework on Android',
              default=True)