diff --git a/config/i18n-tasks.yml b/config/i18n-tasks.yml
index c408b9979..5e2a106b5 100644
--- a/config/i18n-tasks.yml
+++ b/config/i18n-tasks.yml
@@ -17,6 +17,7 @@ data:
   read:
     - config/locales/*%{locale}.yml
     - config/locales/**/*%{locale}.yml
+    - config/custom_locales/*%{locale}.yml
 
   # Locale files to write new keys to, based on a list of key pattern => file rules. Matched from top to bottom:
   # `i18n-tasks normalize -p` will force move the keys according to these rules