diff --git a/modules/core/system.nix b/modules/core/system.nix
index c8fc8d3..7f26ee4 100644
--- a/modules/core/system.nix
+++ b/modules/core/system.nix
@@ -38,5 +38,9 @@
 
   time.timeZone = "Europe/Amsterdam";
   i18n.defaultLocale = "en_US.UTF-8";
+  i18n.supportedLocales = [
+    "en_US.UTF-8/UTF-8"
+    "ja_JP.UTF-8/UTF-8"
+  ];
   system.stateVersion = "24.05";
 }