diff --git a/types/vuex-i18n/index.d.ts b/types/vuex-i18n/index.d.ts
index d2c5f60b08..8282b99c05 100644
--- a/types/vuex-i18n/index.d.ts
+++ b/types/vuex-i18n/index.d.ts
@@ -32,7 +32,7 @@ export interface Translations {
 
 export interface Ii18n {
   /** get the current locale */
-  locale(): string;
+  locale(): string | null;
 
   /** get all the registered locales */
   locales(): string[];