diff --git a/src/mobx/stores/LocaleOptions.ts b/src/mobx/stores/LocaleOptions.ts
index 9c708d6e..a22d3b3c 100644
--- a/src/mobx/stores/LocaleOptions.ts
+++ b/src/mobx/stores/LocaleOptions.ts
@@ -4,6 +4,7 @@ import { Language, Languages } from "../../context/Locale";
 
 import Persistent from "../interfaces/Persistent";
 import Store from "../interfaces/Store";
+import Syncable from "../interfaces/Syncable";
 
 export interface Data {
     lang: Language;
@@ -51,7 +52,9 @@ export function findLanguage(lang?: string): Language {
 /**
  * Keeps track of user's language settings.
  */
-export default class LocaleOptions implements Store, Persistent<Data> {
+export default class LocaleOptions
+    implements Store, Persistent<Data>, Syncable
+{
     private lang: Language;
 
     /**
@@ -72,6 +75,16 @@ export default class LocaleOptions implements Store, Persistent<Data> {
         };
     }
 
+    apply(_key: "locale", data: unknown, _revision: number): void {
+        this.hydrate(data as Data);
+    }
+
+    @computed toSyncable(): { [key: string]: object } {
+        return {
+            locale: this.toJSON(),
+        };
+    }
+
     @action hydrate(data: Data) {
         this.setLanguage(data.lang);
     }