diff --git a/packages/pinia/src/createPinia.ts b/packages/pinia/src/createPinia.ts
index f105460e50..796d1c706a 100644
--- a/packages/pinia/src/createPinia.ts
+++ b/packages/pinia/src/createPinia.ts
@@ -18,6 +18,8 @@ export function createPinia(): Pinia {
   let _p: Pinia['_p'] = []
   // plugins added before calling app.use(pinia)
   let toBeInstalled: PiniaPlugin[] = []
+  let afterInitializeCallbacks: ((app: App) => void)[] = []
+  let _a: App | null = null
 
   const pinia: Pinia = markRaw({
     install(app: App) {
@@ -47,9 +49,27 @@ export function createPinia(): Pinia {
     },
 
     _p,
-    // it's actually undefined here
-    // @ts-expect-error
-    _a: null,
+
+    get _a() {
+      return _a!
+    },
+    set _a(app) {
+      _a = app
+
+      if (app) {
+        afterInitializeCallbacks.forEach((cb) => cb(app))
+        afterInitializeCallbacks = []
+      }
+    },
+
+    afterAppInit(cb: (app: App) => void) {
+      if (_a) {
+        cb(_a)
+      } else {
+        afterInitializeCallbacks.push(cb)
+      }
+    },
+
     _e: scope,
     _s: new Map<string, StoreGeneric>(),
     state,
diff --git a/packages/pinia/src/rootStore.ts b/packages/pinia/src/rootStore.ts
index 0509a5c8eb..d5ec8f8fe6 100644
--- a/packages/pinia/src/rootStore.ts
+++ b/packages/pinia/src/rootStore.ts
@@ -57,6 +57,14 @@ export interface Pinia {
    */
   use(plugin: PiniaPlugin): Pinia
 
+  /**
+   * Executes callback after pinia._a is set, or immediately, if it is set already
+   *
+   * @internal
+   * @param cb - callback to execute
+   */
+  afterAppInit(cb: (app: App) => void): void
+
   /**
    * Installed store plugins
    *
diff --git a/packages/pinia/src/store.ts b/packages/pinia/src/store.ts
index d7156a0ea6..1df275aca5 100644
--- a/packages/pinia/src/store.ts
+++ b/packages/pinia/src/store.ts
@@ -676,34 +676,36 @@ function createSetupStore<
   }
 
   // apply all plugins
-  pinia._p.forEach((extender) => {
-    /* istanbul ignore else */
-    if (__DEV__ && IS_CLIENT) {
-      const extensions = scope.run(() =>
-        extender({
-          store,
-          app: pinia._a,
-          pinia,
-          options: optionsForPlugin,
-        })
-      )!
-      Object.keys(extensions || {}).forEach((key) =>
-        store._customProperties.add(key)
-      )
-      assign(store, extensions)
-    } else {
-      assign(
-        store,
-        scope.run(() =>
+  pinia.afterAppInit((app) => {
+    pinia._p.forEach((extender) => {
+      /* istanbul ignore else */
+      if (__DEV__ && IS_CLIENT) {
+        const extensions = scope.run(() =>
           extender({
             store,
-            app: pinia._a,
+            app,
             pinia,
             options: optionsForPlugin,
           })
         )!
-      )
-    }
+        Object.keys(extensions || {}).forEach((key) =>
+          store._customProperties.add(key)
+        )
+        assign(store, extensions)
+      } else {
+        assign(
+          store,
+          scope.run(() =>
+            extender({
+              store,
+              app,
+              pinia,
+              options: optionsForPlugin,
+            })
+          )!
+        )
+      }
+    })
   })
 
   if (