diff --git a/.changeset/fix-fallback-activity-called-on-match.md b/.changeset/fix-fallback-activity-called-on-match.md
new file mode 100644
index 000000000..bd2c4e06b
--- /dev/null
+++ b/.changeset/fix-fallback-activity-called-on-match.md
@@ -0,0 +1,5 @@
+---
+"@stackflow/plugin-history-sync": patch
+---
+
+Fix `fallbackActivity` callback being invoked on every initialization regardless of route matching outcome. Restored the pre-1.8.0 contract: the callback is now called only when no route matches `currentPath`. Apps that perform side effects in this callback (e.g. Sentry logging for unknown deep links) no longer fire on successful matches.
diff --git a/extensions/plugin-history-sync/src/historySyncPlugin.spec.ts b/extensions/plugin-history-sync/src/historySyncPlugin.spec.ts
index 5ba28d372..66a1f6b03 100644
--- a/extensions/plugin-history-sync/src/historySyncPlugin.spec.ts
+++ b/extensions/plugin-history-sync/src/historySyncPlugin.spec.ts
@@ -170,6 +170,55 @@ describe("historySyncPlugin", () => {
     expect(activeActivity(actions.getStack())?.params.title).toEqual("hello");
   });
 
+  test("historySyncPlugin - 초기에 매칭하는 라우트가 있으면 fallbackActivity 콜백을 호출하지 않습니다", async () => {
+    history = createMemoryHistory({
+      initialEntries: ["/articles/123"],
+    });
+
+    const fallbackActivity = jest.fn((): "Home" => "Home");
+
+    stackflow({
+      activityNames: ["Home", "Article"],
+      plugins: [
+        historySyncPlugin({
+          history,
+          routes: {
+            Home: "/home",
+            Article: "/articles/:articleId",
+          },
+          fallbackActivity,
+        }),
+      ],
+    });
+
+    expect(fallbackActivity).not.toHaveBeenCalled();
+  });
+
+  test("historySyncPlugin - 초기에 매칭하는 라우트가 없으면 fallbackActivity 콜백을 plugin instance당 한 번만 호출합니다", async () => {
+    history = createMemoryHistory({
+      initialEntries: ["/non-existent-path"],
+    });
+
+    const fallbackActivity = jest.fn((): "Home" => "Home");
+
+    const plugin = historySyncPlugin({
+      history,
+      routes: {
+        Home: "/home",
+        Article: "/articles/:articleId",
+      },
+      fallbackActivity,
+    });
+
+    const pluginInstance = plugin();
+    pluginInstance.overrideInitialEvents?.({
+      initialEvents: [],
+      initialContext: {},
+    });
+
+    expect(fallbackActivity).toHaveBeenCalledTimes(1);
+  });
+
   test("historySyncPlugin - actions.push() 후에, URL 상태가 알맞게 바뀝니다", async () => {
     await actions.push({
       activityId: "a1",
diff --git a/extensions/plugin-history-sync/src/historySyncPlugin.tsx b/extensions/plugin-history-sync/src/historySyncPlugin.tsx
index 2428d0407..02164e725 100644
--- a/extensions/plugin-history-sync/src/historySyncPlugin.tsx
+++ b/extensions/plugin-history-sync/src/historySyncPlugin.tsx
@@ -228,23 +228,27 @@ export function historySyncPlugin<
         }
 
         const currentPath = resolveCurrentPath();
-        const fallbackActivityName = options.fallbackActivity({
-          initialContext,
+        const matchedActivityRoute = activityRoutes.find((activityRoute) => {
+          const template = makeTemplate(
+            activityRoute,
+            options.urlPatternOptions,
+          );
+          const activityParams = template.parse(currentPath);
+
+          return activityParams !== null;
         });
-        const targetActivityRoute =
-          activityRoutes.find((activityRoute) => {
-            const template = makeTemplate(
-              activityRoute,
-              options.urlPatternOptions,
-            );
-            const activityParams = template.parse(currentPath);
-
-            return activityParams !== null;
-          }) ??
-          activityRoutes.find(
+        const targetActivityRoute = (() => {
+          if (matchedActivityRoute) {
+            return matchedActivityRoute;
+          }
+          const fallbackActivityName = options.fallbackActivity({
+            initialContext,
+          });
+          return activityRoutes.find(
             (activityRoute) =>
               activityRoute.activityName === fallbackActivityName,
           )!;
+        })();
         const pattern = new UrlPattern(
           `${targetActivityRoute.path}(/)`,
           options.urlPatternOptions,