diff --git a/js/components/src/components/chat/chat-box.tsx b/js/components/src/components/chat/chat-box.tsx
index de3a27440..71ff8cfd4 100644
--- a/js/components/src/components/chat/chat-box.tsx
+++ b/js/components/src/components/chat/chat-box.tsx
@@ -694,14 +694,20 @@ export function ChatBox({
               }}
               onPress={() => {
                 const did = linfo?.author?.did ?? profile?.did;
-                if (did) {
-                  const u = new URL(window.location.href);
-                  u.pathname = `/chat-popout/${did}`;
-                  window.open(
-                    u.toString(),
-                    "_blank",
-                    "popup=true,width=480,height=600",
-                  );
+                if (!did) return;
+                const u = new URL(window.location.href);
+                u.pathname = `/chat-popout/${did}`;
+                const popup = window.open(
+                  u.toString(),
+                  "_blank",
+                  "popup=true,width=480,height=600",
+                );
+                if (!popup) {
+                  // A blocked popup returns null. Don't hide the panel and
+                  // leave the viewer with no chat at all — send this tab to
+                  // the popout instead.
+                  window.location.assign(u.toString());
+                  return;
                 }
                 setIsChatVisible?.(false);
               }}
diff --git a/js/e2e-web/flows/07-chat-popout.spec.ts b/js/e2e-web/flows/07-chat-popout.spec.ts
index 42822cd90..704b1a780 100644
--- a/js/e2e-web/flows/07-chat-popout.spec.ts
+++ b/js/e2e-web/flows/07-chat-popout.spec.ts
@@ -47,3 +47,29 @@ test("07-chat-popout: opens one window, leaves the stream page alone", async ({
   await popup.close();
   expect(page.context().pages()).toHaveLength(1);
 });
+
+test("07-chat-popout: blocked popup falls back to this tab", async ({
+  page,
+}) => {
+  await loginThroughPds(page);
+
+  await page.goto(`${HTTPS_URL}/`);
+  await page.getByTestId("home-stream-card").first().click();
+  await expect(
+    page.getByText("Now streaming - e2e test stream").first(),
+  ).toBeVisible({ timeout: 30_000 });
+  const popoutButton = page.getByTestId("chat-popout-button");
+  await expect(popoutButton).toBeVisible({ timeout: 30_000 });
+
+  let popups = 0;
+  page.on("popup", () => popups++);
+  // A popup blocker makes window.open return null with no window; the button
+  // must not just hide the chat panel and leave the viewer with nothing.
+  await page.evaluate(() => {
+    window.open = () => null;
+  });
+
+  await popoutButton.click();
+  await page.waitForURL(/\/chat-popout\/did:plc:/, { timeout: 10_000 });
+  expect(popups).toBe(0);
+});