diff --git a/apps/web/src/components/HistorySwipeNavigation.browser.test.tsx b/apps/web/src/components/HistorySwipeNavigation.browser.test.tsx
index b2e6fcaaaf402..3cad5371e9bc9 100644
--- a/apps/web/src/components/HistorySwipeNavigation.browser.test.tsx
+++ b/apps/web/src/components/HistorySwipeNavigation.browser.test.tsx
@@ -27,17 +27,19 @@ describe("HistorySwipeNavigation", () => {
     ["swiping back at a shadow-root scroller's left edge navigates", "shadow", 0, -130, true],
     ["swiping back over a panel without overflow navigates", "none", 0, -130, true],
     ["a swipe that started in a closed dialog keeps the thread", "closed-dialog", 0, -130, false],
+    ["swiping back over an open alert dialog keeps the thread", "alertdialog", 0, -130, false],
   ] as const)("%s", async (_name, scroller, scrollLeft, deltaX, navigates) => {
     navigateHistory.mockReset();
     await using screen = await render(<HistorySwipeNavigation />);
     const panel = screen.container.appendChild(document.createElement("div"));
     const root = scroller.startsWith("shadow") ? panel.attachShadow({ mode: "open" }) : panel;
     const viewport = root.appendChild(document.createElement("div"));
-    const noOverflow = scroller === "none" || scroller === "closed-dialog";
+    const noOverflow = scroller === "none" || scroller.endsWith("dialog");
     viewport.style.cssText = `width: 200px; overflow-x: ${noOverflow ? "visible" : "auto"}`;
     const content = viewport.appendChild(document.createElement("div"));
     content.style.cssText = `height: 20px; width: ${noOverflow ? 100 : 1000}px`;
     viewport.scrollLeft = scrollLeft;
+    if (scroller === "alertdialog") panel.setAttribute("role", "alertdialog");
 
     if (scroller === "closed-dialog") {
       panel.setAttribute("role", "dialog");
diff --git a/apps/web/src/components/HistorySwipeNavigation.tsx b/apps/web/src/components/HistorySwipeNavigation.tsx
index 767b4285c696f..88de2402d36e0 100644
--- a/apps/web/src/components/HistorySwipeNavigation.tsx
+++ b/apps/web/src/components/HistorySwipeNavigation.tsx
@@ -57,7 +57,11 @@ function lockSwipeAxis(
 ): Exclude<SwipeGesture, { kind: "pending" }> {
   const { path, sumX, sumY } = pending;
   if (Math.abs(sumX) <= Math.abs(sumY)) return { kind: "ignored" };
-  if (path.some((node) => node instanceof Element && node.matches('[role="dialog"]'))) {
+  if (
+    path.some(
+      (node) => node instanceof Element && node.matches('[role="dialog"], [role="alertdialog"]'),
+    )
+  ) {
     return { kind: "ignored" };
   }
   if (canScrollHorizontally(path, sumX)) return { kind: "ignored" };