diff --git a/packages/trigger-sdk/src/v3/ai-shared.ts b/packages/trigger-sdk/src/v3/ai-shared.ts
index d0434e24672..bf0409660f4 100644
--- a/packages/trigger-sdk/src/v3/ai-shared.ts
+++ b/packages/trigger-sdk/src/v3/ai-shared.ts
@@ -278,3 +278,30 @@ export function waitBeforeEofResubscribe(attempt: number, signal: AbortSignal):
     if (signal.aborted) done();
   });
 }
+
+/**
+ * Combine multiple `AbortSignal` instances into a single signal, falling back
+ * to manual listener forwarding on runtimes without `AbortSignal.any` (such as
+ * Safari / iOS Safari < 17.4).
+ */
+export function anyAbortSignal(signals: AbortSignal[]): AbortSignal {
+  if (typeof AbortSignal.any === "function") {
+    return AbortSignal.any(signals);
+  }
+
+  const controller = new AbortController();
+  const aborted = signals.find((s) => s.aborted);
+  if (aborted) {
+    controller.abort(aborted.reason);
+    return controller.signal;
+  }
+
+  for (const s of signals) {
+    s.addEventListener("abort", () => controller.abort(s.reason), {
+      once: true,
+      signal: controller.signal,
+    });
+  }
+  return controller.signal;
+}
+
diff --git a/packages/trigger-sdk/src/v3/chat-client.ts b/packages/trigger-sdk/src/v3/chat-client.ts
index 1a421af4990..0f765f57d53 100644
--- a/packages/trigger-sdk/src/v3/chat-client.ts
+++ b/packages/trigger-sdk/src/v3/chat-client.ts
@@ -31,6 +31,7 @@ import {
 } from "@trigger.dev/core/v3";
 import type { ChatInputChunk, ChatTaskWirePayload } from "./ai-shared.js";
 import {
+  anyAbortSignal,
   chatRunTags,
   MAX_EOF_RESUBSCRIBES,
   slimSubmitMessageForWire,
@@ -815,7 +816,7 @@ export class AgentChat<TAgent = unknown> {
 
     const internalAbort = new AbortController();
     const combinedSignal = abortSignal
-      ? AbortSignal.any([abortSignal, internalAbort.signal])
+      ? anyAbortSignal([abortSignal, internalAbort.signal])
       : internalAbort.signal;
 
     // Detached once the stream ends (see the `finally` below): a caller reusing
diff --git a/packages/trigger-sdk/src/v3/chat.test.ts b/packages/trigger-sdk/src/v3/chat.test.ts
index a4d8b9841fa..fab2633f92b 100644
--- a/packages/trigger-sdk/src/v3/chat.test.ts
+++ b/packages/trigger-sdk/src/v3/chat.test.ts
@@ -2950,4 +2950,74 @@ describe("TriggerChatTransport", () => {
       expect(textChunks).toHaveLength(2);
     });
   });
+
+  describe("Safari < 17.4 compatibility (no AbortSignal.any)", () => {
+    it("streams and propagates caller aborts when AbortSignal.any is undefined", async () => {
+      const originalAny = AbortSignal.any;
+      Object.defineProperty(AbortSignal, "any", {
+        value: undefined,
+        configurable: true,
+        writable: true,
+      });
+
+      try {
+        global.fetch = vi.fn().mockImplementation(async (url: string | URL) => {
+          const urlStr = typeof url === "string" ? url : url.toString();
+          if (isSessionStreamAppendUrl(urlStr)) return defaultAppendResponse();
+          if (isSessionOutSubscribeUrl(urlStr)) {
+            return defaultSseResponse([
+              { type: "text-delta", id: "p1", delta: "Safari fallback" },
+              { type: "trigger:turn-complete" },
+            ]);
+          }
+          throw new Error(`Unexpected URL: ${urlStr}`);
+        });
+
+        const transport = new TriggerChatTransport({
+          task: "my-chat-task",
+          accessToken: () => "pat",
+          sessions: {
+            "chat-safari": { publicAccessToken: "p", isStreaming: true },
+          },
+        });
+
+        const callerAbort = new AbortController();
+        const stream = await transport.sendMessages({
+          trigger: "submit-message",
+          chatId: "chat-safari",
+          messageId: undefined,
+          messages: [createUserMessage("Hi from Safari 16")],
+          abortSignal: callerAbort.signal,
+        });
+        const chunks = await drainChunks(stream);
+        expect(chunks).toEqual([{ type: "text-delta", id: "p1", delta: "Safari fallback" }]);
+
+        const preAborted = new AbortController();
+        preAborted.abort(new Error("user stopped"));
+        let receivedAbortOnSubscribe = false;
+        global.fetch = vi.fn().mockImplementation(async (url: string | URL, init?: RequestInit) => {
+          const urlStr = typeof url === "string" ? url : url.toString();
+          if (isSessionOutSubscribeUrl(urlStr)) {
+            receivedAbortOnSubscribe = Boolean(init?.signal?.aborted);
+            return defaultSseResponse([{ type: "trigger:turn-complete" }]);
+          }
+          throw new Error(`Unexpected URL: ${urlStr}`);
+        });
+
+        const resumed = await transport.reconnectToStream({
+          chatId: "chat-safari",
+          abortSignal: preAborted.signal,
+        });
+        await drainChunks(resumed!);
+        expect(receivedAbortOnSubscribe).toBe(true);
+      } finally {
+        Object.defineProperty(AbortSignal, "any", {
+          value: originalAny,
+          configurable: true,
+          writable: true,
+        });
+      }
+    });
+  });
 });
+
diff --git a/packages/trigger-sdk/src/v3/chat.ts b/packages/trigger-sdk/src/v3/chat.ts
index ba74aff2cc2..ec6ba027a91 100644
--- a/packages/trigger-sdk/src/v3/chat.ts
+++ b/packages/trigger-sdk/src/v3/chat.ts
@@ -46,6 +46,7 @@ function byteLength(body: string): number {
 }
 import { ChatTabCoordinator } from "./chat-tab-coordinator.js";
 import {
+  anyAbortSignal,
   MAX_EOF_RESUBSCRIBES,
   slimSubmitMessageForWire,
   waitBeforeEofResubscribe,
@@ -1355,7 +1356,7 @@ export class TriggerChatTransport implements ChatTransport<UIMessage> {
     this.activeStreams.set(options.chatId, abortController);
 
     const abortSignal = options.abortSignal
-      ? AbortSignal.any([options.abortSignal, abortController.signal])
+      ? anyAbortSignal([options.abortSignal, abortController.signal])
       : abortController.signal;
 
     return this.subscribeToSessionStream(state, abortSignal, options.chatId, {
@@ -2064,7 +2065,7 @@ export class TriggerChatTransport implements ChatTransport<UIMessage> {
     let didSettle = false;
     this.activeStreams.set(chatId, internalAbort);
     const combinedSignal = abortSignal
-      ? AbortSignal.any([abortSignal, internalAbort.signal])
+      ? anyAbortSignal([abortSignal, internalAbort.signal])
       : internalAbort.signal;
 
     if (abortSignal) {