diff --git a/.changeset/quiet-plums-speak.md b/.changeset/quiet-plums-speak.md
new file mode 100644
index 0000000000..6de20c22db
--- /dev/null
+++ b/.changeset/quiet-plums-speak.md
@@ -0,0 +1,9 @@
+---
+"@workflow/sveltekit": patch
+"@workflow/builders": patch
+"@workflow/errors": patch
+"@workflow/core": patch
+"@workflow/next": patch
+---
+
+Increase flow route limit to max fluid duration and fail run if a single replay exceeds 300s
diff --git a/packages/builders/src/vercel-build-output-api.ts b/packages/builders/src/vercel-build-output-api.ts
index e8dd1768d6..38ecaa2ae9 100644
--- a/packages/builders/src/vercel-build-output-api.ts
+++ b/packages/builders/src/vercel-build-output-api.ts
@@ -110,7 +110,7 @@ export class VercelBuildOutputAPIBuilder extends BaseBuilder {
     // Create package.json and .vc-config.json for workflows function
     await this.createPackageJson(workflowsFuncDir, 'commonjs');
     await this.createVcConfig(workflowsFuncDir, {
-      maxDuration: 60,
+      maxDuration: 'max',
       experimentalTriggers: [WORKFLOW_QUEUE_TRIGGER],
       runtime: this.config.runtime,
     });
diff --git a/packages/core/src/runtime.ts b/packages/core/src/runtime.ts
index da7a407bd3..3ac54ca7d1 100644
--- a/packages/core/src/runtime.ts
+++ b/packages/core/src/runtime.ts
@@ -5,7 +5,10 @@ import {
   WorkflowRuntimeError,
 } from '@workflow/errors';
 import { classifyRunError } from './classify-error.js';
-import { MAX_QUEUE_DELIVERIES } from './runtime/constants.js';
+import {
+  MAX_QUEUE_DELIVERIES,
+  REPLAY_TIMEOUT_MS,
+} from './runtime/constants.js';
 import { parseWorkflowName } from '@workflow/utils/parse-name';
 import {
   type Event,
@@ -161,6 +164,37 @@ export function workflowEntrypoint(
 
       const spanLinks = await linkToCurrentContext();
 
+      // --- Replay timeout guard ---
+      // If the replay takes longer than the timeout, fail the run and exit.
+      // This must be lower than the function's maxDuration (180s) to ensure
+      // the failure is recorded before the platform kills the function.
+      const replayTimeout = setTimeout(async () => {
+        runtimeLogger.error('Workflow replay exceeded timeout', {
+          workflowRunId: runId,
+          timeoutMs: REPLAY_TIMEOUT_MS,
+        });
+        try {
+          const world = getWorld();
+          await world.events.create(
+            runId,
+            {
+              eventType: 'run_failed',
+              specVersion: SPEC_VERSION_CURRENT,
+              eventData: {
+                error: {
+                  message: `Workflow replay exceeded maximum duration (${REPLAY_TIMEOUT_MS / 1000}s)`,
+                },
+                errorCode: RUN_ERROR_CODES.REPLAY_TIMEOUT,
+              },
+            },
+            { requestId }
+          );
+        } catch {
+          // Best effort — process exits regardless
+        }
+        process.exit(1);
+      }, REPLAY_TIMEOUT_MS);
+
       // Invoke user workflow within the propagated trace context and baggage
       return await withTraceContext(traceContext, async () => {
         // Set workflow context as baggage for automatic propagation
@@ -525,6 +559,8 @@ export function workflowEntrypoint(
             ); // End trace
           }
         ); // End withWorkflowBaggage
+      }).finally(() => {
+        clearTimeout(replayTimeout);
       }); // End withTraceContext
     }
   );
diff --git a/packages/core/src/runtime/constants.ts b/packages/core/src/runtime/constants.ts
index 398177d053..b63211c06e 100644
--- a/packages/core/src/runtime/constants.ts
+++ b/packages/core/src/runtime/constants.ts
@@ -11,3 +11,10 @@
 // At 48 attempts the total elapsed time is approximately 20 hours, which is
 // safely under the 24-hour message visibility limit.
 export const MAX_QUEUE_DELIVERIES = 48;
+
+// Maximum time allowed for a single workflow replay execution (in ms).
+// If a replay exceeds this duration, the run is failed and the process exits.
+// This must be lower than the function's maxDuration to ensure the
+// timeout handler has time to post the run_failed event before the platform
+// kills the function.
+export const REPLAY_TIMEOUT_MS = 240_000;
diff --git a/packages/errors/src/error-codes.ts b/packages/errors/src/error-codes.ts
index f83b1baadf..b945303e93 100644
--- a/packages/errors/src/error-codes.ts
+++ b/packages/errors/src/error-codes.ts
@@ -10,6 +10,8 @@ export const RUN_ERROR_CODES = {
   RUNTIME_ERROR: 'RUNTIME_ERROR',
   /** Run exceeded the maximum number of queue deliveries */
   MAX_DELIVERIES_EXCEEDED: 'MAX_DELIVERIES_EXCEEDED',
+  /** Workflow replay exceeded the maximum allowed duration */
+  REPLAY_TIMEOUT: 'REPLAY_TIMEOUT',
 } as const;
 
 export type RunErrorCode =
diff --git a/packages/next/src/builder-deferred.ts b/packages/next/src/builder-deferred.ts
index 86b9eb1bc2..86e1e58c86 100644
--- a/packages/next/src/builder-deferred.ts
+++ b/packages/next/src/builder-deferred.ts
@@ -1109,7 +1109,7 @@ export async function getNextBuilderDeferred() {
           experimentalTriggers: [STEP_QUEUE_TRIGGER],
         },
         workflows: {
-          maxDuration: 60,
+          maxDuration: 'max',
           experimentalTriggers: [WORKFLOW_QUEUE_TRIGGER],
         },
       };
diff --git a/packages/next/src/builder-eager.ts b/packages/next/src/builder-eager.ts
index 11aa2a5c08..c6d6fac0e2 100644
--- a/packages/next/src/builder-eager.ts
+++ b/packages/next/src/builder-eager.ts
@@ -420,7 +420,7 @@ export async function getNextBuilderEager() {
           experimentalTriggers: [STEP_QUEUE_TRIGGER],
         },
         workflows: {
-          maxDuration: 60,
+          maxDuration: 'max',
           experimentalTriggers: [WORKFLOW_QUEUE_TRIGGER],
         },
       };
diff --git a/packages/sveltekit/src/index.ts b/packages/sveltekit/src/index.ts
index 0bb0af3518..3923ecd621 100644
--- a/packages/sveltekit/src/index.ts
+++ b/packages/sveltekit/src/index.ts
@@ -19,7 +19,7 @@ process.on('beforeExit', () => {
     {
       file: '.vercel/output/functions/.well-known/workflow/v1/flow.func/.vc-config.json',
       config: {
-        maxDuration: 60,
+        maxDuration: 'max',
         experimentalTriggers: [
           {
             type: 'queue/v2beta',