diff --git a/temporal-sdk/src/main/java/io/temporal/internal/nexus/NexusTaskHandlerImpl.java b/temporal-sdk/src/main/java/io/temporal/internal/nexus/NexusTaskHandlerImpl.java
index 4d40183c27..c0a538da26 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/nexus/NexusTaskHandlerImpl.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/nexus/NexusTaskHandlerImpl.java
@@ -200,6 +200,9 @@ private void convertKnownFailures(Throwable e) {
       }
       throw new HandlerException(HandlerException.ErrorType.BAD_REQUEST, failure);
     }
+    if (failure instanceof IllegalArgumentException) {
+      throw new HandlerException(HandlerException.ErrorType.BAD_REQUEST, failure);
+    }
     if (failure instanceof ApplicationFailure) {
       if (((ApplicationFailure) failure).isNonRetryable()) {
         throw new HandlerException(
diff --git a/temporal-sdk/src/test/java/io/temporal/internal/nexus/NexusTaskHandlerImplTest.java b/temporal-sdk/src/test/java/io/temporal/internal/nexus/NexusTaskHandlerImplTest.java
index 2ddfa7fda1..5f71fb158e 100644
--- a/temporal-sdk/src/test/java/io/temporal/internal/nexus/NexusTaskHandlerImplTest.java
+++ b/temporal-sdk/src/test/java/io/temporal/internal/nexus/NexusTaskHandlerImplTest.java
@@ -162,6 +162,34 @@ public void startTaskWithUndeserializableInput() throws TimeoutException {
     Assert.assertFalse(e.isRetryable());
   }
 
+  @Test
+  public void startTaskHandlerMissingBothActivityTimeoutOptions() throws TimeoutException {
+    WorkflowClient client = mock(WorkflowClient.class);
+    NexusTaskHandlerImpl nexusTaskHandlerImpl =
+        new NexusTaskHandlerImpl(
+            client, NAMESPACE, TASK_QUEUE, dataConverter, new WorkerInterceptor[] {});
+    nexusTaskHandlerImpl.registerNexusServiceImplementations(
+        new Object[] {new ThrowingIllegalArgumentServiceImpl()});
+    nexusTaskHandlerImpl.start();
+
+    PollNexusTaskQueueResponse.Builder task =
+        PollNexusTaskQueueResponse.newBuilder()
+            .setRequest(
+                Request.newBuilder()
+                    .setStartOperation(
+                        StartOperationRequest.newBuilder()
+                            .setOperation("operation")
+                            .setService("TestNexusService1")
+                            .setPayload(dataConverter.toPayload("input").get())
+                            .build()));
+
+    NexusTaskHandler.Result result =
+        nexusTaskHandlerImpl.handle(new NexusTask(task, null, null), metricsScope);
+    HandlerException e = result.getHandlerException();
+    Assert.assertNotNull(e);
+    Assert.assertEquals(HandlerException.ErrorType.BAD_REQUEST, e.getErrorType());
+  }
+
   @Test
   public void startAsyncSyncOperation() throws TimeoutException {
     WorkflowClient client = mock(WorkflowClient.class);
@@ -405,6 +433,18 @@ public OperationHandler<String, String> operation() {
     }
   }
 
+  @ServiceImpl(service = TestNexusServices.TestNexusService1.class)
+  public class ThrowingIllegalArgumentServiceImpl {
+    @OperationImpl
+    public OperationHandler<String, String> operation() {
+      return OperationHandler.sync(
+          (ctx, details, input) -> {
+            throw new IllegalArgumentException(
+                "at least one of StartToCloseTimeout or ScheduleToCloseTimeout is required");
+          });
+    }
+  }
+
   @ServiceImpl(service = TestNexusServices.TestNexusService1.class)
   public class TestNexusServiceImpl {
     @OperationImpl