diff --git a/psalm-baseline.xml b/psalm-baseline.xml
index 73bbf9d6..365428c8 100644
--- a/psalm-baseline.xml
+++ b/psalm-baseline.xml
@@ -109,12 +109,23 @@
       <code><![CDATA[$workflowType]]></code>
     </PropertyNotSetInConstructor>
   </file>
+  <file src="src/Client/Schedule/ScheduleOptions.php">
+    <DeprecatedProperty>
+      <code><![CDATA[$this->namespace]]></code>
+    </DeprecatedProperty>
+  </file>
   <file src="src/Client/Schedule/Spec/ScheduleSpec.php">
     <DeprecatedProperty>
       <code><![CDATA[$this->excludeCalendarList]]></code>
       <code><![CDATA[$this->excludeCalendarList]]></code>
     </DeprecatedProperty>
   </file>
+  <file src="src/Client/ScheduleClient.php">
+    <DeprecatedProperty>
+      <code><![CDATA[$options->namespace]]></code>
+      <code><![CDATA[$options->namespace]]></code>
+    </DeprecatedProperty>
+  </file>
   <file src="src/Client/Update/UpdateHandle.php">
     <PossiblyNullArgument>
       <code><![CDATA[$result->getSuccess()]]></code>
diff --git a/src/Client/Schedule/ScheduleOptions.php b/src/Client/Schedule/ScheduleOptions.php
index ffdbb0d2..247b8a9f 100644
--- a/src/Client/Schedule/ScheduleOptions.php
+++ b/src/Client/Schedule/ScheduleOptions.php
@@ -16,20 +16,23 @@ final class ScheduleOptions
 {
     use CloneWith;
 
-    public readonly string $namespace;
-    public readonly bool $triggerImmediately;
+    /**
+     * @deprecated will be removed in the next major version.
+     */
+    public readonly ?string $namespace;
 
     /**
      * @var list<BackfillPeriod>
      */
     public readonly array $backfills;
 
+    public readonly bool $triggerImmediately;
     public readonly EncodedCollection $memo;
     public readonly EncodedCollection $searchAttributes;
 
     private function __construct()
     {
-        $this->namespace = 'default';
+        $this->namespace = null;
         $this->triggerImmediately = false;
         $this->backfills = [];
         $this->memo = EncodedCollection::empty();
@@ -41,6 +44,10 @@ public static function new(): self
         return new self();
     }
 
+    /**
+     * @deprecated Configure the namespace on the {@see \Temporal\Client\ClientOptions} instead
+     *             when creating the {@see \Temporal\Client\ScheduleClient}.
+     */
     public function withNamespace(string $namespace): self
     {
         /** @see self::$namespace */
diff --git a/src/Client/ScheduleClient.php b/src/Client/ScheduleClient.php
index aebeb5a3..94c2a9d1 100644
--- a/src/Client/ScheduleClient.php
+++ b/src/Client/ScheduleClient.php
@@ -81,7 +81,7 @@ public function createSchedule(
         $request = new CreateScheduleRequest();
         $request
             ->setRequestId(Uuid::v4())
-            ->setNamespace($options->namespace)
+            ->setNamespace($options->namespace ?? $this->clientOptions->namespace)
             ->setScheduleId($scheduleId)
             ->setIdentity($this->clientOptions->identity);
 
@@ -123,7 +123,7 @@ public function createSchedule(
             $this->converter,
             $this->marshaller,
             $this->protoConverter,
-            $options->namespace,
+            $options->namespace ?? $this->clientOptions->namespace,
             $scheduleId,
         );
     }
diff --git a/tests/Unit/Schedule/ScheduleClientTestCase.php b/tests/Unit/Schedule/ScheduleClientTestCase.php
index 66cfbd55..af692a6b 100644
--- a/tests/Unit/Schedule/ScheduleClientTestCase.php
+++ b/tests/Unit/Schedule/ScheduleClientTestCase.php
@@ -17,6 +17,7 @@
 use Temporal\Client\Schedule\Policy\ScheduleOverlapPolicy;
 use Temporal\Client\Schedule\Policy\SchedulePolicies;
 use Temporal\Client\Schedule\Schedule;
+use Temporal\Client\Schedule\ScheduleOptions;
 use Temporal\Client\Schedule\Spec\CalendarSpec;
 use Temporal\Client\Schedule\Spec\Range;
 use Temporal\Client\Schedule\Spec\ScheduleSpec;
@@ -63,6 +64,59 @@ public function testCreateSchedule(): void
         );
     }
 
+    public function testCreateScheduleNamespaceFromOptions(): void
+    {
+        $testContext = new class {
+            public CreateScheduleRequest $request;
+        };
+        // Prepare mocks
+        $clientMock = $this->createMock(ServiceClientInterface::class);
+        $clientMock->expects($this->once())
+            ->method('CreateSchedule')
+            ->with($this->callback(fn(CreateScheduleRequest $request) => $testContext->request = $request or true))
+            ->willReturn((new CreateScheduleResponse())->setConflictToken('test-conflict-token'));
+        $scheduleClient = $this->createScheduleClient(
+            client: $clientMock,
+        );
+        $scheduleDto = $this->getScheduleDto();
+
+        $scheduleClient->createSchedule(
+            $scheduleDto,
+            options: ScheduleOptions::new()->withNamespace('test-namespace'),
+            scheduleId: 'test-id',
+        );
+
+        $this->assertTrue(isset($testContext->request));
+        $this->assertSame('test-namespace', $testContext->request->getNamespace());
+    }
+
+    public function testCreateScheduleNamespaceFromServiceClient(): void
+    {
+        $testContext = new class {
+            public CreateScheduleRequest $request;
+        };
+        // Prepare mocks
+        $clientMock = $this->createMock(ServiceClientInterface::class);
+        $clientMock->expects($this->once())
+            ->method('CreateSchedule')
+            ->with($this->callback(fn(CreateScheduleRequest $request) => $testContext->request = $request or true))
+            ->willReturn((new CreateScheduleResponse())->setConflictToken('test-conflict-token'));
+        $scheduleClient = $this->createScheduleClient(
+            client: $clientMock,
+            clientOptions: (new ClientOptions())->withNamespace('test-namespace'),
+        );
+        $scheduleDto = $this->getScheduleDto();
+
+        $scheduleClient->createSchedule(
+            $scheduleDto,
+            options: ScheduleOptions::new(),
+            scheduleId: 'test-id',
+        );
+
+        $this->assertTrue(isset($testContext->request));
+        $this->assertSame('test-namespace', $testContext->request->getNamespace());
+    }
+
     public function testCreateScheduleWithoutWorkflowId(): void
     {
         $testContext = new class {
diff --git a/tests/Unit/Schedule/ScheduleOptionsTestCase.php b/tests/Unit/Schedule/ScheduleOptionsTestCase.php
index 923e75f6..cbb59e11 100644
--- a/tests/Unit/Schedule/ScheduleOptionsTestCase.php
+++ b/tests/Unit/Schedule/ScheduleOptionsTestCase.php
@@ -22,7 +22,7 @@ public function testWithNamespace(): void
         $new = $init->withNamespace('foo');
 
         $this->assertNotSame($init, $new, 'immutable method clones object');
-        $this->assertSame('default', $init->namespace, 'default value was not changed');
+        $this->assertNull($init->namespace, 'default value was not changed');
         $this->assertSame('foo', $new->namespace);
     }