diff --git a/test/Grpc.IntegrationTests/GrpcDurableTaskClientIntegrationTests.cs b/test/Grpc.IntegrationTests/GrpcDurableTaskClientIntegrationTests.cs
index e64865a9..18892f1a 100644
--- a/test/Grpc.IntegrationTests/GrpcDurableTaskClientIntegrationTests.cs
+++ b/test/Grpc.IntegrationTests/GrpcDurableTaskClientIntegrationTests.cs
@@ -16,6 +16,8 @@ namespace Microsoft.DurableTask.Grpc.Tests;
 public class DurableTaskGrpcClientIntegrationTests : IntegrationTestBase
 {
     const string OrchestrationName = "TestOrchestration";
+    const int PollingTimeoutSeconds = 5;
+    const int PollingIntervalMilliseconds = 100;
 
     public DurableTaskGrpcClientIntegrationTests(ITestOutputHelper output, GrpcSidecarFixture sidecarFixture)
         : base(output, sidecarFixture)
@@ -291,26 +293,6 @@ await restartAction.Should().ThrowAsync<ArgumentException>()
             .WithMessage("*An orchestration with the instanceId non-existent-instance-id was not found*");
     }
 
-    Task<HostTestLifetime> StartAsync()
-    {
-        static async Task<string> Orchestration(TaskOrchestrationContext context, bool shouldThrow)
-        {
-            context.SetCustomStatus("waiting");
-            await context.WaitForExternalEvent<string>("event");
-            if (shouldThrow)
-            {
-                throw new InvalidOperationException("Orchestration failed");
-            }
-
-            return $"{shouldThrow} -> output";
-        }
-
-        return this.StartWorkerAsync(b =>
-        {
-            b.AddTasks(tasks => tasks.AddOrchestratorFunc<bool, string>(OrchestrationName, Orchestration));
-        });
-    }
-
     [Fact]
     public async Task ScheduleNewOrchestrationInstance_WithDedupeStatuses_ThrowsWhenInstanceExists()
     {
@@ -482,6 +464,223 @@ await createAction.Should().ThrowAsync<RpcException>()
             .Where(e => e.StatusCode == StatusCode.AlreadyExists);
     }
 
+    [Fact]
+    public async Task SuspendAndResumeInstance_EndToEnd()
+    {
+        // Arrange
+        await using HostTestLifetime server = await this.StartLongRunningAsync();
+
+        string instanceId = await server.Client.ScheduleNewOrchestrationInstanceAsync(
+            OrchestrationName, input: false);
+
+        // Wait for the orchestration to start
+        await server.Client.WaitForInstanceStartAsync(instanceId, default);
+
+        // Act - Suspend the orchestration
+        await server.Client.SuspendInstanceAsync(instanceId, "Test suspension", default);
+
+        // Poll for suspended status
+        OrchestrationMetadata? suspendedMetadata = await this.PollForStatusAsync(
+            server.Client, instanceId, OrchestrationRuntimeStatus.Suspended, default);
+
+        // Assert - Verify orchestration is suspended
+        suspendedMetadata.Should().NotBeNull();
+        suspendedMetadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Suspended);
+        suspendedMetadata.InstanceId.Should().Be(instanceId);
+
+        // Act - Resume the orchestration
+        await server.Client.ResumeInstanceAsync(instanceId, "Test resumption", default);
+
+        // Poll for running status
+        OrchestrationMetadata? resumedMetadata = await this.PollForStatusAsync(
+            server.Client, instanceId, OrchestrationRuntimeStatus.Running, default);
+
+        // Assert - Verify orchestration is running again
+        resumedMetadata.Should().NotBeNull();
+        resumedMetadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Running);
+
+        // Complete the orchestration
+        await server.Client.RaiseEventAsync(instanceId, "event", default);
+        await server.Client.WaitForInstanceCompletionAsync(instanceId, default);
+
+        // Verify the orchestration completed successfully
+        OrchestrationMetadata? completedMetadata = await server.Client.GetInstanceAsync(instanceId, false);
+        completedMetadata.Should().NotBeNull();
+        completedMetadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Completed);
+    }
+
+    [Fact]
+    public async Task SuspendInstance_WithoutReason_Succeeds()
+    {
+        // Arrange
+        await using HostTestLifetime server = await this.StartLongRunningAsync();
+
+        string instanceId = await server.Client.ScheduleNewOrchestrationInstanceAsync(
+            OrchestrationName, input: false);
+
+        await server.Client.WaitForInstanceStartAsync(instanceId, default);
+
+        // Act - Suspend without a reason
+        await server.Client.SuspendInstanceAsync(instanceId, cancellation: default);
+
+        // Poll for suspended status
+        OrchestrationMetadata? suspendedMetadata = await this.PollForStatusAsync(
+            server.Client, instanceId, OrchestrationRuntimeStatus.Suspended, default);
+
+        // Assert
+        suspendedMetadata.Should().NotBeNull();
+        suspendedMetadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Suspended);
+    }
+
+    [Fact]
+    public async Task ResumeInstance_WithoutReason_Succeeds()
+    {
+        // Arrange
+        await using HostTestLifetime server = await this.StartLongRunningAsync();
+
+        string instanceId = await server.Client.ScheduleNewOrchestrationInstanceAsync(
+            OrchestrationName, input: false);
+
+        await server.Client.WaitForInstanceStartAsync(instanceId, default);
+        await server.Client.SuspendInstanceAsync(instanceId, "Test suspension", default);
+
+        // Wait for suspension
+        await this.PollForStatusAsync(server.Client, instanceId, OrchestrationRuntimeStatus.Suspended, default);
+
+        // Act - Resume without a reason
+        await server.Client.ResumeInstanceAsync(instanceId, cancellation: default);
+
+        // Poll for running status
+        OrchestrationMetadata? resumedMetadata = await this.PollForStatusAsync(
+            server.Client, instanceId, OrchestrationRuntimeStatus.Running, default);
+
+        // Assert
+        resumedMetadata.Should().NotBeNull();
+        resumedMetadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Running);
+    }
+
+    [Fact]
+    public async Task SuspendInstance_AlreadyCompleted_NoError()
+    {
+        // Arrange
+        await using HostTestLifetime server = await this.StartAsync();
+
+        string instanceId = await server.Client.ScheduleNewOrchestrationInstanceAsync(
+            OrchestrationName, input: false);
+
+        await server.Client.WaitForInstanceStartAsync(instanceId, default);
+        await server.Client.RaiseEventAsync(instanceId, "event", default);
+        await server.Client.WaitForInstanceCompletionAsync(instanceId, default);
+
+        // Verify it's completed
+        OrchestrationMetadata? completedMetadata = await server.Client.GetInstanceAsync(instanceId, false);
+        completedMetadata.Should().NotBeNull();
+        completedMetadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Completed);
+
+        // Act - Try to suspend a completed orchestration (should not throw)
+        await server.Client.SuspendInstanceAsync(instanceId, "Test suspension", default);
+
+        // Assert - Status should remain completed
+        OrchestrationMetadata? metadata = await server.Client.GetInstanceAsync(instanceId, false);
+        metadata.Should().NotBeNull();
+        metadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Completed);
+    }
+
+    [Fact]
+    public async Task ResumeInstance_NotSuspended_NoError()
+    {
+        // Arrange
+        await using HostTestLifetime server = await this.StartLongRunningAsync();
+
+        string instanceId = await server.Client.ScheduleNewOrchestrationInstanceAsync(
+            OrchestrationName, input: false);
+
+        await server.Client.WaitForInstanceStartAsync(instanceId, default);
+
+        // Verify it's running
+        OrchestrationMetadata? runningMetadata = await server.Client.GetInstanceAsync(instanceId, false);
+        runningMetadata.Should().NotBeNull();
+        runningMetadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Running);
+
+        // Act - Try to resume an already running orchestration (should not throw)
+        await server.Client.ResumeInstanceAsync(instanceId, "Test resumption", default);
+
+        // Assert - Status should remain running
+        OrchestrationMetadata? metadata = await server.Client.GetInstanceAsync(instanceId, false);
+        metadata.Should().NotBeNull();
+        metadata!.RuntimeStatus.Should().Be(OrchestrationRuntimeStatus.Running);
+    }
+
+    Task<HostTestLifetime> StartAsync()
+    {
+        static async Task<string> Orchestration(TaskOrchestrationContext context, bool shouldThrow)
+        {
+            context.SetCustomStatus("waiting");
+            await context.WaitForExternalEvent<string>("event");
+            if (shouldThrow)
+            {
+                throw new InvalidOperationException("Orchestration failed");
+            }
+
+            return $"{shouldThrow} -> output";
+        }
+
+        return this.StartWorkerAsync(b =>
+        {
+            b.AddTasks(tasks => tasks.AddOrchestratorFunc<bool, string>(OrchestrationName, Orchestration));
+        });
+    }
+
+    Task<HostTestLifetime> StartLongRunningAsync()
+    {
+        static async Task<string> LongRunningOrchestration(TaskOrchestrationContext context, bool shouldThrow)
+        {
+            context.SetCustomStatus("waiting");
+            // Wait for external event or a timer (30 seconds) to allow suspend/resume operations
+            Task<string> eventTask = context.WaitForExternalEvent<string>("event");
+            Task timerTask = context.CreateTimer(TimeSpan.FromSeconds(30), CancellationToken.None);
+            Task completedTask = await Task.WhenAny(eventTask, timerTask);
+
+            if (completedTask == timerTask)
+            {
+                throw new TimeoutException("Timed out waiting for external event 'event'.");
+            }
+            
+            if (shouldThrow)
+            {
+                throw new InvalidOperationException("Orchestration failed");
+            }
+
+            return $"{shouldThrow} -> output";
+        }
+
+        return this.StartWorkerAsync(b =>
+        {
+            b.AddTasks(tasks => tasks.AddOrchestratorFunc<bool, string>(OrchestrationName, LongRunningOrchestration));
+        });
+    }
+
+    async Task<OrchestrationMetadata?> PollForStatusAsync(
+        DurableTaskClient client,
+        string instanceId,
+        OrchestrationRuntimeStatus expectedStatus,
+        CancellationToken cancellation = default)
+    {
+        DateTime deadline = DateTime.UtcNow.AddSeconds(PollingTimeoutSeconds);
+        while (DateTime.UtcNow < deadline)
+        {
+            OrchestrationMetadata? metadata = await client.GetInstanceAsync(instanceId, false, cancellation);
+            if (metadata?.RuntimeStatus == expectedStatus)
+            {
+                return metadata;
+            }
+
+            await Task.Delay(TimeSpan.FromMilliseconds(PollingIntervalMilliseconds), cancellation);
+        }
+
+        return await client.GetInstanceAsync(instanceId, false, cancellation);
+    }
+
     class DateTimeToleranceComparer : IEqualityComparer<DateTimeOffset>
     {
         public bool Equals(DateTimeOffset x, DateTimeOffset y) => (x - y).Duration() < TimeSpan.FromMilliseconds(100);