diff --git a/Examples/ElizaSharedSources/GeneratedSources/eliza.connect.swift b/Examples/ElizaSharedSources/GeneratedSources/eliza.connect.swift
index 46a1893b..ef8cf5e9 100644
--- a/Examples/ElizaSharedSources/GeneratedSources/eliza.connect.swift
+++ b/Examples/ElizaSharedSources/GeneratedSources/eliza.connect.swift
@@ -32,7 +32,7 @@ internal protocol Buf_Connect_Demo_Eliza_V1_ElizaServiceClientInterface {
 }
 
 /// Concrete implementation of `Buf_Connect_Demo_Eliza_V1_ElizaServiceClientInterface`.
-internal final class Buf_Connect_Demo_Eliza_V1_ElizaServiceClient: Buf_Connect_Demo_Eliza_V1_ElizaServiceClientInterface {
+internal final class Buf_Connect_Demo_Eliza_V1_ElizaServiceClient: Buf_Connect_Demo_Eliza_V1_ElizaServiceClientInterface, Sendable {
     private let client: Connect.ProtocolClientInterface
 
     internal init(client: Connect.ProtocolClientInterface) {
diff --git a/Plugins/ConnectSwiftPlugin/ConnectClientGenerator.swift b/Plugins/ConnectSwiftPlugin/ConnectClientGenerator.swift
index d42920e5..e2b8d9f8 100644
--- a/Plugins/ConnectSwiftPlugin/ConnectClientGenerator.swift
+++ b/Plugins/ConnectSwiftPlugin/ConnectClientGenerator.swift
@@ -64,7 +64,9 @@ final class ConnectClientGenerator: Generator {
 
         let className = service.implementationName(using: self.namer)
         self.printLine("/// Concrete implementation of `\(protocolName)`.")
-        self.printLine("\(self.visibility) final class \(className): \(protocolName) {")
+        self.printLine(
+            "\(self.visibility) final class \(className): \(protocolName), Sendable {"
+        )
         self.indent {
             self.printLine("private let client: Connect.ProtocolClientInterface")
             self.printLine()
diff --git a/Tests/ConnectLibraryTests/Generated/grpc/testing/test.connect.swift b/Tests/ConnectLibraryTests/Generated/grpc/testing/test.connect.swift
index 18a6df6a..137c58b7 100644
--- a/Tests/ConnectLibraryTests/Generated/grpc/testing/test.connect.swift
+++ b/Tests/ConnectLibraryTests/Generated/grpc/testing/test.connect.swift
@@ -117,7 +117,7 @@ internal protocol Grpc_Testing_TestServiceClientInterface {
 }
 
 /// Concrete implementation of `Grpc_Testing_TestServiceClientInterface`.
-internal final class Grpc_Testing_TestServiceClient: Grpc_Testing_TestServiceClientInterface {
+internal final class Grpc_Testing_TestServiceClient: Grpc_Testing_TestServiceClientInterface, Sendable {
     private let client: Connect.ProtocolClientInterface
 
     internal init(client: Connect.ProtocolClientInterface) {
@@ -266,7 +266,7 @@ internal protocol Grpc_Testing_UnimplementedServiceClientInterface {
 }
 
 /// Concrete implementation of `Grpc_Testing_UnimplementedServiceClientInterface`.
-internal final class Grpc_Testing_UnimplementedServiceClient: Grpc_Testing_UnimplementedServiceClientInterface {
+internal final class Grpc_Testing_UnimplementedServiceClient: Grpc_Testing_UnimplementedServiceClientInterface, Sendable {
     private let client: Connect.ProtocolClientInterface
 
     internal init(client: Connect.ProtocolClientInterface) {
@@ -317,7 +317,7 @@ internal protocol Grpc_Testing_ReconnectServiceClientInterface {
 }
 
 /// Concrete implementation of `Grpc_Testing_ReconnectServiceClientInterface`.
-internal final class Grpc_Testing_ReconnectServiceClient: Grpc_Testing_ReconnectServiceClientInterface {
+internal final class Grpc_Testing_ReconnectServiceClient: Grpc_Testing_ReconnectServiceClientInterface, Sendable {
     private let client: Connect.ProtocolClientInterface
 
     internal init(client: Connect.ProtocolClientInterface) {
@@ -373,7 +373,7 @@ internal protocol Grpc_Testing_LoadBalancerStatsServiceClientInterface {
 }
 
 /// Concrete implementation of `Grpc_Testing_LoadBalancerStatsServiceClientInterface`.
-internal final class Grpc_Testing_LoadBalancerStatsServiceClient: Grpc_Testing_LoadBalancerStatsServiceClientInterface {
+internal final class Grpc_Testing_LoadBalancerStatsServiceClient: Grpc_Testing_LoadBalancerStatsServiceClientInterface, Sendable {
     private let client: Connect.ProtocolClientInterface
 
     internal init(client: Connect.ProtocolClientInterface) {
@@ -425,7 +425,7 @@ internal protocol Grpc_Testing_XdsUpdateHealthServiceClientInterface {
 }
 
 /// Concrete implementation of `Grpc_Testing_XdsUpdateHealthServiceClientInterface`.
-internal final class Grpc_Testing_XdsUpdateHealthServiceClient: Grpc_Testing_XdsUpdateHealthServiceClientInterface {
+internal final class Grpc_Testing_XdsUpdateHealthServiceClient: Grpc_Testing_XdsUpdateHealthServiceClientInterface, Sendable {
     private let client: Connect.ProtocolClientInterface
 
     internal init(client: Connect.ProtocolClientInterface) {
@@ -473,7 +473,7 @@ internal protocol Grpc_Testing_XdsUpdateClientConfigureServiceClientInterface {
 }
 
 /// Concrete implementation of `Grpc_Testing_XdsUpdateClientConfigureServiceClientInterface`.
-internal final class Grpc_Testing_XdsUpdateClientConfigureServiceClient: Grpc_Testing_XdsUpdateClientConfigureServiceClientInterface {
+internal final class Grpc_Testing_XdsUpdateClientConfigureServiceClient: Grpc_Testing_XdsUpdateClientConfigureServiceClientInterface, Sendable {
     private let client: Connect.ProtocolClientInterface
 
     internal init(client: Connect.ProtocolClientInterface) {