diff --git a/Sources/GRPCCodeGen/Internal/StructuredSwift+ServiceMetadata.swift b/Sources/GRPCCodeGen/Internal/StructuredSwift+ServiceMetadata.swift
index 8ed3cc88..7b8804fb 100644
--- a/Sources/GRPCCodeGen/Internal/StructuredSwift+ServiceMetadata.swift
+++ b/Sources/GRPCCodeGen/Internal/StructuredSwift+ServiceMetadata.swift
@@ -188,7 +188,7 @@ extension VariableDescription {
 @available(gRPCSwift 2.0, *)
 extension EnumDescription {
   /// ```
-  /// enum <Method> {
+  /// enum <Method>: Sendable {
   ///   typealias Input = <InputType>
   ///   typealias Output = <OutputType>
   ///   static let descriptor = GRPCCore.MethodDescriptor(
@@ -209,6 +209,7 @@ extension EnumDescription {
     return EnumDescription(
       accessModifier: accessModifier,
       name: name,
+      conformances: ["Sendable"],
       members: [
         .commentable(
           .doc("Request type for \"\(literalMethod)\"."),
@@ -235,7 +236,7 @@ extension EnumDescription {
 
   /// ```
   /// enum Method {
-  ///   enum <Method> {
+  ///   enum <Method>: Sendable {
   ///     typealias Input = <MethodInput>
   ///     typealias Output = <MethodOutput>
   ///     static let descriptor = GRPCCore.MethodDescriptor(
@@ -256,7 +257,11 @@ extension EnumDescription {
     methods: [MethodDescriptor],
     namer: Namer = Namer()
   ) -> EnumDescription {
-    var description = EnumDescription(accessModifier: accessModifier, name: "Method")
+    var description = EnumDescription(
+      accessModifier: accessModifier,
+      name: "Method",
+      conformances: ["Sendable"]
+    )
 
     // Add a namespace for each method.
     let methodNamespaces: [Declaration] = methods.map { method in
@@ -294,9 +299,9 @@ extension EnumDescription {
   }
 
   /// ```
-  /// enum <Name> {
+  /// enum <Name>: Sendable {
   ///   static let descriptor = GRPCCore.ServiceDescriptor.<namespacedServicePropertyName>
-  ///   enum Method {
+  ///   enum Method: Sendable {
   ///     ...
   ///   }
   /// }
@@ -308,7 +313,11 @@ extension EnumDescription {
     methods: [MethodDescriptor],
     namer: Namer = Namer()
   ) -> EnumDescription {
-    var description = EnumDescription(accessModifier: accessModifier, name: name)
+    var description = EnumDescription(
+      accessModifier: accessModifier,
+      name: name,
+      conformances: ["Sendable"]
+    )
 
     // static let descriptor = GRPCCore.ServiceDescriptor(fullyQualifiedService: "...")
     let descriptor = VariableDescription.serviceDescriptor(
@@ -344,7 +353,7 @@ extension EnumDescription {
 @available(gRPCSwift 2.0, *)
 extension [CodeBlock] {
   /// ```
-  /// enum <Service> {
+  /// enum <Service>: Sendable {
   ///   ...
   /// }
   ///
diff --git a/Tests/GRPCCodeGenTests/Internal/StructuredSwift+MetadataTests.swift b/Tests/GRPCCodeGenTests/Internal/StructuredSwift+MetadataTests.swift
index 1f297e66..f5636244 100644
--- a/Tests/GRPCCodeGenTests/Internal/StructuredSwift+MetadataTests.swift
+++ b/Tests/GRPCCodeGenTests/Internal/StructuredSwift+MetadataTests.swift
@@ -114,7 +114,7 @@ extension StructuredSwiftTests {
       #expect(render(.variable(decl)) == expected)
     }
 
-    @Test("enum <Method> { ... }", arguments: AccessModifier.allCases)
+    @Test("enum <Method>: Sendable { ... }", arguments: AccessModifier.allCases)
     @available(gRPCSwift 2.0, *)
     func methodNamespaceEnum(access: AccessModifier) {
       let decl: EnumDescription = .methodNamespace(
@@ -127,7 +127,7 @@ extension StructuredSwiftTests {
       )
 
       let expected = """
-        \(access) enum Foo {
+        \(access) enum Foo: Sendable {
           /// Request type for "Foo".
           \(access) typealias Input = FooInput
           /// Response type for "Foo".
@@ -142,7 +142,7 @@ extension StructuredSwiftTests {
       #expect(render(.enum(decl)) == expected)
     }
 
-    @Test("enum Method { ... }", arguments: AccessModifier.allCases)
+    @Test("enum Method: Sendable { ... }", arguments: AccessModifier.allCases)
     @available(gRPCSwift 2.0, *)
     func methodsNamespaceEnum(access: AccessModifier) {
       let decl: EnumDescription = .methodsNamespace(
@@ -161,9 +161,9 @@ extension StructuredSwiftTests {
       )
 
       let expected = """
-        \(access) enum Method {
+        \(access) enum Method: Sendable {
           /// Namespace for "Foo" metadata.
-          \(access) enum Foo {
+          \(access) enum Foo: Sendable {
             /// Request type for "Foo".
             \(access) typealias Input = FooInput
             /// Response type for "Foo".
@@ -183,7 +183,7 @@ extension StructuredSwiftTests {
       #expect(render(.enum(decl)) == expected)
     }
 
-    @Test("enum Method { ... } (no methods)", arguments: AccessModifier.allCases)
+    @Test("enum Method: Sendable { ... } (no methods)", arguments: AccessModifier.allCases)
     @available(gRPCSwift 2.0, *)
     func methodsNamespaceEnumNoMethods(access: AccessModifier) {
       let decl: EnumDescription = .methodsNamespace(
@@ -193,7 +193,7 @@ extension StructuredSwiftTests {
       )
 
       let expected = """
-        \(access) enum Method {
+        \(access) enum Method: Sendable {
           /// Descriptors for all methods in the "bar.Bar" service.
           \(access) static let descriptors: [GRPCCore.MethodDescriptor] = []
         }
@@ -201,7 +201,7 @@ extension StructuredSwiftTests {
       #expect(render(.enum(decl)) == expected)
     }
 
-    @Test("enum <Service> { ... }", arguments: AccessModifier.allCases)
+    @Test("enum <Service>: Sendable { ... }", arguments: AccessModifier.allCases)
     @available(gRPCSwift 2.0, *)
     func serviceNamespaceEnum(access: AccessModifier) {
       let decl: EnumDescription = .serviceNamespace(
@@ -221,13 +221,13 @@ extension StructuredSwiftTests {
       )
 
       let expected = """
-        \(access) enum Foo {
+        \(access) enum Foo: Sendable {
           /// Service descriptor for the "Foo" service.
           \(access) static let descriptor = GRPCCore.ServiceDescriptor(fullyQualifiedService: "Foo")
           /// Namespace for method metadata.
-          \(access) enum Method {
+          \(access) enum Method: Sendable {
             /// Namespace for "Bar" metadata.
-            \(access) enum Bar {
+            \(access) enum Bar: Sendable {
               /// Request type for "Bar".
               \(access) typealias Input = BarInput
               /// Response type for "Bar".
@@ -248,7 +248,7 @@ extension StructuredSwiftTests {
       #expect(render(.enum(decl)) == expected)
     }
 
-    @Test("enum <Service> { ... } (no methods)", arguments: AccessModifier.allCases)
+    @Test("enum <Service>: Sendable { ... } (no methods)", arguments: AccessModifier.allCases)
     @available(gRPCSwift 2.0, *)
     func serviceNamespaceEnumNoMethods(access: AccessModifier) {
       let decl: EnumDescription = .serviceNamespace(
@@ -259,11 +259,11 @@ extension StructuredSwiftTests {
       )
 
       let expected = """
-        \(access) enum Foo {
+        \(access) enum Foo: Sendable {
           /// Service descriptor for the "Foo" service.
           \(access) static let descriptor = GRPCCore.ServiceDescriptor(fullyQualifiedService: "Foo")
           /// Namespace for method metadata.
-          \(access) enum Method {
+          \(access) enum Method: Sendable {
             /// Descriptors for all methods in the "Foo" service.
             \(access) static let descriptors: [GRPCCore.MethodDescriptor] = []
           }
diff --git a/Tests/GRPCCodeGenTests/Internal/Translator/IDLToStructuredSwiftTranslatorSnippetBasedTests.swift b/Tests/GRPCCodeGenTests/Internal/Translator/IDLToStructuredSwiftTranslatorSnippetBasedTests.swift
index 33f4b0d8..4e179aed 100644
--- a/Tests/GRPCCodeGenTests/Internal/Translator/IDLToStructuredSwiftTranslatorSnippetBasedTests.swift
+++ b/Tests/GRPCCodeGenTests/Internal/Translator/IDLToStructuredSwiftTranslatorSnippetBasedTests.swift
@@ -58,11 +58,11 @@ final class IDLToStructuredSwiftTranslatorSnippetBasedTests: XCTestCase {
 
       /// Namespace containing generated types for the "namespaceA.ServiceA" service.
       @available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
-      public enum NamespaceA_ServiceA {
+      public enum NamespaceA_ServiceA: Sendable {
           /// Service descriptor for the "namespaceA.ServiceA" service.
           public static let descriptor = GRPCCore.ServiceDescriptor(fullyQualifiedService: "namespaceA.ServiceA")
           /// Namespace for method metadata.
-          public enum Method {
+          public enum Method: Sendable {
               /// Descriptors for all methods in the "namespaceA.ServiceA" service.
               public static let descriptors: [GRPCCore.MethodDescriptor] = []
           }
diff --git a/Tests/GRPCCodeGenTests/Internal/Translator/TypealiasTranslatorSnippetBasedTests.swift b/Tests/GRPCCodeGenTests/Internal/Translator/TypealiasTranslatorSnippetBasedTests.swift
index 59250a2e..e6db0f3a 100644
--- a/Tests/GRPCCodeGenTests/Internal/Translator/TypealiasTranslatorSnippetBasedTests.swift
+++ b/Tests/GRPCCodeGenTests/Internal/Translator/TypealiasTranslatorSnippetBasedTests.swift
@@ -44,13 +44,13 @@ struct TypealiasTranslatorSnippetBasedTests {
     let expectedSwift = """
       /// Namespace containing generated types for the "namespaceA.ServiceA" service.
       @available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
-      public enum NamespaceA_ServiceA {
+      public enum NamespaceA_ServiceA: Sendable {
           /// Service descriptor for the "namespaceA.ServiceA" service.
           public static let descriptor = GRPCCore.ServiceDescriptor(fullyQualifiedService: "namespaceA.ServiceA")
           /// Namespace for method metadata.
-          public enum Method {
+          public enum Method: Sendable {
               /// Namespace for "MethodA" metadata.
-              public enum MethodA {
+              public enum MethodA: Sendable {
                   /// Request type for "MethodA".
                   public typealias Input = NamespaceA_ServiceARequest
                   /// Response type for "MethodA".