diff --git a/wire-runtime-swift/build.gradle.kts b/wire-runtime-swift/build.gradle.kts
index cc01ee614c..1f2f221271 100644
--- a/wire-runtime-swift/build.gradle.kts
+++ b/wire-runtime-swift/build.gradle.kts
@@ -7,7 +7,7 @@ plugins {
 }
 
 library {
-  sourceCompatibility = SwiftVersion.SWIFT5
+  sourceCompatibility = SwiftVersion.SWIFT6
   module.set("Wire")
 }
 
diff --git a/wire-tests-proto3-swift/build.gradle.kts b/wire-tests-proto3-swift/build.gradle.kts
index 33b9829eb3..cdc3bfaa86 100644
--- a/wire-tests-proto3-swift/build.gradle.kts
+++ b/wire-tests-proto3-swift/build.gradle.kts
@@ -5,7 +5,7 @@ plugins {
 }
 
 library {
-  sourceCompatibility = SwiftVersion.SWIFT5
+  sourceCompatibility = SwiftVersion.SWIFT6
   dependencies {
     api(projects.wireRuntimeSwift)
   }
diff --git a/wire-tests-swift/manifest/module_one/build.gradle.kts b/wire-tests-swift/manifest/module_one/build.gradle.kts
index 4eaca885e3..78fd5cfd75 100644
--- a/wire-tests-swift/manifest/module_one/build.gradle.kts
+++ b/wire-tests-swift/manifest/module_one/build.gradle.kts
@@ -5,7 +5,7 @@ plugins {
 }
 
 library {
-  sourceCompatibility = SwiftVersion.SWIFT5
+  sourceCompatibility = SwiftVersion.SWIFT6
   dependencies {
     api(projects.wireRuntimeSwift)
     implementation(projects.wireTestsSwift.manifest.moduleAddress)
diff --git a/wire-tests-swift/manifest/module_three/build.gradle.kts b/wire-tests-swift/manifest/module_three/build.gradle.kts
index 9f0a6a64a2..621fa38084 100644
--- a/wire-tests-swift/manifest/module_three/build.gradle.kts
+++ b/wire-tests-swift/manifest/module_three/build.gradle.kts
@@ -5,7 +5,7 @@ plugins {
 }
 
 library {
-  sourceCompatibility = SwiftVersion.SWIFT5
+  sourceCompatibility = SwiftVersion.SWIFT6
   dependencies {
     api(projects.wireRuntimeSwift)
     implementation(projects.wireTestsSwift.manifest.moduleOne)
diff --git a/wire-tests-swift/manifest/module_two/build.gradle.kts b/wire-tests-swift/manifest/module_two/build.gradle.kts
index 63291756b9..92846fb619 100644
--- a/wire-tests-swift/manifest/module_two/build.gradle.kts
+++ b/wire-tests-swift/manifest/module_two/build.gradle.kts
@@ -5,7 +5,7 @@ plugins {
 }
 
 library {
-  sourceCompatibility = SwiftVersion.SWIFT5
+  sourceCompatibility = SwiftVersion.SWIFT6
   dependencies {
     api(projects.wireRuntimeSwift)
     implementation(projects.wireTestsSwift.manifest.moduleOne)
diff --git a/wire-tests-swift/no-manifest/build.gradle.kts b/wire-tests-swift/no-manifest/build.gradle.kts
index 0fba03312e..4e616b41cd 100644
--- a/wire-tests-swift/no-manifest/build.gradle.kts
+++ b/wire-tests-swift/no-manifest/build.gradle.kts
@@ -5,7 +5,7 @@ plugins {
 }
 
 library {
-  sourceCompatibility = SwiftVersion.SWIFT5
+  sourceCompatibility = SwiftVersion.SWIFT6
   dependencies {
     api(projects.wireRuntimeSwift)
   }