diff --git a/Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+SwiftThunkPrinting.swift b/Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+SwiftThunkPrinting.swift
index 913f4c0d..9d20bf6f 100644
--- a/Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+SwiftThunkPrinting.swift
+++ b/Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+SwiftThunkPrinting.swift
@@ -836,13 +836,15 @@ extension JNISwift2JavaGenerator {
   }
 
   private func printHeader(_ printer: inout CodePrinter) {
+    // `public import` so the thunk file remains valid under
+    // `InternalImportsByDefault` (SE-0409)
     printer.print(
       """
       // Generated by swift-java
 
-      import SwiftJava
-      import SwiftJavaJNICore
-      import SwiftJavaRuntimeSupport
+      public import SwiftJava
+      public import SwiftJavaJNICore
+      public import SwiftJavaRuntimeSupport
 
       """
     )