diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.cpp
index c664693edcb..a2ec6637ce6 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.cpp
@@ -36,6 +36,8 @@
 #include "JniJSModulesUnbundle.h"
 #include "NativeArray.h"
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 using namespace facebook::jni;
 
 namespace facebook::react {
@@ -419,3 +421,5 @@ void CatalystInstanceImpl::unregisterFromInspector() {
 }
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.h b/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.h
index a81b3f6c2d0..84bb1179b27 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.h
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/CatalystInstanceImpl.h
@@ -21,6 +21,8 @@
 #include "ModuleRegistryBuilder.h"
 #include "ReactInstanceManagerInspectorTarget.h"
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 namespace facebook::react {
 
 class Instance;
@@ -125,3 +127,5 @@ class CatalystInstanceImpl : public jni::HybridClass<CatalystInstanceImpl> {
 };
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.cpp
index 65a76fc7618..411de2dc5a6 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.cpp
@@ -23,6 +23,8 @@
 #include "CatalystInstanceImpl.h"
 #include "ReadableNativeArray.h"
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 using facebook::xplat::module::CxxModule;
 
 namespace facebook::react {
@@ -152,3 +154,5 @@ jni::local_ref<JReflectMethod::javaobject> JMethodDescriptor::getMethod()
 }
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.h b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.h
index 1e3929a1acf..b10be71da4a 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.h
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.h
@@ -13,6 +13,8 @@
 
 #include "MethodInvoker.h"
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 namespace facebook::react {
 
 class Instance;
@@ -85,3 +87,5 @@ class JavaNativeModule : public NativeModule {
 };
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaScriptExecutorHolder.h b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaScriptExecutorHolder.h
index 55cbc3eb545..682bb7fb2d9 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaScriptExecutorHolder.h
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaScriptExecutorHolder.h
@@ -10,6 +10,8 @@
 #include <cxxreact/JSExecutor.h>
 #include <fbjni/fbjni.h>
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 namespace facebook::react {
 
 class JavaScriptExecutorHolder
@@ -31,3 +33,5 @@ class JavaScriptExecutorHolder
 };
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.cpp
index 35952ac647e..6c07ba28816 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.cpp
@@ -17,6 +17,8 @@
 #include <sstream>
 #include <utility>
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 using magic_number_t = uint32_t;
 const magic_number_t MAGIC_FILE_HEADER = 0xFB0BD1E5;
 const char* MAGIC_FILE_NAME = "UNBUNDLE";
@@ -94,3 +96,5 @@ JSModulesUnbundle::Module JniJSModulesUnbundle::getModule(
 }
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.h b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.h
index 51578df84b7..1a264322905 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.h
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.h
@@ -12,6 +12,8 @@
 #include <android/asset_manager.h>
 #include <cxxreact/JSModulesUnbundle.h>
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 namespace facebook::react {
 
 class JniJSModulesUnbundle : public JSModulesUnbundle {
@@ -41,3 +43,5 @@ class JniJSModulesUnbundle : public JSModulesUnbundle {
 };
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.cpp
index 6eeec15ad65..60bbc204215 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.cpp
@@ -20,6 +20,8 @@
 #include "WritableNativeArray.h"
 #include "WritableNativeMap.h"
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 using namespace facebook::jni;
 
 namespace facebook::react {
@@ -309,3 +311,5 @@ MethodCallResult MethodInvoker::invoke(
 }
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.h b/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.h
index 2c5cfb8bc67..aa801199a6e 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.h
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.h
@@ -13,6 +13,8 @@
 #include <fbjni/fbjni.h>
 #include <folly/dynamic.h>
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 namespace facebook::react {
 
 class Instance;
@@ -62,3 +64,5 @@ class MethodInvoker {
 };
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.cpp
index 71de6e6cf16..77038acb161 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.cpp
@@ -13,6 +13,8 @@
 
 #include <cxxreact/CxxNativeModule.h>
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 namespace facebook::react {
 
 std::string ModuleHolder::getName() const {
@@ -68,3 +70,5 @@ std::vector<std::unique_ptr<NativeModule>> buildNativeModuleList(
 }
 
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.h b/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.h
index ec18985a3fe..c340925682e 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.h
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.h
@@ -14,6 +14,8 @@
 #include "CxxModuleWrapper.h"
 #include "JavaModuleWrapper.h"
 
+#ifndef RCT_FIT_RM_OLD_RUNTIME
+
 namespace facebook::react {
 
 class MessageQueueThread;
@@ -36,3 +38,5 @@ std::vector<std::unique_ptr<NativeModule>> buildNativeModuleList(
         cxxModules,
     std::shared_ptr<MessageQueueThread> moduleMessageQueue);
 } // namespace facebook::react
+
+#endif
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/OnLoad.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/OnLoad.cpp
index 1604b82044a..0533498a685 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/OnLoad.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/OnLoad.cpp
@@ -39,7 +39,9 @@ extern "C" JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved) {
     gloginit::initialize();
     FLAGS_minloglevel = 0;
 #endif
+#ifndef RCT_FIT_RM_OLD_RUNTIME
     CatalystInstanceImpl::registerNatives();
+#endif
     CxxModuleWrapperBase::registerNatives();
     JInspector::registerNatives();
     ReactInstanceManagerInspectorTarget::registerNatives();