diff --git a/org.lflang/src/org/lflang/federated/extensions/CExtension.java b/org.lflang/src/org/lflang/federated/extensions/CExtension.java
index 8a69e979c6..a86d6fd1f0 100644
--- a/org.lflang/src/org/lflang/federated/extensions/CExtension.java
+++ b/org.lflang/src/org/lflang/federated/extensions/CExtension.java
@@ -32,7 +32,6 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.LinkedHashMap;
 import java.util.List;
 
 import org.lflang.ASTUtils;
@@ -49,7 +48,6 @@
 import org.lflang.federated.launcher.RtiConfig;
 import org.lflang.federated.serialization.FedROS2CPPSerialization;
 import org.lflang.generator.CodeBuilder;
-import org.lflang.generator.GeneratorUtils;
 import org.lflang.generator.LFGeneratorContext;
 import org.lflang.generator.ReactionInstance;
 import org.lflang.generator.ReactorInstance;
@@ -505,6 +503,7 @@ public String generatePreamble(
             includes.pr("#ifdef __cplusplus\n"
                 + "}\n"
                 + "#endif");
+            includes.pr(generateSerializationIncludes(federate, fileConfig));
         }
 
         return includes.toString();
@@ -537,8 +536,6 @@ protected String makePreamble(
         size_t _lf_action_table_size = %1$s;
         """.formatted(numOfNetworkActions));
 
-        code.pr(generateSerializationPreamble(federate, fileConfig));
-
         code.pr(generateExecutablePreamble(federate, rtiConfig, errorReporter));
 
         code.pr(generateInitializeTriggers(federate, errorReporter));
@@ -551,8 +548,8 @@ protected String makePreamble(
     /**
      * Generate preamble code needed for enabled serializers of the federate.
      */
-    protected String generateSerializationPreamble(FederateInstance federate, FedFileConfig fileConfig) {
-        return CExtensionUtils.generateSerializationPreamble(federate, fileConfig);
+    protected String generateSerializationIncludes(FederateInstance federate, FedFileConfig fileConfig) {
+        return CExtensionUtils.generateSerializationIncludes(federate, fileConfig);
     }
 
     /**
diff --git a/org.lflang/src/org/lflang/federated/extensions/CExtensionUtils.java b/org.lflang/src/org/lflang/federated/extensions/CExtensionUtils.java
index 55a489ce51..7a03655923 100644
--- a/org.lflang/src/org/lflang/federated/extensions/CExtensionUtils.java
+++ b/org.lflang/src/org/lflang/federated/extensions/CExtensionUtils.java
@@ -20,7 +20,6 @@
 import org.lflang.federated.serialization.FedROS2CPPSerialization;
 import org.lflang.federated.serialization.SupportedSerializers;
 import org.lflang.generator.CodeBuilder;
-import org.lflang.generator.GeneratorBase;
 import org.lflang.generator.ReactorInstance;
 import org.lflang.generator.c.CTypes;
 import org.lflang.generator.c.CUtil;
@@ -547,7 +546,7 @@ public static String surroundWithIfFederatedDecentralized(String code) {
     /**
      * Generate preamble code needed for enabled serializers of the federate.
      */
-    public static String generateSerializationPreamble(
+    public static String generateSerializationIncludes(
         FederateInstance federate,
         FedFileConfig fileConfig
     ) {
diff --git a/org.lflang/src/org/lflang/federated/extensions/PythonExtension.java b/org.lflang/src/org/lflang/federated/extensions/PythonExtension.java
index 73bed06f7b..c533a1f765 100644
--- a/org.lflang/src/org/lflang/federated/extensions/PythonExtension.java
+++ b/org.lflang/src/org/lflang/federated/extensions/PythonExtension.java
@@ -57,7 +57,7 @@ public class PythonExtension extends CExtension {
     protected void generateCMakeInclude(FederateInstance federate, FedFileConfig fileConfig) throws IOException {}
 
     @Override
-    protected String generateSerializationPreamble(FederateInstance federate, FedFileConfig fileConfig) {
+    protected String generateSerializationIncludes(FederateInstance federate, FedFileConfig fileConfig) {
         CodeBuilder code = new CodeBuilder();
         for (SupportedSerializers serialization : federate.enabledSerializers) {
             switch (serialization) {