diff --git a/tests/fuzz/Makefile.am b/tests/fuzz/Makefile.am
index eafd19839..bce0e31a3 100644
--- a/tests/fuzz/Makefile.am
+++ b/tests/fuzz/Makefile.am
@@ -47,7 +47,7 @@ COMMON_LDADD                                              = \
     $(NULL)
 
 COMMON_SOURCES                                            = \
-    fuzzer_platform.c                                       \
+    fuzzer_platform.cpp                                     \
     fuzzer_platform.h                                       \
     $(NULL)
 
diff --git a/tests/fuzz/fuzzer_platform.c b/tests/fuzz/fuzzer_platform.cpp
similarity index 99%
rename from tests/fuzz/fuzzer_platform.c
rename to tests/fuzz/fuzzer_platform.cpp
index af8293aec..5402ee03f 100644
--- a/tests/fuzz/fuzzer_platform.c
+++ b/tests/fuzz/fuzzer_platform.cpp
@@ -28,11 +28,14 @@
 
 #include "openthread-core-config.h"
 
+#include "fuzzer_platform.h"
+
 #include <string.h>
 
 #include <openthread/platform/alarm-micro.h>
 #include <openthread/platform/alarm-milli.h>
 #include <openthread/platform/diag.h>
+#include <openthread/platform/entropy.h>
 #include <openthread/platform/logging.h>
 #include <openthread/platform/misc.h>
 #include <openthread/platform/radio.h>
diff --git a/tests/fuzz/fuzzer_platform.h b/tests/fuzz/fuzzer_platform.h
index 2a87efdc3..343039c38 100644
--- a/tests/fuzz/fuzzer_platform.h
+++ b/tests/fuzz/fuzzer_platform.h
@@ -29,6 +29,8 @@
 #ifndef FUZZER_PLATFORM_H_
 #define FUZZER_PLATFORM_H_
 
+#include <openthread/instance.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif