diff --git a/include/coap3/coap_dgrm_internal.h b/include/coap3/coap_dgrm_internal.h
index 9ee446f2..f5b471c8 100644
--- a/include/coap3/coap_dgrm_internal.h
+++ b/include/coap3/coap_dgrm_internal.h
@@ -126,7 +126,7 @@ void coap_socket_dgrm_close(coap_socket_t *sock);
 /** @} */
 
 #ifdef __cplusplus
-extern "C" {
+}
 #endif
 
 #endif /* COAP_DGRM_INTERNAL_H_ */
diff --git a/include/coap3/coap_subscribe_internal.h b/include/coap3/coap_subscribe_internal.h
index 071956e3..433829bf 100644
--- a/include/coap3/coap_subscribe_internal.h
+++ b/include/coap3/coap_subscribe_internal.h
@@ -309,7 +309,7 @@ int coap_cancel_observe_lkd(coap_session_t *session, coap_binary_t *token,
 /** @} */
 
 #ifdef __cplusplus
-extern "C" {
+}
 #endif
 
 #endif /* COAP_SUBSCRIBE_INTERNAL_H_ */