diff --git a/arch/sim/src/sim/up_rptun.c b/arch/sim/src/sim/up_rptun.c
index 57c3ff52249..3d57570743a 100644
--- a/arch/sim/src/sim/up_rptun.c
+++ b/arch/sim/src/sim/up_rptun.c
@@ -237,6 +237,12 @@ int up_rptun_init(void)
   syslog_rpmsg_server_init();
 #endif
 
+#if CONFIG_SIM_RPTUN_MASTER
+  rpmsg_rtc_server_initialize();
+#else
+  up_rtc_set_lowerhalf(rpmsg_rtc_initialize("server", 0));
+#endif
+
 #ifdef CONFIG_FS_HOSTFS_RPMSG
   hostfs_rpmsg_init("server");
 #endif
diff --git a/boards/sim/sim/sim/configs/rpproxy/defconfig b/boards/sim/sim/sim/configs/rpproxy/defconfig
index d678dbe0a66..0e4f71c7ba1 100644
--- a/boards/sim/sim/sim/configs/rpproxy/defconfig
+++ b/boards/sim/sim/sim/configs/rpproxy/defconfig
@@ -52,6 +52,11 @@ CONFIG_READLINE_CMD_HISTORY=y
 CONFIG_READLINE_TABCOMPLETION=y
 CONFIG_RPMSG_UART=y
 CONFIG_RPTUN=y
+CONFIG_RTC=y
+CONFIG_RTC_ARCH=y
+CONFIG_RTC_DRIVER=y
+CONFIG_RTC_EXTERNAL=y
+CONFIG_RTC_RPMSG=y
 CONFIG_SCHED_CHILD_STATUS=y
 CONFIG_SCHED_HAVE_PARENT=y
 CONFIG_SCHED_HPWORK=y
diff --git a/boards/sim/sim/sim/configs/rpserver/defconfig b/boards/sim/sim/sim/configs/rpserver/defconfig
index ef66d275ce5..e319f757895 100644
--- a/boards/sim/sim/sim/configs/rpserver/defconfig
+++ b/boards/sim/sim/sim/configs/rpserver/defconfig
@@ -62,6 +62,10 @@ CONFIG_READLINE_CMD_HISTORY=y
 CONFIG_READLINE_TABCOMPLETION=y
 CONFIG_RPMSG_UART=y
 CONFIG_RPTUN=y
+CONFIG_RTC=y
+CONFIG_RTC_ARCH=y
+CONFIG_RTC_DRIVER=y
+CONFIG_RTC_RPMSG=y
 CONFIG_SCHED_CHILD_STATUS=y
 CONFIG_SCHED_HAVE_PARENT=y
 CONFIG_SCHED_HPWORK=y