diff --git a/soc/arm/st_stm32/stm32l4/CMakeLists.txt b/soc/arm/st_stm32/stm32l4/CMakeLists.txt
index 59be7817eab..8f4b837538d 100644
--- a/soc/arm/st_stm32/stm32l4/CMakeLists.txt
+++ b/soc/arm/st_stm32/stm32l4/CMakeLists.txt
@@ -8,3 +8,5 @@ zephyr_sources(
 zephyr_sources_ifdef(CONFIG_PM
   power.c
   )
+
+zephyr_sources_ifdef(CONFIG_POWEROFF poweroff.c)
diff --git a/soc/arm/st_stm32/stm32l4/Kconfig.series b/soc/arm/st_stm32/stm32l4/Kconfig.series
index 33758aadefd..6ac4f1e704c 100644
--- a/soc/arm/st_stm32/stm32l4/Kconfig.series
+++ b/soc/arm/st_stm32/stm32l4/Kconfig.series
@@ -15,5 +15,6 @@ config SOC_SERIES_STM32L4X
 	select CPU_HAS_ARM_MPU
 	select HAS_SWO
 	select HAS_PM
+	select HAS_POWEROFF
 	help
 	  Enable support for STM32L4 MCU series
diff --git a/soc/arm/st_stm32/stm32l4/power.c b/soc/arm/st_stm32/stm32l4/power.c
index 44fe58e8f49..94b02f5213f 100644
--- a/soc/arm/st_stm32/stm32l4/power.c
+++ b/soc/arm/st_stm32/stm32l4/power.c
@@ -27,19 +27,6 @@ LOG_MODULE_DECLARE(soc, CONFIG_SOC_LOG_LEVEL);
 #define RCC_STOP_WAKEUPCLOCK_SELECTED LL_RCC_STOP_WAKEUPCLOCK_HSI
 #endif
 
-void enter_ultra_low_power_mode(void)
-{
-	/* Configure CPU core */
-	/* Enable CPU deep sleep mode */
-	LL_LPM_EnableDeepSleep();
-	LL_DBGMCU_DisableDBGStandbyMode();
-	/* Enter ultra_low-power mode */
-
-	for (;;) {
-		k_cpu_idle();
-	}
-}
-
 void set_mode_stop(uint8_t substate_id)
 {
 	/* ensure the proper wake-up system clock */
@@ -67,20 +54,6 @@ void set_mode_stop(uint8_t substate_id)
 	}
 }
 
-void set_mode_standby(void)
-{
-	/* Select standby mode */
-	LL_PWR_SetPowerMode(LL_PWR_MODE_STANDBY);
-	enter_ultra_low_power_mode();
-}
-
-void set_mode_shutdown(void)
-{
-	/* Select shutdown mode */
-	LL_PWR_SetPowerMode(LL_PWR_MODE_SHUTDOWN);
-	enter_ultra_low_power_mode();
-}
-
 /* Invoke Low Power/System Off specific Tasks */
 void pm_state_set(enum pm_state state, uint8_t substate_id)
 {
@@ -93,10 +66,10 @@ void pm_state_set(enum pm_state state, uint8_t substate_id)
 		k_cpu_idle();
 		break;
 	case PM_STATE_STANDBY:
-		set_mode_standby();
-		break;
-	case PM_STATE_SOFT_OFF:
-		set_mode_shutdown();
+		LL_PWR_SetPowerMode(LL_PWR_MODE_STANDBY);
+		LL_LPM_EnableDeepSleep();
+		LL_DBGMCU_DisableDBGStandbyMode();
+		k_cpu_idle();
 		break;
 	default:
 		LOG_DBG("Unsupported power state %u", state);
@@ -129,9 +102,6 @@ void pm_state_exit_post_ops(enum pm_state state, uint8_t substate_id)
 		break;
 	case PM_STATE_STANDBY:
 		__fallthrough;
-	case PM_STATE_SOFT_OFF:
-		/* We should not get there */
-		__fallthrough;
 	case PM_STATE_SUSPEND_TO_RAM:
 		__fallthrough;
 	case PM_STATE_SUSPEND_TO_DISK:
diff --git a/soc/arm/st_stm32/stm32l4/poweroff.c b/soc/arm/st_stm32/stm32l4/poweroff.c
new file mode 100644
index 00000000000..b5260dc33cd
--- /dev/null
+++ b/soc/arm/st_stm32/stm32l4/poweroff.c
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/sys/poweroff.h>
+#include <zephyr/toolchain.h>
+
+#include <stm32_ll_cortex.h>
+#include <stm32_ll_pwr.h>
+#include <stm32_ll_system.h>
+
+void z_sys_poweroff(void)
+{
+	LL_PWR_SetPowerMode(LL_PWR_MODE_SHUTDOWN);
+	LL_LPM_EnableDeepSleep();
+	LL_DBGMCU_DisableDBGStandbyMode();
+
+	k_cpu_idle();
+
+	CODE_UNREACHABLE;
+}