diff --git a/drivers/watchdog/wdt_iwdg_stm32.c b/drivers/watchdog/wdt_iwdg_stm32.c
index 50b59476b7e..df3d42d83a7 100644
--- a/drivers/watchdog/wdt_iwdg_stm32.c
+++ b/drivers/watchdog/wdt_iwdg_stm32.c
@@ -84,7 +84,9 @@ static void iwdg_stm32_convert_timeout(uint32_t timeout,
 
 static int iwdg_stm32_setup(const struct device *dev, uint8_t options)
 {
+	struct iwdg_stm32_data *data = IWDG_STM32_DATA(dev);
 	IWDG_TypeDef *iwdg = IWDG_STM32_STRUCT(dev);
+	uint32_t tickstart;
 
 	/* Deactivate running when debugger is attached. */
 	if (options & WDT_OPT_PAUSE_HALTED_BY_DBG) {
@@ -106,8 +108,24 @@ static int iwdg_stm32_setup(const struct device *dev, uint8_t options)
 		return -ENOTSUP;
 	}
 
-	/* Enable the IWDG now (timeout has been installed previoulsy) */
-	LL_IWDG_Enable(iwdg); /* No need to Reload counter */
+	/* Enable the IWDG now and write IWDG registers at the same time */
+	LL_IWDG_Enable(iwdg);
+	LL_IWDG_EnableWriteAccess(iwdg);
+	/* Write the prescaler and reload counter to the IWDG registers*/
+	LL_IWDG_SetPrescaler(iwdg, data->prescaler);
+	LL_IWDG_SetReloadCounter(iwdg, data->reload);
+
+	tickstart = k_uptime_get_32();
+
+	/* Wait for the update operation completed */
+	while (LL_IWDG_IsReady(iwdg) == 0) {
+		if ((k_uptime_get_32() - tickstart) > IWDG_SR_UPDATE_TIMEOUT) {
+			return -ENODEV;
+		}
+	}
+
+	/* Reload counter just before leaving */
+	LL_IWDG_ReloadCounter(iwdg);
 
 	return 0;
 }
@@ -123,16 +141,16 @@ static int iwdg_stm32_disable(const struct device *dev)
 static int iwdg_stm32_install_timeout(const struct device *dev,
 				      const struct wdt_timeout_cfg *config)
 {
-	IWDG_TypeDef *iwdg = IWDG_STM32_STRUCT(dev);
+	struct iwdg_stm32_data *data = IWDG_STM32_DATA(dev);
 	uint32_t timeout = config->window.max * USEC_PER_MSEC;
 	uint32_t prescaler = 0U;
 	uint32_t reload = 0U;
-	uint32_t tickstart;
 
 	if (config->callback != NULL) {
 		return -ENOTSUP;
 	}
 
+	/* Calculating parameters to be applied later, on setup */
 	iwdg_stm32_convert_timeout(timeout, &prescaler, &reload);
 
 	if (!(IS_IWDG_TIMEOUT(timeout) && IS_IWDG_PRESCALER(prescaler) &&
@@ -141,19 +159,11 @@ static int iwdg_stm32_install_timeout(const struct device *dev,
 		return -EINVAL;
 	}
 
-	tickstart = k_uptime_get_32();
-
-	/* Do not enable the wdg during install but during wdt_setup() */
-	LL_IWDG_EnableWriteAccess(iwdg);
-	LL_IWDG_SetPrescaler(iwdg, prescaler);
-
-	/* Wait for the update operation completed */
-	while (LL_IWDG_IsActiveFlag_PVU(iwdg) == 0) {
-		if ((k_uptime_get_32() - tickstart) > IWDG_SR_UPDATE_TIMEOUT) {
-			return -ENODEV;
-		}
-	}
+	/* Store the calculated values to write in the iwdg registers */
+	data->prescaler = prescaler;
+	data->reload = reload;
 
+	/* Do not enable and update the iwdg here but during wdt_setup() */
 	return 0;
 }
 
diff --git a/drivers/watchdog/wdt_iwdg_stm32.h b/drivers/watchdog/wdt_iwdg_stm32.h
index 64e91cfa63c..d953f61b99d 100644
--- a/drivers/watchdog/wdt_iwdg_stm32.h
+++ b/drivers/watchdog/wdt_iwdg_stm32.h
@@ -24,6 +24,8 @@
 struct iwdg_stm32_data {
 	/* IWDG peripheral instance. */
 	IWDG_TypeDef *Instance;
+	uint32_t prescaler;
+	uint32_t reload;
 };
 
 #define IWDG_STM32_DATA(dev)					\