diff --git a/Inc/stm32l4xx_hal_rtc.h b/Inc/stm32l4xx_hal_rtc.h
index 99c1658..428c5ad 100644
--- a/Inc/stm32l4xx_hal_rtc.h
+++ b/Inc/stm32l4xx_hal_rtc.h
@@ -641,6 +641,17 @@
                           } while(0u)
 
 /**
+  * @brief  Check whether if the RTC Calendar is initialized.
+  * @param  __HANDLE__ specifies the RTC handle.
+  * @retval None
+  */
+#if defined(STM32L412xx) || defined(STM32L422xx) || defined (STM32L4P5xx) || defined (STM32L4Q5xx)
+#define __HAL_RTC_IS_CALENDAR_INITIALIZED(__HANDLE__)  ((((RTC->ICSR) & (RTC_ICSR_INITS)) == RTC_ICSR_INITS) ? 1U : 0U)
+#else
+#define __HAL_RTC_IS_CALENDAR_INITIALIZED(__HANDLE__)  (((((__HANDLE__)->Instance->ISR) & (RTC_FLAG_INITS)) == RTC_FLAG_INITS) ? 1U : 0U)
+#endif /* #if defined(STM32L412xx) || defined(STM32L422xx) || defined (STM32L4P5xx) || defined (STM32L4Q5xx) */
+
+/**
   * @brief  Add 1 hour (summer time change).
   * @note   This interface is deprecated.
   *         To manage Daylight Saving Time, please use HAL_RTC_DST_xxx functions
diff --git a/Src/stm32l4xx_hal_rtc.c b/Src/stm32l4xx_hal_rtc.c
index d0c9f1b..666fe93 100644
--- a/Src/stm32l4xx_hal_rtc.c
+++ b/Src/stm32l4xx_hal_rtc.c
@@ -319,32 +319,36 @@
     /* Set RTC state */
     hrtc->State = HAL_RTC_STATE_BUSY;
 
-    /* Disable the write protection for RTC registers */
-    __HAL_RTC_WRITEPROTECTION_DISABLE(hrtc);
-
-    /* Enter Initialization mode */
-    status = RTC_EnterInitMode(hrtc);
-
-    if (status == HAL_OK)
+    /* Check whether the calendar needs to be initialized */
+    if (__HAL_RTC_IS_CALENDAR_INITIALIZED(hrtc) == 0U)
     {
-#if defined(STM32L412xx) || defined(STM32L422xx) || defined (STM32L4P5xx) || defined (STM32L4Q5xx)
-      /* Clear RTC_CR FMT, OSEL, POL and TAMPOE Bits */
-      hrtc->Instance->CR &= ~(RTC_CR_FMT | RTC_CR_POL | RTC_CR_OSEL | RTC_CR_TAMPOE);
-#else
-      /* Clear RTC_CR FMT, OSEL and POL Bits */
-      hrtc->Instance->CR &= ~(RTC_CR_FMT | RTC_CR_OSEL | RTC_CR_POL);
-#endif
-      /* Set RTC_CR register */
-      hrtc->Instance->CR |= (hrtc->Init.HourFormat | hrtc->Init.OutPut | hrtc->Init.OutPutPolarity);
+      /* Disable the write protection for RTC registers */
+      __HAL_RTC_WRITEPROTECTION_DISABLE(hrtc);
 
-      /* Configure the RTC PRER */
-      hrtc->Instance->PRER = (hrtc->Init.SynchPrediv);
-      hrtc->Instance->PRER |= (hrtc->Init.AsynchPrediv << RTC_PRER_PREDIV_A_Pos);
+      /* Enter Initialization mode */
+      status = RTC_EnterInitMode(hrtc);
+
+      if (status == HAL_OK)
+      {
+#if defined(STM32L412xx) || defined(STM32L422xx) || defined (STM32L4P5xx) || defined (STM32L4Q5xx)
+        /* Clear RTC_CR FMT, OSEL, POL and TAMPOE Bits */
+        hrtc->Instance->CR &= ~(RTC_CR_FMT | RTC_CR_POL | RTC_CR_OSEL | RTC_CR_TAMPOE);
+#else
+        /* Clear RTC_CR FMT, OSEL and POL Bits */
+        hrtc->Instance->CR &= ~(RTC_CR_FMT | RTC_CR_OSEL | RTC_CR_POL);
+#endif
+        /* Set RTC_CR register */
+        hrtc->Instance->CR |= (hrtc->Init.HourFormat | hrtc->Init.OutPut | hrtc->Init.OutPutPolarity);
+
+        /* Configure the RTC PRER */
+        hrtc->Instance->PRER = (hrtc->Init.SynchPrediv);
+        hrtc->Instance->PRER |= (hrtc->Init.AsynchPrediv << RTC_PRER_PREDIV_A_Pos);
 
 #if defined (STM32L4P5xx) || defined (STM32L4Q5xx)
-      /* Configure the Binary mode */
-      MODIFY_REG(RTC->ICSR, RTC_ICSR_BIN | RTC_ICSR_BCDU, hrtc->Init.BinMode | hrtc->Init.BinMixBcdU);
+        /* Configure the Binary mode */
+        MODIFY_REG(RTC->ICSR, RTC_ICSR_BIN | RTC_ICSR_BCDU, hrtc->Init.BinMode | hrtc->Init.BinMixBcdU);
 #endif
+      }
 
       /* Exit Initialization mode */
       status = RTC_ExitInitMode(hrtc);
@@ -358,12 +362,20 @@
         hrtc->Instance->OR &= ~(RTC_OR_ALARMOUTTYPE | RTC_OR_OUT_RMP);
         hrtc->Instance->OR |= (hrtc->Init.OutPutType | hrtc->Init.OutPutRemap);
 #endif
-
-        /* Enable the write protection for RTC registers */
-        __HAL_RTC_WRITEPROTECTION_ENABLE(hrtc);
-
-        hrtc->State = HAL_RTC_STATE_READY;
       }
+
+      /* Enable the write protection for RTC registers */
+      __HAL_RTC_WRITEPROTECTION_ENABLE(hrtc);
+    }
+    else
+    {
+      /* The calendar is already initialized */
+      status = HAL_OK;
+    }
+
+    if (status == HAL_OK)
+    {
+        hrtc->State = HAL_RTC_STATE_READY;
     }
   }