diff --git a/components/hal/esp32p4/include/hal/lp_mailbox_ll.h b/components/hal/esp32p4/include/hal/lp_mailbox_ll.h
index b92d308f862..e9eed3f09c9 100644
--- a/components/hal/esp32p4/include/hal/lp_mailbox_ll.h
+++ b/components/hal/esp32p4/include/hal/lp_mailbox_ll.h
@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2025-2026 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -22,6 +22,26 @@
 extern "C" {
 #endif
 
+/**
+ * @brief Enable the mailbox peripheral clock.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ */
+FORCE_INLINE_ATTR void lp_mailbox_ll_enable_clock(lp_mb_dev_t *dev)
+{
+    dev->reg_clk_en.reg_clk_en = 1;
+}
+
+/**
+ * @brief Reset the mailbox peripheral registers.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ */
+FORCE_INLINE_ATTR void lp_mailbox_ll_reset_register(lp_mb_dev_t *dev)
+{
+    (void) dev;
+}
+
 
 /**
  * @brief Get a message (32-bit value) from the LP mailbox.
diff --git a/components/hal/esp32s31/include/hal/lp_mailbox_ll.h b/components/hal/esp32s31/include/hal/lp_mailbox_ll.h
new file mode 100644
index 00000000000..0f51cd1bc44
--- /dev/null
+++ b/components/hal/esp32s31/include/hal/lp_mailbox_ll.h
@@ -0,0 +1,213 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+// The LL layer for ESP32-S31 LP Mailbox register operations
+
+#pragma once
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include "soc/soc.h"
+#include "soc/lp_mailbox_struct.h"
+#include "soc/lp_mailbox_reg.h"
+#include "soc/lp_peri_clkrst_struct.h"
+#include "hal/misc.h"
+#include "esp_attr.h"
+
+#define LP_MAILBOX_LL_MSG_COUNT     16U
+
+typedef mb_dev_t lp_mb_dev_t;
+extern lp_mb_dev_t LP_MAILBOX;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Enable the mailbox peripheral clock.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ */
+FORCE_INLINE_ATTR void lp_mailbox_ll_enable_clock(lp_mb_dev_t *dev)
+{
+    LP_PERI_CLKRST.mailbox.lp_mailbox_clk_en = 1;
+    dev->reg_clk_en.reg_clk_en = 1;
+}
+
+/**
+ * @brief Reset the mailbox peripheral registers.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ */
+FORCE_INLINE_ATTR void lp_mailbox_ll_reset_register(lp_mb_dev_t *dev)
+{
+    LP_PERI_CLKRST.mailbox.lp_mailbox_rst_en = 1;
+    LP_PERI_CLKRST.mailbox.lp_mailbox_rst_en = 0;
+}
+
+/**
+ * @brief Get a message (32-bit value) from the LP mailbox.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param index Index of the message to retrieve (must be less than LP_MAILBOX_LL_MSG_COUNT).
+ *
+ * @return The 32-bit message value at the specified index, or 0 if the index is out of range.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_get_message(lp_mb_dev_t *dev, int index)
+{
+    if (index < LP_MAILBOX_LL_MSG_COUNT) {
+        return (&dev->massege_0.val)[index];
+    }
+    return 0;
+}
+
+/**
+ * @brief Set a message in the LP mailbox.
+ *
+ * @note Writing a message in the mailbox will set the corresponding message's intr_raw bit for
+ * both the LP and HP registers, regardless of the writer!
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param index Index of the message to set (must be less than LP_MAILBOX_LL_MSG_COUNT).
+ * @param val Message (32-bit value) to write to the specified message index.
+ */
+FORCE_INLINE_ATTR void lp_mailbox_ll_set_message(lp_mb_dev_t *dev, int index, uint32_t val)
+{
+    if (index < LP_MAILBOX_LL_MSG_COUNT) {
+        (&dev->massege_0.val)[index] = val;
+    }
+}
+
+/**
+ * @brief Get the raw status of the LP core interrupt register.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ *
+ * @return Raw interrupt status value.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_get_lp_intr_raw(lp_mb_dev_t *dev)
+{
+    return dev->lp_int_raw.val;
+}
+
+/**
+ * @brief Clear LP core interrupt register bits.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param mask Bitmask of interrupts to clear, bit `i` represents message `i`.
+ */
+FORCE_INLINE_ATTR void lp_mailbox_ll_lp_intr_clear(lp_mb_dev_t *dev, uint32_t mask)
+{
+    dev->lp_int_clr.val = mask;
+}
+
+/**
+ * @brief Get the LP core interrupt register status.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ *
+ * @return Interrupt status value.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_lp_intr_status(lp_mb_dev_t *dev)
+{
+    return dev->lp_int_st.val;
+}
+
+/**
+ * @brief Enable mailbox interrupts by mask for the LP core.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param mask Bitmask of interrupts to enable, bit `i` represents message `i`.
+ *
+ * @return Updated interrupt enable register value.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_lp_intr_enable_mask(lp_mb_dev_t *dev, uint32_t mask)
+{
+    dev->lp_int_ena.val |= mask;
+    return dev->lp_int_ena.val;
+}
+
+/**
+ * @brief Disable LP core mailbox interrupts by mask.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param mask Bitmask of interrupts to disable, bit `i` represents message `i`.
+ *
+ * @return Updated interrupt enable register value.
+ */
+
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_lp_intr_disable_mask(lp_mb_dev_t *dev, uint32_t mask)
+{
+    dev->lp_int_ena.val &= ~mask;
+    return dev->lp_int_ena.val;
+}
+
+/**
+ * @brief Get the raw status of the HP core interrupt register.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ *
+ * @return Raw interrupt status value.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_get_hp_intr_raw(lp_mb_dev_t *dev)
+{
+    return dev->hp_int_raw.val;
+}
+
+/**
+ * @brief Clear HP core interrupt register bits.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param mask Bitmask of interrupts to clear, bit `i` represents message `i`.
+ */
+FORCE_INLINE_ATTR void lp_mailbox_ll_hp_intr_clear(lp_mb_dev_t *dev, uint32_t mask)
+{
+    dev->hp_int_clr.val = mask;
+}
+
+/**
+ * @brief Get the HP core interrupt register status.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ *
+ * @return Interrupt status value.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_hp_intr_status(lp_mb_dev_t *dev)
+{
+    return dev->hp_int_st.val;
+}
+
+/**
+ * @brief Enable mailbox interrupts by mask for the HP core.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param mask Bitmask of interrupts to enable, bit `i` represents message `i`.
+ *
+ * @return Updated interrupt enable register value.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_hp_intr_enable_mask(lp_mb_dev_t *dev, uint32_t mask)
+{
+    dev->hp_int_ena.val |= mask;
+    return dev->hp_int_ena.val;
+}
+
+/**
+ * @brief Disable HP core mailbox interrupts by mask.
+ *
+ * @param dev Pointer to the LP mailbox device structure.
+ * @param mask Bitmask of interrupts to disable, bit `i` represents message `i`.
+ *
+ * @return Updated interrupt enable register value.
+ */
+FORCE_INLINE_ATTR uint32_t lp_mailbox_ll_hp_intr_disable_mask(lp_mb_dev_t *dev, uint32_t mask)
+{
+    dev->hp_int_ena.val &= ~mask;
+    return dev->hp_int_ena.val;
+}
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/components/soc/esp32s31/include/soc/Kconfig.soc_caps.in b/components/soc/esp32s31/include/soc/Kconfig.soc_caps.in
index 3ea2ff0aa3c..47973ee3cb2 100644
--- a/components/soc/esp32s31/include/soc/Kconfig.soc_caps.in
+++ b/components/soc/esp32s31/include/soc/Kconfig.soc_caps.in
@@ -1187,6 +1187,10 @@ config SOC_PM_RETENTION_MODULE_NUM
     int
     default 64
 
+config SOC_LP_MAILBOX_SUPPORTED
+    bool
+    default y
+
 config SOC_LP_CORE_SUPPORT_ETM
     bool
     default y
diff --git a/components/soc/esp32s31/include/soc/soc_caps.h b/components/soc/esp32s31/include/soc/soc_caps.h
index 1abda0792cc..904eca6fa1b 100644
--- a/components/soc/esp32s31/include/soc/soc_caps.h
+++ b/components/soc/esp32s31/include/soc/soc_caps.h
@@ -473,7 +473,7 @@
 #define SOC_PM_RETENTION_MODULE_NUM         (64)
 
 /*-------------------------- LP_CORE CAPS ------------------------------------*/
-// #define SOC_LP_MAILBOX_SUPPORTED                 (1) // TODO: [ESP32S31] IDF-14637
+#define SOC_LP_MAILBOX_SUPPORTED                    (1) /*!< LP Core supports LP-mailbox */
 #define SOC_LP_CORE_SUPPORT_ETM                     (1) /*!< LP Core supports ETM wakeup */
 #define SOC_LP_CORE_CONFIGURABLE_BOOT_ADDR          (1) /*!< LP Core has no LP ROM; HP must write the reset_vector address (LP_RAM_BASE+0x80) to LP_SYS.lp_core_boot_addr before triggering LP wake */
 //#define SOC_LP_CORE_SUPPORT_I2C                     (1) /*!< LP Core supports I2C */ TODO IDF-14635
diff --git a/components/ulp/lp_core/lp_core/lp_core_mailbox.c b/components/ulp/lp_core/lp_core/lp_core_mailbox.c
index 3c7458ca467..c19d2894684 100644
--- a/components/ulp/lp_core/lp_core/lp_core_mailbox.c
+++ b/components/ulp/lp_core/lp_core/lp_core_mailbox.c
@@ -158,6 +158,7 @@ esp_err_t lp_core_mailbox_init(lp_mailbox_t *mailbox, lp_mailbox_config_t *confi
         return ESP_ERR_INVALID_STATE;
     }
     hal_memset(&s_mailbox, 0, sizeof(s_mailbox));
+    lp_core_mailbox_impl_init();
     s_mailbox.mb_ctx = lp_core_mailbox_impl_get_context();
     if (s_mailbox.mb_ctx == NULL) {
         return ESP_ERR_INVALID_STATE;
diff --git a/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_hw.c b/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_hw.c
index 7a1b6e8541f..c24765cc0b5 100644
--- a/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_hw.c
+++ b/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_hw.c
@@ -16,6 +16,12 @@
 /* Implementation agnostic interrupt handler */
 static void (*s_intr_handler)(void);
 
+void lp_core_mailbox_impl_init(void)
+{
+    lp_mailbox_ll_enable_clock(&LP_MAILBOX);
+    lp_mailbox_ll_reset_register(&LP_MAILBOX);
+}
+
 void LP_CORE_ISR_ATTR ulp_lp_core_mailbox_intr_handler(void)
 {
     if (s_intr_handler) {
diff --git a/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_sw.c b/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_sw.c
index 9794ef1ea42..cba93407bb7 100644
--- a/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_sw.c
+++ b/components/ulp/lp_core/lp_core/port/lp_core_mailbox_impl_sw.c
@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2025-2026 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -30,6 +30,14 @@ lp_core_mailbox_impl_sw_t g_lp_core_mailbox_impl_sw_ctx;
 /* Implementation agnostic interrupt handler */
 static void (*s_intr_handler)(void);
 
+void lp_core_mailbox_impl_init(void)
+{
+    /* This structure must be initialized by the LP core */
+    memset(&g_lp_core_mailbox_impl_sw_ctx, 0, sizeof(g_lp_core_mailbox_impl_sw_ctx));
+    ulp_lp_core_spinlock_init(&g_lp_core_mailbox_impl_sw_ctx.lock);
+    ulp_lp_core_sw_intr_from_hp_enable(false);
+}
+
 void LP_CORE_ISR_ATTR ulp_lp_core_sw_intr_handler(void)
 {
     if (s_intr_handler) {
@@ -39,10 +47,6 @@ void LP_CORE_ISR_ATTR ulp_lp_core_sw_intr_handler(void)
 
 lp_core_mailbox_ctx_t lp_core_mailbox_impl_get_context(void)
 {
-    /* This structure must be initialized by the LP core */
-    memset(&g_lp_core_mailbox_impl_sw_ctx, 0, sizeof(g_lp_core_mailbox_impl_sw_ctx));
-    ulp_lp_core_spinlock_init(&g_lp_core_mailbox_impl_sw_ctx.lock);
-    ulp_lp_core_sw_intr_from_hp_enable(false);
     return (lp_core_mailbox_ctx_t) &g_lp_core_mailbox_impl_sw_ctx;
 }
 
diff --git a/components/ulp/lp_core/lp_core_mailbox.c b/components/ulp/lp_core/lp_core_mailbox.c
index 1947a2351d5..a7620511399 100644
--- a/components/ulp/lp_core/lp_core_mailbox.c
+++ b/components/ulp/lp_core/lp_core_mailbox.c
@@ -162,6 +162,7 @@ esp_err_t lp_core_mailbox_init(lp_mailbox_t *mailbox, lp_mailbox_config_t *confi
         return ESP_ERR_INVALID_ARG;
     }
 
+    lp_core_mailbox_impl_init();
     lp_core_mailbox_ctx_t context = lp_core_mailbox_impl_get_context();
     if (context == NULL) {
         /* Invalid state! LP core didn't initialize the spinlock? (SW backend) */
diff --git a/components/ulp/lp_core/lp_core_mailbox_impl_hw.c b/components/ulp/lp_core/lp_core_mailbox_impl_hw.c
index 7619a7408ae..0a9b9ab35c5 100644
--- a/components/ulp/lp_core/lp_core_mailbox_impl_hw.c
+++ b/components/ulp/lp_core/lp_core_mailbox_impl_hw.c
@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2025-2026 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -11,6 +11,11 @@
 #include "ulp_lp_core_mailbox_impl_shared.h"
 #include "hal/lp_mailbox_ll.h"
 
+void lp_core_mailbox_impl_init(void)
+{
+    lp_mailbox_ll_enable_clock(&LP_MAILBOX);
+}
+
 /* Mailbox hardware controller, used as a context */
 lp_core_mailbox_ctx_t lp_core_mailbox_impl_get_context(void)
 {
diff --git a/components/ulp/lp_core/lp_core_mailbox_impl_sw.c b/components/ulp/lp_core/lp_core_mailbox_impl_sw.c
index 4bdacbd0f24..ccc1196c871 100644
--- a/components/ulp/lp_core/lp_core_mailbox_impl_sw.c
+++ b/components/ulp/lp_core/lp_core_mailbox_impl_sw.c
@@ -26,6 +26,10 @@ typedef struct {
 /* The structure above is defined by the ULP */
 extern lp_core_mailbox_impl_sw_t ulp_g_lp_core_mailbox_impl_sw_ctx;
 
+void lp_core_mailbox_impl_init(void)
+{
+}
+
 lp_core_mailbox_ctx_t lp_core_mailbox_impl_get_context(void)
 {
     /* Make sure the LP core initialized the spinlock */
diff --git a/components/ulp/lp_core/shared/include/ulp_lp_core_mailbox_impl_shared.h b/components/ulp/lp_core/shared/include/ulp_lp_core_mailbox_impl_shared.h
index d0964d5f9fe..bcc9a5f5487 100644
--- a/components/ulp/lp_core/shared/include/ulp_lp_core_mailbox_impl_shared.h
+++ b/components/ulp/lp_core/shared/include/ulp_lp_core_mailbox_impl_shared.h
@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2025-2026 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -31,6 +31,11 @@ typedef intptr_t lp_message_t;
  */
 typedef void*   lp_core_mailbox_ctx_t;
 
+/**
+ * @brief Initialize the mailbox implementation for the current target/core.
+ */
+void lp_core_mailbox_impl_init(void);
+
 /**
  * @brief Get the mailbox context for the current implementation
  */
diff --git a/docs/doxygen/Doxyfile_esp32s31 b/docs/doxygen/Doxyfile_esp32s31
index f035112c1ed..df2f1528909 100644
--- a/docs/doxygen/Doxyfile_esp32s31
+++ b/docs/doxygen/Doxyfile_esp32s31
@@ -23,5 +23,6 @@ INPUT += \
     $(PROJECT_PATH)/components/ulp/lp_core/lp_core/include/ulp_lp_core_uart.h \
     $(PROJECT_PATH)/components/ulp/lp_core/lp_core/include/ulp_lp_core_utils.h \
     $(PROJECT_PATH)/components/ulp/lp_core/lp_core/include/ulp_lp_core_interrupts.h \
+    $(PROJECT_PATH)/components/ulp/lp_core/lp_core/include/ulp_lp_core_mailbox.h \
     $(PROJECT_PATH)/components/ulp/lp_core/lp_core/include/ulp_lp_core_spi.h \
     $(PROJECT_PATH)/components/ulp/ulp_common/include/ulp_common.h \
diff --git a/examples/system/ulp/.build-test-rules.yml b/examples/system/ulp/.build-test-rules.yml
index d2635ed919f..3ef1abb041d 100644
--- a/examples/system/ulp/.build-test-rules.yml
+++ b/examples/system/ulp/.build-test-rules.yml
@@ -72,9 +72,7 @@ examples/system/ulp/lp_core/lp_i2c:
 
 examples/system/ulp/lp_core/lp_mailbox:
   enable:
-    - if: SOC_LP_CORE_SUPPORTED == 1 and IDF_TARGET not in ["esp32s31"]
-      temporary: true
-      reason: ESP32-S31 not supported yet   # TODO: [ESP32S31] IDF-14637
+    - if: SOC_LP_CORE_SUPPORTED == 1
   <<: *ulp_default_depends
 
 examples/system/ulp/lp_core/lp_spi:
diff --git a/examples/system/ulp/lp_core/lp_mailbox/README.md b/examples/system/ulp/lp_core/lp_mailbox/README.md
index ef550c7b33b..bb51c829846 100644
--- a/examples/system/ulp/lp_core/lp_mailbox/README.md
+++ b/examples/system/ulp/lp_core/lp_mailbox/README.md
@@ -1,5 +1,5 @@
-| Supported Targets | ESP32-C5 | ESP32-C6 | ESP32-P4 |
-| ----------------- | -------- | -------- | -------- |
+| Supported Targets | ESP32-C5 | ESP32-C6 | ESP32-P4 | ESP32-S31 |
+| ----------------- | -------- | -------- | -------- | --------- |
 
 # LP Mailbox Example
 
diff --git a/examples/system/ulp/lp_core/lp_mailbox/pytest_lp_mailbox.py b/examples/system/ulp/lp_core/lp_mailbox/pytest_lp_mailbox.py
index d206a9ddb20..9010bb7522b 100644
--- a/examples/system/ulp/lp_core/lp_mailbox/pytest_lp_mailbox.py
+++ b/examples/system/ulp/lp_core/lp_mailbox/pytest_lp_mailbox.py
@@ -8,9 +8,6 @@ from pytest_embedded_idf.utils import soc_filtered_targets
 
 @pytest.mark.generic
 @idf_parametrize('target', soc_filtered_targets('SOC_LP_CORE_SUPPORTED == 1'), indirect=['target'])
-@pytest.mark.temp_skip_ci(
-    targets=['esp32s31'], reason='s31 bringup on this module is not done, TODO: [ESP32S31] IDF-14637'
-)
 def test_lp_mailbox(dut: Dut) -> None:
     # Wait for LP core to be loaded and running
     dut.expect_exact('LP Mailbox initialized successfully')