diff --git a/src/boards/xiao_nrf52840_ble_s340/board.h b/src/boards/xiao_nrf52840_ble_s340/board.h
new file mode 100644
index 00000000..eb977349
--- /dev/null
+++ b/src/boards/xiao_nrf52840_ble_s340/board.h
@@ -0,0 +1,68 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Ha Thach for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef _XIAO_BLE_S340
+#define _XIAO_BLE_S340
+
+#define _PINNUM(port, pin)    ((port)*32 + (pin))
+
+/*------------------------------------------------------------------*/
+/* LED
+ *------------------------------------------------------------------*/
+// The board has 3 leds, but changing the number here causes OTA issues.
+#define LEDS_NUMBER           1
+#define LED_PRIMARY_PIN       _PINNUM(0, 26)
+#define LED_STATE_ON          0
+
+#define NEOPIXELS_NUMBER      0
+
+/*------------------------------------------------------------------*/
+/* BUTTON
+ *------------------------------------------------------------------*/
+#define BUTTONS_NUMBER        2
+#define BUTTON_1              _PINNUM(0, 18)
+// Button 2 is defined as D1 from expansion board.
+#define BUTTON_2              _PINNUM(0, 3)
+#define BUTTON_PULL           NRF_GPIO_PIN_PULLUP
+
+//--------------------------------------------------------------------+
+// BLE OTA
+//--------------------------------------------------------------------+
+#define BLEDIS_MANUFACTURER   "Seeed"
+#define BLEDIS_MODEL          "XIAO nRF52840 S340"
+
+//--------------------------------------------------------------------+
+// USB
+//--------------------------------------------------------------------+
+#define USB_DESC_VID           0x2886
+#define USB_DESC_UF2_PID       0x0044
+#define USB_DESC_CDC_ONLY_PID  0x0044
+
+//------------- UF2 -------------//
+#define UF2_PRODUCT_NAME   "Seeed XIAO nRF52840 S340"
+#define UF2_VOLUME_LABEL   "XIAO-BOOT"
+#define UF2_BOARD_ID       "nRF52840-SeeedXiao-v1"
+#define UF2_INDEX_URL      "https://www.seeedstudio.com/"
+
+#endif // _XIAO_BLE_S340
diff --git a/src/boards/xiao_nrf52840_ble_s340/board.mk b/src/boards/xiao_nrf52840_ble_s340/board.mk
new file mode 100644
index 00000000..6b8a3f54
--- /dev/null
+++ b/src/boards/xiao_nrf52840_ble_s340/board.mk
@@ -0,0 +1,3 @@
+MCU_SUB_VARIANT = nrf52840
+SD_VERSION = 7.0.1
+SD_NAME = s340
diff --git a/src/boards/xiao_nrf52840_ble_s340/pinconfig.c b/src/boards/xiao_nrf52840_ble_s340/pinconfig.c
new file mode 100644
index 00000000..2a592df9
--- /dev/null
+++ b/src/boards/xiao_nrf52840_ble_s340/pinconfig.c
@@ -0,0 +1,19 @@
+#include "boards.h"
+#include "uf2/configkeys.h"
+
+__attribute__((used, section(".bootloaderConfig")))
+const uint32_t bootloaderConfig[] =
+{
+  /* CF2 START */
+  CFG_MAGIC0, CFG_MAGIC1,                       // magic
+  5, 100,                                       // used entries, total entries
+
+  204, 0x100000,                                // FLASH_BYTES = 0x100000
+  205, 0x40000,                                 // RAM_BYTES = 0x40000
+  208, (USB_DESC_VID << 16) | USB_DESC_UF2_PID, // BOOTLOADER_BOARD_ID = USB VID+PID, used for verification when updating bootloader via uf2
+  209, 0xada52840,                              // UF2_FAMILY = 0xada52840
+  210, 0x20,                                    // PINS_PORT_SIZE = PA_32
+
+  0, 0, 0, 0, 0, 0, 0, 0
+  /* CF2 END */
+};
\ No newline at end of file
diff --git a/src/boards/xiao_nrf52840_ble_sense_s340/board.h b/src/boards/xiao_nrf52840_ble_sense_s340/board.h
new file mode 100644
index 00000000..2e76ef34
--- /dev/null
+++ b/src/boards/xiao_nrf52840_ble_sense_s340/board.h
@@ -0,0 +1,68 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Ha Thach for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef _XIAO_BLE_SENSE_S340
+#define _XIAO_BLE_SENSE_S340
+
+#define _PINNUM(port, pin)    ((port)*32 + (pin))
+
+/*------------------------------------------------------------------*/
+/* LED
+ *------------------------------------------------------------------*/
+// The board has 3 leds, but changing the number here causes OTA issues.
+#define LEDS_NUMBER           1
+#define LED_PRIMARY_PIN       _PINNUM(0, 26)
+#define LED_STATE_ON          0
+
+#define NEOPIXELS_NUMBER      0
+
+/*------------------------------------------------------------------*/
+/* BUTTON
+ *------------------------------------------------------------------*/
+#define BUTTONS_NUMBER        2
+#define BUTTON_1              _PINNUM(0, 18)
+// Button 2 is defined as D1 from expansion board.
+#define BUTTON_2              _PINNUM(0, 3)
+#define BUTTON_PULL           NRF_GPIO_PIN_PULLUP
+
+//--------------------------------------------------------------------+
+// BLE OTA
+//--------------------------------------------------------------------+
+#define BLEDIS_MANUFACTURER   "Seeed"
+#define BLEDIS_MODEL          "XIAO nRF52840 Sense S340"
+
+//--------------------------------------------------------------------+
+// USB
+//--------------------------------------------------------------------+
+#define USB_DESC_VID           0x2886
+#define USB_DESC_UF2_PID       0x0045
+#define USB_DESC_CDC_ONLY_PID  0x0045
+
+//------------- UF2 -------------//
+#define UF2_PRODUCT_NAME   "Seeed XIAO nRF52840 S340"
+#define UF2_VOLUME_LABEL   "XIAO-SENSE"
+#define UF2_BOARD_ID       "nRF52840-SeeedXiaoSense-v1"
+#define UF2_INDEX_URL      "https://www.seeedstudio.com/"
+
+#endif // _XIAO_BLE_SENSE_S340
diff --git a/src/boards/xiao_nrf52840_ble_sense_s340/board.mk b/src/boards/xiao_nrf52840_ble_sense_s340/board.mk
new file mode 100644
index 00000000..6b8a3f54
--- /dev/null
+++ b/src/boards/xiao_nrf52840_ble_sense_s340/board.mk
@@ -0,0 +1,3 @@
+MCU_SUB_VARIANT = nrf52840
+SD_VERSION = 7.0.1
+SD_NAME = s340
diff --git a/src/boards/xiao_nrf52840_ble_sense_s340/pinconfig.c b/src/boards/xiao_nrf52840_ble_sense_s340/pinconfig.c
new file mode 100644
index 00000000..2a592df9
--- /dev/null
+++ b/src/boards/xiao_nrf52840_ble_sense_s340/pinconfig.c
@@ -0,0 +1,19 @@
+#include "boards.h"
+#include "uf2/configkeys.h"
+
+__attribute__((used, section(".bootloaderConfig")))
+const uint32_t bootloaderConfig[] =
+{
+  /* CF2 START */
+  CFG_MAGIC0, CFG_MAGIC1,                       // magic
+  5, 100,                                       // used entries, total entries
+
+  204, 0x100000,                                // FLASH_BYTES = 0x100000
+  205, 0x40000,                                 // RAM_BYTES = 0x40000
+  208, (USB_DESC_VID << 16) | USB_DESC_UF2_PID, // BOOTLOADER_BOARD_ID = USB VID+PID, used for verification when updating bootloader via uf2
+  209, 0xada52840,                              // UF2_FAMILY = 0xada52840
+  210, 0x20,                                    // PINS_PORT_SIZE = PA_32
+
+  0, 0, 0, 0, 0, 0, 0, 0
+  /* CF2 END */
+};
\ No newline at end of file