diff --git a/ports/esp32/boards/GENERIC_S2/mpconfigboard.h b/ports/esp32/boards/GENERIC_S2/mpconfigboard.h
index 01ac2ce58e..c4f86a8fc6 100644
--- a/ports/esp32/boards/GENERIC_S2/mpconfigboard.h
+++ b/ports/esp32/boards/GENERIC_S2/mpconfigboard.h
@@ -3,3 +3,6 @@
 
 #define MICROPY_PY_BLUETOOTH                (0)
 #define MICROPY_HW_ENABLE_SDCARD            (0)
+
+// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
+#define MICROPY_HW_ENABLE_UART_REPL         (1)
diff --git a/ports/esp32/boards/GENERIC_S3/mpconfigboard.h b/ports/esp32/boards/GENERIC_S3/mpconfigboard.h
index 3540e5a855..b8f5fb2560 100644
--- a/ports/esp32/boards/GENERIC_S3/mpconfigboard.h
+++ b/ports/esp32/boards/GENERIC_S3/mpconfigboard.h
@@ -3,5 +3,8 @@
 
 #define MICROPY_PY_MACHINE_DAC              (0)
 
+// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
+#define MICROPY_HW_ENABLE_UART_REPL         (1)
+
 #define MICROPY_HW_I2C0_SCL                 (9)
 #define MICROPY_HW_I2C0_SDA                 (8)
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.h b/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.h
index beb796dd9e..f9126c98d7 100644
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.h
+++ b/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.h
@@ -4,5 +4,8 @@
 #define MICROPY_PY_BLUETOOTH                (0)
 #define MICROPY_PY_MACHINE_DAC              (0)
 
+// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
+#define MICROPY_HW_ENABLE_UART_REPL         (1)
+
 #define MICROPY_HW_I2C0_SCL                 (9)
 #define MICROPY_HW_I2C0_SDA                 (8)
diff --git a/ports/esp32/main.c b/ports/esp32/main.c
index a1c27c0a26..f833c95018 100644
--- a/ports/esp32/main.c
+++ b/ports/esp32/main.c
@@ -92,7 +92,8 @@ void mp_task(void *pvParameter) {
     usb_init();
     #elif CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
     usb_serial_jtag_init();
-    #else
+    #endif
+    #if MICROPY_HW_ENABLE_UART_REPL
     uart_stdout_init();
     #endif
     machine_init();
diff --git a/ports/esp32/mphalport.c b/ports/esp32/mphalport.c
index 41e6e6ec00..aab534937e 100644
--- a/ports/esp32/mphalport.c
+++ b/ports/esp32/mphalport.c
@@ -111,7 +111,8 @@ void mp_hal_stdout_tx_strn(const char *str, size_t len) {
     usb_tx_strn(str, len);
     #elif CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
     usb_serial_jtag_tx_strn(str, len);
-    #else
+    #endif
+    #if MICROPY_HW_ENABLE_UART_REPL
     uart_stdout_tx_strn(str, len);
     #endif
     if (release_gil) {
diff --git a/ports/esp32/uart.h b/ports/esp32/uart.h
index f32d5cf342..e3c7482e7b 100644
--- a/ports/esp32/uart.h
+++ b/ports/esp32/uart.h
@@ -28,6 +28,11 @@
 #ifndef MICROPY_INCLUDED_ESP32_UART_H
 #define MICROPY_INCLUDED_ESP32_UART_H
 
+// Whether to enable the REPL on a UART.
+#ifndef MICROPY_HW_ENABLE_UART_REPL
+#define MICROPY_HW_ENABLE_UART_REPL (!CONFIG_USB_ENABLED && !CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG)
+#endif
+
 #ifndef MICROPY_HW_UART_REPL
 #define MICROPY_HW_UART_REPL (UART_NUM_0)
 #endif