diff --git a/esphome/components/uart/uart_component.h b/esphome/components/uart/uart_component.h
index 3d2a848462..c260ad3b7a 100644
--- a/esphome/components/uart/uart_component.h
+++ b/esphome/components/uart/uart_component.h
@@ -31,6 +31,8 @@ const LogString *parity_to_str(UARTParityOptions parity);
 
 class UARTComponent {
  public:
+  static constexpr size_t RX_FULL_THRESHOLD_UNSET = 0;
+
   // Writes an array of bytes to the UART bus.
   // @param data A vector of bytes to be written.
   void write_array(const std::vector<uint8_t> &data) { this->write_array(&data[0], data.size()); }
@@ -187,7 +189,6 @@ class UARTComponent {
   InternalGPIOPin *rx_pin_{};
   InternalGPIOPin *flow_control_pin_{};
   size_t rx_buffer_size_{};
-  static constexpr size_t RX_FULL_THRESHOLD_UNSET = 0;
   // ESP-IDF always sets this at codegen time via set_rx_full_threshold().
   // Other platforms (USB UART, Arduino, etc.) leave it unset.
   size_t rx_full_threshold_{RX_FULL_THRESHOLD_UNSET};