diff --git a/esphome/components/serial_proxy/serial_proxy.cpp b/esphome/components/serial_proxy/serial_proxy.cpp
index 2ab0d4ebb4..c1c1510643 100644
--- a/esphome/components/serial_proxy/serial_proxy.cpp
+++ b/esphome/components/serial_proxy/serial_proxy.cpp
@@ -130,17 +130,26 @@ SerialProxyResult SerialProxy::configure(api::APIConnection *api_connection, uin
     return SerialProxyResult::SERIAL_PROXY_RESULT_NOT_SUPPORTED;
   }
 
-  // Apply validated parameters
-  uart_comp->set_baud_rate(baudrate);
-  uart_comp->set_stop_bits(stop_bits);
-  uart_comp->set_data_bits(data_size);
-
-  // Map parity value to UARTParityOptions
+  // Skip a no-op reconfigure. Clients routinely re-send identical settings on every
+  // port open, and on a USB UART each apply is a CDC SET_LINE_CODING control transfer.
+  // Some bridges watch line-coding changes as a signalling channel (a magic baud
+  // sequence to enter a bootloader, say), so redundant applies are not harmless.
   static const uart::UARTParityOptions PARITY_MAP[] = {
       uart::UART_CONFIG_PARITY_NONE,
       uart::UART_CONFIG_PARITY_EVEN,
       uart::UART_CONFIG_PARITY_ODD,
   };
+  if (uart_comp->get_baud_rate() == baudrate && uart_comp->get_stop_bits() == stop_bits &&
+      uart_comp->get_data_bits() == data_size && uart_comp->get_parity() == PARITY_MAP[parity]) {
+    ESP_LOGV(TAG, "Settings unchanged, skipping reconfigure [%" PRIu32 "]", this->instance_index_);
+    return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
+  }
+
+  // Apply validated parameters
+  uart_comp->set_baud_rate(baudrate);
+  uart_comp->set_stop_bits(stop_bits);
+  uart_comp->set_data_bits(data_size);
+
   uart_comp->set_parity(PARITY_MAP[parity]);
 
   // load_settings() is available on ESP8266 and ESP32 platforms