diff --git a/esphome/components/esp8266/__init__.py b/esphome/components/esp8266/__init__.py
index 77ccaf52c1..4703a72f37 100644
--- a/esphome/components/esp8266/__init__.py
+++ b/esphome/components/esp8266/__init__.py
@@ -28,6 +28,8 @@ from .const import (
     KEY_ESP8266,
     KEY_FLASH_SIZE,
     KEY_PIN_INITIAL_STATES,
+    KEY_SERIAL1_REQUIRED,
+    KEY_SERIAL_REQUIRED,
     KEY_WAVEFORM_REQUIRED,
     esp8266_ns,
 )
@@ -271,6 +273,7 @@ async def to_code(config):
 
     CORE.add_job(add_pin_initial_states_array)
     CORE.add_job(finalize_waveform_config)
+    CORE.add_job(finalize_serial_config)
 
 
 @coroutine_with_priority(CoroPriority.WORKAROUNDS)
@@ -286,6 +289,24 @@ async def finalize_waveform_config() -> None:
         cg.add_build_flag("-DUSE_ESP8266_WAVEFORM_STUBS")
 
 
+@coroutine_with_priority(CoroPriority.WORKAROUNDS)
+async def finalize_serial_config() -> None:
+    """Exclude unused Arduino Serial objects from the build.
+
+    This runs at WORKAROUNDS priority (-999) to ensure all components
+    have had a chance to call enable_serial() or enable_serial1() first.
+
+    The Arduino ESP8266 core defines two global Serial objects (32 bytes each).
+    By adding NO_GLOBAL_SERIAL or NO_GLOBAL_SERIAL1 build flags, we prevent
+    unused Serial objects from being linked, saving 32 bytes each.
+    """
+    esp8266_data = CORE.data.get(KEY_ESP8266, {})
+    if not esp8266_data.get(KEY_SERIAL_REQUIRED, False):
+        cg.add_build_flag("-DNO_GLOBAL_SERIAL")
+    if not esp8266_data.get(KEY_SERIAL1_REQUIRED, False):
+        cg.add_build_flag("-DNO_GLOBAL_SERIAL1")
+
+
 # Called by writer.py
 def copy_files() -> None:
     dir = Path(__file__).parent
diff --git a/esphome/components/esp8266/const.py b/esphome/components/esp8266/const.py
index 14425cde68..fec4c7a2e8 100644
--- a/esphome/components/esp8266/const.py
+++ b/esphome/components/esp8266/const.py
@@ -8,6 +8,8 @@ CONF_RESTORE_FROM_FLASH = "restore_from_flash"
 CONF_EARLY_PIN_INIT = "early_pin_init"
 KEY_FLASH_SIZE = "flash_size"
 KEY_WAVEFORM_REQUIRED = "waveform_required"
+KEY_SERIAL_REQUIRED = "serial_required"
+KEY_SERIAL1_REQUIRED = "serial1_required"
 
 # esp8266 namespace is already defined by arduino, manually prefix esphome
 esp8266_ns = cg.global_ns.namespace("esphome").namespace("esp8266")
@@ -29,3 +31,35 @@ def require_waveform() -> None:
             require_waveform()
     """
     CORE.data.setdefault(KEY_ESP8266, {})[KEY_WAVEFORM_REQUIRED] = True
+
+
+def enable_serial() -> None:
+    """Mark that Arduino Serial (UART0) is required.
+
+    Call this from components that use the global Serial object.
+    If no component calls this, Serial is excluded from the build
+    to save 32 bytes of RAM.
+
+    Example:
+        from esphome.components.esp8266.const import enable_serial
+
+        async def to_code(config):
+            enable_serial()
+    """
+    CORE.data.setdefault(KEY_ESP8266, {})[KEY_SERIAL_REQUIRED] = True
+
+
+def enable_serial1() -> None:
+    """Mark that Arduino Serial1 (UART1) is required.
+
+    Call this from components that use the global Serial1 object.
+    If no component calls this, Serial1 is excluded from the build
+    to save 32 bytes of RAM.
+
+    Example:
+        from esphome.components.esp8266.const import enable_serial1
+
+        async def to_code(config):
+            enable_serial1()
+    """
+    CORE.data.setdefault(KEY_ESP8266, {})[KEY_SERIAL1_REQUIRED] = True
diff --git a/esphome/components/logger/__init__.py b/esphome/components/logger/__init__.py
index f1d714a810..c1b3069bf9 100644
--- a/esphome/components/logger/__init__.py
+++ b/esphome/components/logger/__init__.py
@@ -339,19 +339,15 @@ async def to_code(config):
 
     # Add defines for which Serial object is needed (allows linker to exclude unused)
     if CORE.is_esp8266:
+        from esphome.components.esp8266.const import enable_serial, enable_serial1
+
         hw_uart = config.get(CONF_HARDWARE_UART, UART0)
         if has_serial_logging and hw_uart in (UART0, UART0_SWAP):
             cg.add_define("USE_ESP8266_LOGGER_SERIAL")
-            # Exclude Serial1 from Arduino build
-            cg.add_build_flag("-DNO_GLOBAL_SERIAL1")
+            enable_serial()
         elif has_serial_logging and hw_uart == UART1:
             cg.add_define("USE_ESP8266_LOGGER_SERIAL1")
-            # Exclude Serial from Arduino build
-            cg.add_build_flag("-DNO_GLOBAL_SERIAL")
-        else:
-            # No serial logging - exclude both
-            cg.add_build_flag("-DNO_GLOBAL_SERIAL")
-            cg.add_build_flag("-DNO_GLOBAL_SERIAL1")
+            enable_serial1()
 
     if (
         (CORE.is_esp8266 or CORE.is_rp2040)
diff --git a/esphome/components/uart/__init__.py b/esphome/components/uart/__init__.py
index 9baa6ebd81..9e8917419d 100644
--- a/esphome/components/uart/__init__.py
+++ b/esphome/components/uart/__init__.py
@@ -378,6 +378,28 @@ async def to_code(config):
     if CONF_DEBUG in config:
         await debug_to_code(config[CONF_DEBUG], var)
 
+    # ESP8266: Enable the Arduino Serial objects that might be used based on pin config
+    # The C++ code selects hardware serial at runtime based on these pin combinations:
+    # - Serial (UART0): TX=1 or null, RX=3 or null
+    # - Serial (UART0 swap): TX=15 or null, RX=13 or null
+    # - Serial1: TX=2 or null, RX=8 or null
+    if CORE.is_esp8266:
+        from esphome.components.esp8266.const import enable_serial, enable_serial1
+
+        tx_num = config[CONF_TX_PIN][CONF_NUMBER] if CONF_TX_PIN in config else None
+        rx_num = config[CONF_RX_PIN][CONF_NUMBER] if CONF_RX_PIN in config else None
+
+        # Check if this config could use Serial (UART0 regular or swap)
+        if (tx_num is None or tx_num in (1, 15)) and (
+            rx_num is None or rx_num in (3, 13)
+        ):
+            enable_serial()
+            cg.add_define("USE_ESP8266_UART_SERIAL")
+        # Check if this config could use Serial1
+        if (tx_num is None or tx_num == 2) and (rx_num is None or rx_num == 8):
+            enable_serial1()
+            cg.add_define("USE_ESP8266_UART_SERIAL1")
+
     CORE.add_job(final_step)
 
 
diff --git a/esphome/components/uart/uart_component.h b/esphome/components/uart/uart_component.h
index fd528e228f..ea6e1562f4 100644
--- a/esphome/components/uart/uart_component.h
+++ b/esphome/components/uart/uart_component.h
@@ -189,10 +189,10 @@ class UARTComponent {
   size_t rx_buffer_size_;
   size_t rx_full_threshold_{1};
   size_t rx_timeout_{0};
-  uint32_t baud_rate_;
-  uint8_t stop_bits_;
-  uint8_t data_bits_;
-  UARTParityOptions parity_;
+  uint32_t baud_rate_{0};
+  uint8_t stop_bits_{0};
+  uint8_t data_bits_{0};
+  UARTParityOptions parity_{UART_CONFIG_PARITY_NONE};
 #ifdef USE_UART_DEBUGGER
   CallbackManager<void(UARTDirection, uint8_t)> debug_callback_{};
 #endif
diff --git a/esphome/components/uart/uart_component_esp8266.cpp b/esphome/components/uart/uart_component_esp8266.cpp
index c78daa7462..504d494e2e 100644
--- a/esphome/components/uart/uart_component_esp8266.cpp
+++ b/esphome/components/uart/uart_component_esp8266.cpp
@@ -75,6 +75,7 @@ void ESP8266UartComponent::setup() {
   // is 1 we still want to use Serial.
   SerialConfig config = static_cast<SerialConfig>(get_config());
 
+#ifdef USE_ESP8266_UART_SERIAL
   if (!ESP8266UartComponent::serial0_in_use && (tx_pin_ == nullptr || tx_pin_->get_pin() == 1) &&
       (rx_pin_ == nullptr || rx_pin_->get_pin() == 3)
 #ifdef USE_LOGGER
@@ -100,11 +101,16 @@ void ESP8266UartComponent::setup() {
     this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
     this->hw_serial_->swap();
     ESP8266UartComponent::serial0_in_use = true;
-  } else if ((tx_pin_ == nullptr || tx_pin_->get_pin() == 2) && (rx_pin_ == nullptr || rx_pin_->get_pin() == 8)) {
+  } else
+#endif  // USE_ESP8266_UART_SERIAL
+#ifdef USE_ESP8266_UART_SERIAL1
+      if ((tx_pin_ == nullptr || tx_pin_->get_pin() == 2) && (rx_pin_ == nullptr || rx_pin_->get_pin() == 8)) {
     this->hw_serial_ = &Serial1;
     this->hw_serial_->begin(this->baud_rate_, config);
     this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
-  } else {
+  } else
+#endif  // USE_ESP8266_UART_SERIAL1
+  {
     this->sw_serial_ = new ESP8266SoftwareSerial();  // NOLINT
     this->sw_serial_->setup(tx_pin_, rx_pin_, this->baud_rate_, this->stop_bits_, this->data_bits_, this->parity_,
                             this->rx_buffer_size_);
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 1fddc426d4..69599aa4f5 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -248,7 +248,11 @@
 #define USE_ADC_SENSOR_VCC
 #define USE_ARDUINO_VERSION_CODE VERSION_CODE(3, 1, 2)
 #define USE_CAPTIVE_PORTAL
+#define USE_ESP8266_LOGGER_SERIAL
+#define USE_ESP8266_LOGGER_SERIAL1
 #define USE_ESP8266_PREFERENCES_FLASH
+#define USE_ESP8266_UART_SERIAL
+#define USE_ESP8266_UART_SERIAL1
 #define USE_HTTP_REQUEST_ESP8266_HTTPS
 #define USE_HTTP_REQUEST_RESPONSE
 #define USE_I2C