diff --git a/esphome/components/ethernet/__init__.py b/esphome/components/ethernet/__init__.py
index 3d21d6e7da..ba80af74db 100644
--- a/esphome/components/ethernet/__init__.py
+++ b/esphome/components/ethernet/__init__.py
@@ -234,21 +234,22 @@ def _is_framework_spi_polling_mode_supported() -> bool:
     return False
 
 
-def _validate_spi_interface(config: ConfigType) -> None:
+def _validate_spi_interface(config):
     """Set default SPI interface or validate user choice against the variant."""
-    from esphome.components.esp32 import get_esp32_variant
+    if not CORE.is_esp32:
+        return config
+    from esphome.components.esp32 import VARIANT_ESP32, get_esp32_variant
     from esphome.components.spi import get_hw_interface_list
 
     has_spi3 = "spi3" in sum(get_hw_interface_list(), [])
     if CONF_INTERFACE not in config:
-        # Match the original C++ variant-based defaults:
         # Only classic ESP32 defaults to spi3; all others default to spi2
-        variant = get_esp32_variant()
-        from esphome.components.esp32 import VARIANT_ESP32
-
-        config[CONF_INTERFACE] = "spi3" if variant == VARIANT_ESP32 else "spi2"
+        config[CONF_INTERFACE] = (
+            "spi3" if get_esp32_variant() == VARIANT_ESP32 else "spi2"
+        )
     elif config[CONF_INTERFACE] == "spi3" and not has_spi3:
         raise cv.Invalid("Interface 'spi3' is not available on this variant.")
+    return config
 
 
 def _validate(config):