diff --git a/homeassistant/components/weatherflow/sensor.py b/homeassistant/components/weatherflow/sensor.py
index d83eda960baa..0b5fcc6dcfd4 100644
--- a/homeassistant/components/weatherflow/sensor.py
+++ b/homeassistant/components/weatherflow/sensor.py
@@ -375,6 +375,7 @@ class WeatherFlowSensorEntity(SensorEntity):
             manufacturer="WeatherFlow",
             model=device.model,
             name=device.serial_number,
+            serial_number=device.serial_number,
             sw_version=device.firmware_revision,
         )