The Apple Watch Series 3 isn’t has some significant change to the Apple Watch Series 2: a built-in digital sim card on its cellular models
movement Apple S3 dual-core processor | Built-in GPS and optional cellular | Heart rate sensor, accelerometer, barometric altimeter and gyroscope | Ambient light sensor | Direct fire speaker and microphone | Wi-Fi (802.11b/g/n 2.4GHz) | Bluetooth 4.0 | WatchOS 4 | Up to 18 hours of battery life
movement Apple S3 dual-core processor