Apple Watch Series 3 (GPS) requires an iPhone 5s or later with iOS 11 or later. Apple Watch Series 3 (GPS + Cellular) requires an iPhone 6 or later with iOS 11 or later. Apple Watch and iPhone service provider must be the same. Cellular is not available with all service providers. Roaming is not available outside your carrier network coverage area. Wireless service plan required for cellular service. Contact your service provider for more details.
Apple Watch Series 3 (GPS) lets you send and receive text messages, answer phone calls, and receive notifications when it's connected to your iPhone via Bluetooth and Wi-Fi. The built-in GPS works independently of your iPhone for distance, pace, and route mapping in workouts.
Apple Watch Series 3 (GPS + Cellular) has all the same features, as well as built-in cellular. It gives you the freedom to send and receive text messages, answer phone calls, and even receive notifications when you don't have your iPhone with you.
Connecting Apple Watch to a cellular network requires the same carrier as your iPhone, and we're adding carriers all the time. If your current carrier does not support Apple Watch, cellular functionality won't work until support is provided.