Apple Watch Series 3 (GPS + Cellular) can be used without activating the cellular feature.
In order to set up and use Apple Watch Series 3 (GPS + Cellular), whether activating the cellular feature or not, you need an iPhone 6 or newer model of iPhone, running the latest version of iOS:
Apple Watch Series 3 (GPS + Cellular) includes a built-in cellular capability. This can enable certain features to be used when the watch is away from the paired iPhone, subject to various requirements as explained here:
- How to use your Apple Watch without your iPhone nearby - Apple Support
- About Bluetooth, Wi-Fi, and cellular on your Apple Watch - Apple Support
In order to use the built-in cellular feature, you would need a carrier service plan for your iPhone that specifically includes support for Apple Watch Series 3 (GPS + Cellular), including the carrier activating it on the plan. An activation fee and ongoing monthly charges may apply - contact your supported carrier for details:
If desired, Apple Watch Series 3 (GPS + Cellular) can instead be set up and used without enabling the built-in cellular capability, in which case it can be used with a compatible iPhone on any carrier's network.
When used in this way, it behaves in the same way as a GPS-only model, again as explained within the support articles linked above.