Yes. The Apple Watch Series 3 (GPS + Cellular) and newer has an AT&T mobile number and associated plan that will appear on your monthly bill. Note, the watch mobile number cannot be used for voice, data or text messaging from the watch. Please remember to complete AT&T NumberSync setup to use your watch on the AT&T cellular network with your iPhone number. With AT&T NumberSync active, calls and messages using your watch will display your AT&T iPhone number.