Apple Watch series 3

Hello @Adamd1190.

If you had a separate account for the wearable you would need to pay the data plan for that in addition to the wearable add on charge. It makes more sense to add the wearable to your current data plan. If you have a single line Unlimited account, you can add a wearable without it becoming a multi-line account. Adding on a wearable line costs $10/month for the Mobile Share Flex and Unlimited and More plans.

Thanks for choosing AT&T for your smartwatch needs!

Dawn, AT&T Community Specialist