If you have an unlimited AT&T plan can you add a phone and it is also unlimited data usage
Call AT&T they are reasonable with their pricing. Verizon picks your pockets any chance they get. I pay for four smart phones under a family plan. I really know the difference.
Yes, but you will still need to pay for the phone you added.
You can make a family plan, but only the phone with grandfathered data plans are unlimited, not the new lines.