Special Note About AT&T Phones

With most iPhones, you should be fine using it with any carrier (assuming you took the steps above, and you aren’t buying anything older than an iPhone 5). The one exception to be aware of is AT&T, which includes a secondary LTE signal that other carriers don’t have. Like using the second band on your Wi-Fi router, this second LTE signal is used by some because there’s less traffic on it, which can be faster in crowded areas. If this is a concern for you, make sure you have an iPhone model that’s compatible with AT&T’s services.