The watch you are currently looking at is not cellular, therefore you do not need an internet provider. If you are looking to get a “cellular” Apple Watch, it must say “GPS CELLULAR” on the description. Make sure you look before you click on purchase. To answer your question, ATT, Sprint and Verizon are the providers. There may be others but not sure. The 3 I listed are the basic providers. BTW, GREAT WATCH. If you want to save some money, GPS has same functions as cellular. As long as you have your cell with u at all times, which most of us do, I’d go with the GPS version. You will also be able to answer your phone on your watch with just GPS! How ‘bout that! No I don’t work for Bestbuy. Just an honest opinion.