Talk:United States/@comment-138.75.228.12-20170311144853/@comment-26674008-20170313104048

The traditional advice, was that if you're going to any rural area, that AT&T will probably have the better coverage. But T-Mobile has now built many new towers and the rural coverage isn't nearly as bad, particularly if your phone supports the LTE band 12.

However there is an important comment. There is NO GSM coverage in the Grand Canyon area, from either AT&T and T-Mobile, at all. The only providers are Verizon (not GSM) or Commnet which is a local GSM on which roam AT&T and T-Mobile postpaid (there is no roam on AT&T or T-Mobile prepaid). One can buy Commnet prepaid SIM, but this is so uncommon, it is not even featured here.

Probably in Zion and Yosemite, you'll fare ok with AT&T. T-Mobile might still be hit-or-miss.

If you're extreme dependent on good coverage for some reason, you might look to see if your phone supports Verizon and read the CDMA in USA page.