Not sure since myself and the people I know all use Verizon. The signal strength is spotty in the park - Pet loop is about 2 bars. The Verizon tower is about 5 miles away. The closest AT&T tower is about 10 miles away. There is a cell phone signal amplifier on the porch of the Visitor Center at the entrance to the campground, so that would be the best spot for any cell signal....