The worst that will happen is that you may occasionally be in a dead spot and miss a call. But even then, you'll probably get the alert or voice mail a minute later. Even with our Sprint phones on our first trip, they still worked fine for keeping in touch. It just sometimes took a couple tries. Like I said, Verizon was much better. The only place we found we could not get a signal no matter what, was inside the Land pavilion. So just don't plan on going to the Soarin FP machines, then calling your spouse to tell them what the return time is. Otherwise, you'll be fine.