Yes, they can. 5G phones can use 3G too. Just like now, as you move around, your phone seamlessly connects to 3G if 4G’s not available. Soon, if you’re in a 5G area with a 5G device, you’ll be able to enjoy that super-fast 5G speed. And when you move, your phone will automatically transfer to the next best connection available, whether that’s 4G or 3G.