The 4 major carriers (AT&T, T-Mobile, Verizon, and Sprint) all cover Port Townsend, with varying quality. Most people agree that AT&T has the best coverage and T-Mobile is #2, but every carrier has dead spots. Your best bet is to get a phone and try it where you'll usually use it. You can borrow one from a friend, or you can sign up for a contract and return if it doesn't work out. If you don't get a good signal where you need it, you can usually return your phone without paying a penalty. Be sure to check with the carrier when you order, though.