Visit the T-Mobile store in Alton and discover America’s largest, fastest, and most reliable 5G network. Shop our best low-cost plans with no annual service contracts - plus our best smartphones, cell phones, tablets, internet devices, and latest promotions. If you’re interested in joining the Un-carrier, our staff at 220 N Alton Blvd Suite E can assist you in the switching process. Masks are optional for fully vaccinated guests except where state or local ordinances require all guests wear a mask at all times.