Visit the T-Mobile store in San Marcos 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 243 Wonder World Dr Suite #104 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.