Tello historically operated on the Sprint network (and some SIM cards still do), but that's being phased out now, so all new SIM cards issued should be operating on the T-Mobile network.

Tello Mobile is a worthwhile option for those seeking a budget phone carrier with unlimited data tiers, free hot spot tethering, and prices as low as $5/month. Like Mint Mobile an ...

What You Need To Know When you sign up for Tello, you will need to purchase a SIM card in order to activate your service. The SIM card is what allows your phone to… READ FULL ARTICLE: Do I Need A Sim ...

Customer support With Tello, your initial setup will be minimal. You'll either order an eSIM online or receive a SIM card in the mail and use an accompanying QR code to set up your account in the ...