Absolutely.
The three MNO's in the USA are the afore mentioned ATT, T-Mobile, and Verizon.
The MVNO I use in the States, Tello, piggybacks on T-Mobile. The majority of places I frequent in Phoenix have good T-Mobile coverage, hence me choosing Tello.
My interest in Smarty's roaming partners in the USA is because if Smarty do not have a roaming agreement with T-Mobile, then I may need to look at an ATT or Verizon MVNO, or the MNO's directly (As MNO's in the USA charge an arm, leg and kidney for cell phone service, MVNO's are the most cost effective option, certainly for short term stays)
As an aside, another MVNO in the States, US Mobile, has an interesting proposition. In addition to their esim offering, their starter kit contains two SIM cards, a black one which connects to Verizon cell towers and a white one, which connects to T-Mobile cell towers. Obviously, you pick the SIM that offers you the best coverage for your circumstances.
As US Mobile have recently become sponsors of Barnsley Football Club here in the UK, with their logo front and centre on the player's shirts, I do wonder if they plan to launch in the UK soon, otherwise I cant see why an MVNO in the USA would sponsor a UK professional football club. They sidestep the "Are you launching in the UK ?" question on social media ...
