Here are the specs I can find for the HTC U Play:
2G bands GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2
3G bands HSDPA 850 / 900 / 1900 / 2100
4G bands LTE band 1(2100), 3(1800), 5(850), 7(2600), 8(900), 20(800), 28(700), 38(2600), 40(2300)
It is compatible with T-Mobile on 2G GSM-1900. In some areas, 2G has been depreciated to an almost unusable status, running only a couple of channels in the guard-bands of LTE band-2.
3G: Compatible in many areas on band-2 (1900) but in some areas band 4 is required for 3G service.
4G: T-Mobile has some band-4 LTE around Myrtle Beach, South Carolina. Otherwise, your phone has no 4G compatibility with T-Mobile.
T-Mobile is rapidly becoming an effectively LTE-only carrier running on bands 2, 4, 5*, 12 & 71. *Only in Myrtle Beach.
My general observation is that, if you plan to use that model phone, you'd be better off with a SIM that uses AT&T's service, like Cricket or StraightTalk. AT&T has dropped all 2G and runs 3G everywhere on bands 2 & 5 (1900 & 850). Their primary 4G band is 12/17, so you may not get 4G service in some areas but you will in most.
Thanks for the reply, I'm not very tech savvy but am now very relieved I asked the question. The area we are going is Florida so I think it's safe to say I'll have to look at an at&t plan?
In Florida you might be OK with band-2 3G & 4G but since T-Mobile doesn't provide a coverage map that shows which bands are in use in various markets, it's hard for me to give any assurances.
Are you touring Florida or going to a specific place? e.g. Miami, Orlando?
I don't know if this will help but this is what my current network works off
elow are the frequency bands used with Three:
4G: 800MHz & 1800MHz
3G: 2100MHz & 900MHz
2G: 900MHz & 1800MHz
Those bands perfectly match the capabilities of your phone. None of them is used in North America*.
*Unless this is a trivia contest, in which case I add, "Except for the St. Pierre & Miquelon islands."