T-Mobile USA + UMA phone

[Motel75]

I can confirm it works, as I use it this way on a daily basis (with a Samsung T409).

However, UMA is not without its issues. The T409 won't log on to a hotspot/router with 128-bit security, and it can't use one that requires a logon (like many hotel hotspots). T-Mobile hotspots in Germany don't work automatically like ones in the US do. After a call of several minutes duration is completed, the phone often disconnects from the hotspot and requires manual reconnection. Also, sometimes people have reported trouble in calling the number while it's on Wi-Fi.

It's possible a more sophisticated phone would solve some or all of all of these problems (the T409 was one of the first UMA models, and there has been no firmware update for it, but it can be found cheaply on eBay). Nevertheless, it's nice to be able to use my thousands of T-Mobile prepaid minutes from abroad, and to be reachable from a US number without paying roaming.