User blog:Debbieduffy/which cell phone with cover my needs

I live part of the year in honolulu and part in canada (ontario). I'm needing to buy a new cell phone and i'm considering the samsung galaxy alph or the S6. I will be buying the phone in the u.s. and using it in both countries. I use the T-mobile Ultra service in honolulu and wind when in canada for both calls and data. Can you tell me if both or which one of these phone will work on both services in both countries please.