Question: will my straight talk phone work with tmobile?
Answer: Unlocking Devices Brought to Straight Talk You should be able to easily pop in a Straight Talk SIM card as long as you choose a matching service. If your phone is carrier locked to T-Mobile, purchase a T-Mobile SIM, and you'll be good to go. ... If you bring an unlocked AT&T to T-Mobile or vice versa, it should work fine.