Can my sprint iPhone be used with Tmobile?

I went into Tmobile today to ask about changing my plan, I currently have Sprint and am paying month to month as my contract already ended. I was told however I wouldn't be able to use my iPhone from sprint because it doesn't use sim cards. However someone else told me that if i take my iPhone to sprint after canceling my service, they can unlock the phone. Would i be able to use my iPhone with tmobile once its unlocked?

My Sprint iPhones do have sim cards. Your's does too. Here's the problem. Sprint's current policy is never, ever unlock a phone for use on another domestic carrier-ever. They don't but will by Feb '15 due to new rules. You will have to ask someone else or Tmobile or buy online the unlock software. Why? Sprint uses CDMA signals. Tmobile uses GSM signals. Unless unlocked, that phone will never recognize Tmobile's sim card in it. February will be here soon. Best luck.

Sprint Iphones don't use sim cards. Tmobile is a GSM network, therefore they require that a phone use a sim card. So no.

Both Verizon and Sprint are CDMA carriers. Whenever you deal with a CDMA carrier their phones are only designed to be used on their network.

Your better off selling your phone and then buying an unlocked GSM iphone