Can I use a sprint iphone 5 with a&t sim card?

Okay please read this first. Also I know the answer is out there, I've just been searching for about an hour already and haven't found a direct answer to my question.

I have Sprint. An Iphone 5. My contract is up tomorrow and want to go with go phone because I'm sick of the plans, but hear me out here.

I broke my last iphone 5 so no more than two weeks ago I went to the apple store, they just took a new iphone straight out of the box, took a sim card(which I didn't even know sprint had) out of my old phone into the new phone and there you have it my new phone was activated in minutes.

Added (1). So therein lies my base question. Cause a lot of people say sprint iphones 5 is cdma where as it seemed gsm to me in the aspect I viewed at the store.

You'll need to unlock your iphone first before you stick another carrier sim card into it.

Sprint does use GSM along with CDMA but you will not be able to use a Sprint phone on AT&T or the other way around due to the fact that they will not be able to load the ESN or Serial Number. Why not just go to Sprints contract free plan Straight Talk so you can keep your current iPhone and not have to buy a new one?

If you can unlock the phone, you can use it on AT&T as Sprint iPhone 5 is both CDMA and GSM capable. If you need reference for factory unlocking your Sprint iPhone 5, mail me.