Can you unlock a sprint iPhone 4s to use on tmobile?

It also has a bad esn

I don't think so, they both have different cell phone service

sprint is cdma and t-mobile is gsm

gsm is used worldwide with other gsm carriers, but cdma only has a few carriers that have the same service.cdma is commonly found in north america and some other regions in the world, therefore, you can't unlock it and use it on tmobile

you can unlock it and then move to metropcs, verizon wireless, virgin mobile, or other carriers that are cdma