Does a 3 sim work on an iphone locked to t mobile?

Would my three sim work on an iphone 4s that has been locked to t mobile because i herd they work together so would the sim work?

I doubt it!

No i don't think it will work, you will need to buy a code to unlock your mobile so it can be used on any network. Most companies lock their phones so you are more inclined to stay with them because they have made it harder for you to change networks. I've had this problem and was quite disappointed when I found this as my answer. I hope this helps you, you can try and contact t mobile or search online for where to buy an iPhone unlock code.

Heard wrong. The phone is locked to T-Mobile, so no other carrier's SIM would work in it.