Will a Verizon iphone SIM card work on a T-Mobile iphone?

I wanted to know if I can put my Verizon sim card into a t-mobile iPhone and will it work? I never heard of anyone having to factory unlock a T-mobile iphone to use any carrier so I'm just curious will this work or will I need to unlock the phone?

I don't think it will work. You can try it… It'll tell you if it will work or not. You could always take the phone to your carrier to get unlocked.

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No, you can't do that. Because both are different network technology at the same time, you can use GSM carriers only on your T-Mobile locked iphone. If you want to use other network on your iphone, you will need to unlock it. For unlocking use http://www.simpleunlocking.com/apple-iphone/rs16wp9/