how can i switch my carrier to tmobile

Hello,

Start here:

How to unlock your iPhone for use with a different carrier

Good luck.

If you want to use the same phone number, use number portability.

You must inform your current carrier on time that you want to take your phone number with you to T-mobile.

Your current carrier will take care of the switch and will informs T-mobile about this.

You must declare on time, and keep in mind that you will not be able to use your number for a few days. This all depends on where you live.

If the SIM format is different, visit or contact your 'new' carrier and request a replacement SIM card, normally it is free.

You can do this if you have a carrier unlocked iPhone.

Otherwise, you must contact your current carrier to discuss outstanding repayment costs.