Help Can I use my current SIM card with a new phone, or do I use the card that comes with it?

[JohnJSal]

Hi all. I'm considering upgrading my S4 to an S7, and I noticed on the T-Mobile order page that it says new phones come with a "SIM Card Starter Kit." What exactly is this?

If I already have T-Mobile service and a SIM card, can I just use the one I have, or do I need to use the one that comes with the new phone? Is it the same thing?

Thanks!
John

 

[yknujssab]

You can use the same one. As long as the sim card is the same size.

 

[kate]

The Galaxy S4 has a micro-SIM, S7 uses nano-SIM card.

It's possible to cut a micro down to a nano size, but I'd recommend getting a new nano-SIM.

 

[Hadron]

^this!

Cutting a mini to a micro is possible, but micro to nano you have to cut so close to the circuits that I'd personally not bother.

The SIM is the thing that associates your account and phone number to the handset. So if you are getting a new SIM you need T-Mobile to "transfer your phone number to that SIM" (in quotes because the reality is that they associate that SIM number to your account and disable the old one, but the effect is the same). If you are upgrading through T-Mobile they should do this as part of the upgrade. If you are buying an unconnected handset and want to use it with your account you should just ask them for a new nano-SIM, tell them why and ask them to transfer your number to the new SIM (I've done this in the UK, and it's the same technology, so I'm assuming the procedure will be the same too).