Switching to the Un-Carrier can be exciting, but you have to know how to get set up. Here's how to activate a T-Mobile SIM card.

So you've chosen Ultra Mobile as your carrier. Before you start enjoying your plan, you need to install your SIM card – here's a step-by-step guide.

If you're a new Metro by T-Mobile customer who bought a SIM card online or in a retail store, you'll need to activate it, and we're here to help.

T-Mobile's self-service SIM managing tool is back in the T-Life app. Here's how to get it set up and transfer your own SIM cards and eSIMs on your own.

Want to install an extra SIM card in your smartphone? Here's what you need to do just that.

Want to install an extra SIM card in your iPhone 6s? Here's how to do just that.