T-Mobile offers voice and data services for phones and other mobile devices in the U.S. and elsewhere. The company's Go5G (formerly Magenta) plans offer unlimited calling, texting, and data throughout North America, including Mexico and Canada.

T-Mobile partners with other mobile carriers in areas where T-Mobile does not offer service. When you use your phone in one of those areas, you are roaming. There are no roaming charges for calls or data usage in these areas, but the plan has a roaming limit.

If you subscribe to T-Mobile's basic plan, you have 50GB of data allotment, but your roaming limit is 200MB of domestic data per month. You won't be charged any roaming fees, but when you reach your domestic data roaming limit, your data access while roaming will be disabled until you return to an area with T-Mobile coverage or until the start of your next billing period.

T-Mobile will send you a notification when you reach 80 percent of your monthly domestic data roaming limit. You will receive another notification when you reach 100 percent. You can also view your usage in the T-Mobile app on your device.