Once in the app, simply select "start your trial" and the app will download a virtual eSIM to provide access to the carrier's service. Like T-Mobile and Verizon, the program will utilize eSIMs to let you see how AT&T compares to your existing service while still keeping that line active.

Like similar offers from T-Mobile and Verizon, AT&T's free trial taps the eSIM function on Apple iPhones, allowing people to switch between carriers over a 30-day period.

AT&T used to dominate as one of the best phone carriers in the US. But over the past decade, there's been a lot of tough competition, and the answer to which carrier is best isn't