T-Mobile is adding a third line to its unlimited plans, angling for a competitive spot among the other major carriers. A third line can be added to T-Mobile ONE, Simple Choice, and Simple Choice No Credit plans for free after bill credits, with the option for extending that plan to a different device such as a smartwatch or tablet, or adding a hotspot.

The program is also stackable with the two-for-one T-Mobile ONE for $100 offer. It also applies to the T-Mobile @Work account, through which small businesses with up to 11 lines can also receive one prepaid line.

As with other T-Mobile plans, the top 3 percent of data users (>28 GB/month) may experience reduced speeds in times of high usage. The free line is not available for customers who have cancelled a line after Jan. 1, 2017. Users who purchased lines with varying amounts of data are eligible for a free line matching the line with the least amount of data.

The free line offer goes into effect on March 1, and can be kept as long as the user maintains a qualifying service and at least two voice lines.

“Today, I’m thanking customers by giving them one of the things they want the most – a way to connect more of their family or more of their devices all the time,” John Legere, president and CEO of T-Mobile said.