T-Mobile said unlimited plans will be the only option for new customers even though they are more expensive than some of its old, limited plans.
The company had said in August that it was phasing out its other plans in favor of unlimited. On Thursday, T-Mobile said those limited plans won't be sold anymore starting Jan. 22. Existing customers can keep their current plans.
While some existing customers could switch to the $70-a-month unlimited plan and save money, others would pay more, according to prices on T-Mobile's website.
Most customers who just pay for one or two lines or who have a lower-data plan—two gigabytes per line—would save money by sticking to what they have. For example, a family of four getting two gigabytes per line was paying $100 a month; with the unlimited plan, that costs $160.
T-Mobile is still trying to lure users who don't use much data by offering them a $10 credit if they use two gigabytes or less per line. A smaller rival, Google's "Project Fi," already credits customers for data they don't use.
And T-Mobile's unlimited plan isn't exactly unlimited. If the network is busy, T-Mobile may slow speeds on customers that used more than 28 gigabytes.
T-Mobile also said that wireless bills will no longer come with taxes and fees on top of advertised prices. T-Mobile said it isn't raising prices to factor in the fees.
T-Mobile announced the new policies at the CES gadget show in Las Vegas. The show runs through Sunday.
Explore further: T-Mobile phasing out data limits—but will you save money?