C-E-O John Leger made the announcement Thursday at an investor meeting.
Legere says the company plans to sell the phone next year, but will not offer a discount like Verizon, A-T-and-T and Sprint.
He says in exchange for buying the phone full price, for anywhere from $650 to $850, the company will offer discounted voice and data plans.
Cell phone providers usually sell the phones at a markdown, but make that money back over the course of a two-year contract.
T-Mobile has not said how the new plans would work, but say their current value plans are about $20 cheaper a month than plans that offer a lower upfront cost for the phone.
Legere says almost two-million T-Mobile subscribers use unlocked iPhones purchased from different carriers or from Apple itself.