Three will freeze the price of calls, texts and data for five years if its mooted merger with O2 is given the green light by regulators.
The network’s UK chairman, Canning Fok, made the vow in a letter to the Financial Times, as part of a wider bid to ensure that the multi–billion pound deal goes ahead.
Fok also said that the savings made from pulling the two huge networks together would be passed on to customers.
However, it's worth noting that Fok is talking about unit prices of calls, texts and data, rather than contract pricing.
That means that while you’ll pay the same rates if you go over your allowance, monthly package costs may still change.
Regulators have already given the green light to the merger between EE and BT. But it seems that the Three-O2 deal is proving a much harder sell.