Three Mobile has upstaged O2 and Vodafone's 4G launch on Thursday by announcing that it will give all of its customers the new service for free, from December.
If you're on Three and you have a 4G-ready phone, you'll be upgraded at no extra cost. The update will come via a simple settings change over-the-air, with no need to get a new SIM.
Three said that the rollout will start in London, Manchester and Birmingham, but will grow to 50 cities by the end of 2014 and 98% of the UK by 2015.
Customers with unlimited data plans will also be upgraded to 4G . That potentially represents a huge boost to heavy users who are limited on O2, Vodafone and EE to a certain number of GB per month.
The question that remains is whether Three's coverage can match those of the other networks - and how many of its 1.5 million customers will be able to upgrade.
Ernest Doku, telecoms expert at uSwitch.com, said that Three will have to work hard to match EE's headstart and Vodafone/O2's added extras, but that on cost it can't currently be beaten.
"Three certainly intends to spark a price war by offering unlimited data from just £15 a month on a SIM-only plan. And with almost seven in ten consumers (68%) surveyed by uSwitch worried about racing through their allowances on 4G, Three's offering could be just what data hungry smartphone lovers are looking for," he said.