O2 will rollout its 4G network in the UK from the 29 August, initially offering the service to new and existing customers in London, Leeds and Bradford.
The mobile operator will be the first to go head to head with rival EE, which was given permission to use its existing network to offer 4G services since October last year.
Telefonica-owned O2 paid £550m for part of the higher-value 800MHz spectrum auctioned by regulator Ofcom in February, which should give users mobile internet speeds more than five times faster than on 3G.
The O2 network will cover 5m people as soon as it is launched later this month, with an extra 2m people added each month and plans to be live in 13 cities by the end of the year.
“The full potential of 4G is as yet unexplored, but what we can be sure of is that it will allow for a whole new world of opportunity that people are now ready for,” said Telefonica UK chief executive Ronan Dunne.
4G tariffs on the network will start at £26 per month, with additional business contracts offered for tablets and mobile broadband from launch.