Both aim to cover 98% of the UK population.
Mobile networks Vodafone and O2 have launched their first 4G data services in cities across the UK.
O2 will initally offer 4G services in London, Leeds and Bradford, while Vodafone’s services will begin its rollout to some parts of London. Both networks ultimately plan to offer 4G coverage to 98% of the UK population.
The rivals said they intend to offer services in 13 cities including London, Birmingham, Bradford, Coventry, Edinburgh, Glasgow, Leeds, Leicester, Liverpool, Manchester, Newcastle, Nottingham and Sheffield by the end of 2013.
The latest 4G offerings rival EE, which has been offering super-fast mobile data in the UK since October 2012.
Vodafone is also planning to build high-speed 4G networks capable of transmitting data-hungry videos to about 40% of its network in five major European markets, including the UK, by March 2014.
EE also revealed plans to double its 4G speed in 10 UK cities, reaching 80Mbps, with average speeds raising to over 20Mbps.
4G networks are claimed to offer data services to smartphone users up to 10 times more rapidly than standard 3G services.