THREE is the smallest of the UK mobile operators with 12% of the UK market. They claim a 99.8% population coverage in the UK. They came into the market with the advent of 3G. For many years, in surveys of performance, THREE came around third although more recently they have seen figures up at the top and competing with EE.

In the execution of the 3G auction the government wanted to protect a new license for a new entrant into the UK market. THREE, owned by Hutchison telecoms, was the sucessfull company. They do not have a 2G network; but have extensive 3G, 4G and 5G networks. THREE are at the forefront of offerring unlimited (or at least large data allowances) at a reasonable cost, thus they have attracted large data users. Additionally THREE are marketing mobile WiFi as a true competitor to home fixed broadband.

The frequencies they use are :

Three originally were awarded frequency at 2100MHz to run their 3G network, which they still use today. In pursuit of 4G frequency, Three purchases space at 800MHz which allows them to run 4G over large areas. Three were additionally awarded frequency at 1800 MHz by OFCOM as part of the EE merger agreement in which to run their 4G network. Three purchased only 20MHz of the 3.4GHz frequency band in which to run their 5G network, the smallest of the operators. However, as a bit of forward planning, Three purchased UK-Broadband which owned a significant amount of frequency at 3.6-3.8GHz bandwidth. Together with the 5G purchase THREE has a lot of 5G frequency, but more importantly they had a large continuous block of frequency making their operation of 5G more efficient. Subsequent to the auction there was some frequency trading to allow all networks to have their 5G frequency [3.4 to 3.8GHz] in continuous blocks. Following this THREE have come out well and have a block of 100MHz of 5G frequency (plus another 20MHz block).

Three was the last of the MNO to release their 4G network, preferring to concentrate on building up HSDPA+ which was delivering the same speed as initial 4G offerrings. Now they have an extensive 4G and 5G network. Like the other operators they will be switching off their 3G network in 2024.

Three have some good deals for the consumer who wants lage amounts of data, including unlimited data calls and texts. Their CEO is promoting large data deals as he sees the mobile network as a direct competitor to WiFi and home broadband. THREE have been at the front of the drive for mobile broadband to be used whilst travelling and as an alternative to land based home broadband. THREE run a number of high street shops as well as an online presence selling devices for their network.