Looking for a new smartphone? Deciding which device to go for is only half the battle. To make calls, send texts and access mobile data, you need a physical SIM card or eSIM from a network or provider. In the UK, there have traditionally only been four networks, but that’s now gone down to three following the merger of Vodafone and Three . However, there are still dozens of different operators that use their service, so figuring out which is right for you isn’t easy. That’s where we come in. In this guide, you’ll find a detailed run-through of each of the three main networks and all of the main MVNOs (Mobile Virtual Network Operator) which use their service. By the end of this article, you’ll have a full overview of what each network provides, whether you’re looking to buy a phone on contract or paired with a SIM-only deal once bought outright. By law, all phones sold in the UK since December 2021 must be unlocked, meaning you can easily switch to a different provider. Keeping the same phone number is relatively straightforward, too. Still deciding which phone to buy? See our guides to the best budget phones , best mid-range phones and best phones overall . What’s the best phone network in the UK? First, let’s have a look at the options. There are now only three phone networks in the UK: EE O2 VodafoneThree The Vodafone and Three merger was officially completed on 31 May 2025, after being approved by the UK’s Competition and Markets Authority (CMA) regulator. The new company, known as ‘VodafoneThree’, is 51% owned by Vodafone and 49% by CKHGT, Three’s parent company. There are no big changes yet, but this is expected to affect so-called ‘piggyback’ providers (officially known as Mobile Virtual Network Operators, or MVNOs) in the long run. They rent network space from one of the companies above, but offer their own set of contracts and specific perks. Learn more in our separate article on piggyback phone networks . Here are the most popular piggybackers and the networks they use: EE – Utility Warehouse , 1pMobile , Lycamobile , Your Co-op , Ecotalk , Spusu , IQ Mobile , RWG Mobile O2 – Giffgaff , Sky Mobile , Tesco Mobile Three – iD Mobile , Smarty , FreedomPop , Honest Mobile , Superdrug Mobile Vodafone – Voxi , Asda Mobile , Lebara Mobile , Talkmobile , RWG Mobile It’s worth keeping this in mind when considering which provider you’d like to use, as coverage for the network you use may differ depending on where you are in the UK. Ofcom’s coverage checker is a useful guide, but that doesn’t guarantee a good signal. If possible, ask friends and family for their experience, or try a pay-as-you-go SIM from one of the four main networks first. Of course, the problem with having only four networks is that if one goes down, all of its piggybackers are likely to suffer the same fate. According to RootMetrics , EE offered the most reliable service in the UK in the second half of 2024, followed by Vodafone, Three and O2. Below, we’ll run through each of the ‘big three’ phone networks and all the providers which use their services. EE (including BT Mobile, Lycamobile, Utility Warehouse & more) Main network: EE Piggybackers: Utility Warehouse , 1pMobile , Lycamobile , Your Co-op , Ecotalk , Spusu , IQ Mobile , Zevvle , RWG Mobile EE’s network is comprised of the old T-Mobile and Orange frequencies, so there’s a lot of coverage nationally. According to Uswitch , 99% of the UK population is covered by 4G – the best of any network. Meanwhile, 5G is available in 50 towns and cities. Use EE’s coverage checker to see what the service will be like where you are. EE finished switching off its 3G network in February 2024. EE itself offers iPhone, Google, Samsung and Honor phones on contract . There are also lots of SIM-only deals , with prices currently starting at £18 per month and going all the way up to £48 per month. You can also choose between one-month and 24-month plans. However, EE does charge a fixed £2.59 per day to use your data for roaming in the EU and a few other countries, though 7-day (£15) and 12-day (£21.50) passes are available – see the full list on the EE website . But there are lots of other piggyback providers which use the EE network: Utility Warehouse – only two SIM-only deals available (£5 or £23 per month), free EU roaming up to 14GB per month on Unlimited or Unlimited+ plans (costs £2 per day on Essential plan) 1pMobile – SIM-only deals from £6 to £25 per month, free EU roaming Lycamobile – SIM-only deals from £2.50 to £22.50 per month, free EU roaming , dedicated international plans for China, Turkey, Kenya, Nigeria, Uganda, Pakistan, Bangladesh and Ghana Your Co-op – SIM-only deals from £11 to £39 per month, free EU roaming Ecotalk – SIM-only deals from £5 to £18 per month, roaming for £2 per day in the EU Spusu – SIM-only deals from £4.90 to £12.90 per month, free EU roaming (3GB or 10GB per month) IQ Mobile – SIM-only deals from £10 to £35 per month (requires first three months upfront), free EU roaming for up to 25% of monthly data allowance RWG Mobile – SIM-only deals from £2 to £15 per month, free EU roaming on plans over £3.50 per month, costs 1p per MB of data otherwise O2 (including Giffgaff, Sky Mobile, Tesco Mobile & more) Main network: O2 Piggybackers: Giffgaff , Sky Mobile , Tesco Mobile O2 has been operating as a phone network in the UK since 2002. And according to Uswitch , you can expect almost 99% UK 3G or 4G coverage outdoors. Understandably, 5G is more limited and generally only available in larger towns and cities. Use O2’s coverage checker to get an idea of what to expect. O2 finished switching off its 3G network in April 2024. O2 merged with Virgin Media (to make Virgin Media O2) in 2021, but there’s been no change to the core service. In fact, there are benefits available if you’d like to combine an O2 mobile contract with Virgin Media broadband in what’s known as Volt . That’s on top of the existing perks for all O2 customers: priority booking at O2 venues, shopping and experience offers and thousands of free Wi-Fi hotspots. Then there’s the big one – free EU roaming up to 25GB per month. O2 is the only one of the main networks not to have reintroduced charges after the UK left the European Union, though plenty of piggybackers offer the same perk. O2 offers iPhone, Doro, Google, HMD, Honor, Motorola, Oppo, Samsung, Sony and Xiaomi phones on contract . While SIM-only deals range from £16 to £45.49 per month, there are often free subscriptions included. Here are the piggyback providers which use the O2 network: Giffgaff – iPhone, Samsung, Google, Motorola and HMD phones on contract, SIM-only deals from £6 to £35 per month, free EU roaming up to 5GB per month, 10p per MB thereafter, includes ‘ best plan advice ‘ which suggests a different plan if it might suit you better (including those which are cheaper) Sky Mobile – iPhone, Samsung, Google, Doro, Fairphone and Nokia phones on contract, SIM-only deals from £5 to £29 per month, all spare data rolls over for up to 12 months (previously three years), roaming for £2 per day in EU and some other countries, including USA and Australia (requires a compatible phone) Tesco Mobile – iPhone, Samsung, Google, Motorola, Doro, HMD, Honor, IMO, Nokia and TCL phones on contract, SIM-only deals from £7.50 to £30 per month, cheaper Clubcard prices on some plans, free EU roaming VodafoneThree (including iD Mobile, Smarty, Voxi, Lebara Mobile & more) Vodafone / Three Main networks: Vodafone , Three Piggybackers – iD Mobile , Smarty , Honest Mobile , Superdrug Mobile , V o xi , Asda Mobile , Lebara Mobile , Talkmobile Vodafone launched way back in 1985 as the UK’s very first cellular telephone network, while Three joined the party with the advent of 3G in 2003. In 2025, the companies joined forces to create the UK’s biggest phone network. However, the changes that will affect customers are likely to be gradual. The first benefit of the partnership , known as ‘MOCN’, or ‘Multi-Operator Core Network’, has already been rolled out to existing Vodafone and Three customers. The company has also confirmed to Tech Advisor that ‘piggyback providers’ (MVNOs) will benefit “within a few months” of August 2025. According to Uswitch , Three has 99.8 3G or 4G coverage, while Vodafone’s 4G network covers 97% of the population. Combining these two should give a significant boost. Three offers iPhone, Samsung, Google, Honor, Motorola, Xiaomi and Nokia phones on contract , plus SIM-only deals ranging from £11 to £38 per month. All plans include Three+ rewards for access to event pre-sales and discounts. On Vodafone, its phones on contract include iPhone, Samsung, Google, Motorola, Honor, Doro and HMD. SIM-only deals range from a £7 per month Basics plan (4G only) to £54 per month for a premium option . Premium Three contracts include free roaming in the EU and sometimes beyond, though more affordable plans will charge you at least £2 per day extra, depending on the country. Vodafone also offers free roaming on some more expensive plans, but charges £2.57 extra per day for EU roaming (up to 25GB per month) on most. However, you can get 8-day (£15) or 15-day (£20) passes that work out cheaper. But that’s not the case for all the piggyback providers which use their networks. Here’s the selection on Three: iD Mobile – iPhone, Samsung, Google, Honor, Motorola, Nokia and Oppo phones on contract, SIM-only deals from £6 to £18 per month, unused data rolls over to next month, free EU roaming up to 30GB per month Smarty – SIM-only deals from £6 to £20 per month, get money back for unused data on some plans, free EU roaming up to 12GB per month Honest Mobile – SIM-only deals from £12.15 to £25 per month, loyalty discount of 5% per year (up to max 30%), five days of free EU roaming each month, then £2 per day thereafter (max 20GB per month). Also offers ‘ Smart SIM ‘, which lets you switch between 650 networks around the world (including all of the UK ones) for 500+ specific apps Superdrug Mobile – two SIM-only deals available (£10 or £20 per month), free EU roaming up to 12GB per month And here are the options that use the Vodafone network: Voxi – iPhone, Samsung, Google, Honor and Motorola phones on contract, SIM-only deals from £10 to £35 per month, unlimited use of selected social media apps (also music and video streaming services on some plans), EU roaming from £2.45 per day, though eight-day (£15) and 15-day (£20) passes are also available (all up to 20GB per month) Asda Mobile – iPhone, Samsung, Doro, Nokia, Motorola, HMD and TCL phones on contract, SIM-only deals from £5 to £22 per month (all plans eligible for Asda Rewards ), free EU roaming up to 5GB per month, 10p per MB thereafter Lebara – iPhone and Samsung phones on contract, SIM-only deals from £4.50 to £30 per month, free EU and India roaming (up to 30GB per month) Talkmobile – SIM-only deals from £5.95 to £11.95 per month, free EU roaming Related articles Best PAYG phone networks Best phone insurance All phone news All phone reviews Best phones