- Three companies own the UK's mobile networks in 2026: BT's EE, Virgin Media O2 and VodafoneThree, which runs the Vodafone and Three brands after their 2025 merger.
- Every SIM-only brand rents space on one of those networks: giffgaff, Tesco Mobile and Sky Mobile use O2, iD Mobile and Smarty use Three, and Lebara and VOXI use Vodafone.
- VodafoneThree is combining its two networks, so many Vodafone and Three customers now connect automatically to whichever has the stronger signal.
- You can switch network and keep your number by texting PAC to 65075, and from April 2026 you can take an unresolved complaint to a free ombudsman scheme after six weeks.
- UK networks have retired 3G and will switch off 2G by 2033 at the latest, so very old phones that cannot make 4G calls may stop working.
The best mobile networks in the UK in 2026 are EE for broad coverage and a fast-growing 5G standalone network, Vodafone for its combined network with Three, and O2 for flexible contracts and strong perks. For SIM-only value, giffgaff, Tesco Mobile, iD Mobile and Smarty use those same masts with simpler plans and fewer strings attached.
The market has been reshaped. Vodafone and Three merged in 2025 to form VodafoneThree, leaving three companies that own mobile networks: BT’s EE, Virgin Media O2 and VodafoneThree. Every other brand is an MVNO, or mobile virtual network operator: a provider that rents capacity on one of those networks rather than building its own, so its coverage is essentially that of its host.
This list ranks ten networks and SIM-only brands that matter to UK buyers, explains which network each one uses and who it suits. It is for anyone coming to the end of a contract, buying a phone outright or trying to cut the family’s mobile bills.
How we ranked this list
We compared publicly documented information: coverage on each operator’s own checker and on Ofcom’s mobile coverage checker, 5G and 5G standalone availability, eSIM and Wi-Fi calling support, roaming options in Europe and further afield, the choice between contracts and rolling SIM-only plans, and how customers can get help and escalate complaints. We also considered widely reported customer feedback and the changes following the VodafoneThree merger.
We did not carry out our own coverage or speed tests, and we do not quote prices or data allowances, which change constantly. Use Ofcom’s checker and each network’s postcode map before you switch.
The Top 10 Mobile Networks
1. EE
Best for: broad coverage and fast-growing 5G standalone
EE, owned by BT Group, runs one of the UK’s largest 4G and 5G networks and is often the first choice for people who travel widely or live outside big towns. It has been rolling out 5G standalone, which it markets as 5G+, to hundreds of towns and cities. 5G standalone (5G SA) means 5G running on its own dedicated 5G core rather than leaning on a 4G core, which can make connections more responsive on compatible phones.
EE supports eSIM and Wi-Fi calling, sells both phone contracts and SIM-only plans, and backs its app and online help with a large chain of shops. It also hosts other brands, including BT Mobile, so you can use its masts through more than one provider.
The main trade-offs are cost and extras. EE tends to sit at the premium end of the market, roaming in Europe usually comes as a paid add-on rather than being included, and access to 5G+ depends on your plan and phone. If coverage is your top priority, especially in rural areas, EE is the network to check first on Ofcom’s coverage checker.
Official site: EE
- Broad 4G and 5G network
- Expanding 5G standalone (5G+)
- Large chain of shops
- Premium end of the market
- EU roaming usually an add-on
2. Vodafone
Best for: a combined network with Three and 5G Ultra
Vodafone is now part of VodafoneThree, the company formed when Vodafone UK and Three UK merged in 2025. The Competition and Markets Authority cleared the deal with binding commitments on network investment, and the combined business is merging the two networks. Following upgrades completed in 2025 and 2026, many Vodafone and Three customers now connect automatically to whichever of the two grids has the stronger signal, which has filled in not-spots for both brands.
Vodafone was the first UK operator to launch 5G standalone, under the 5G Ultra name, and it supports eSIM, Wi-Fi calling and a wide range of contracts and SIM-only deals. It has a large high-street presence, and its roaming options cover Europe and destinations further afield. Vodafone also hosts SIM-only brands such as VOXI and Lebara, so you can use its network without a long contract.
Integrating two large networks takes years, so improvements arrive unevenly and some areas will see changes sooner than others. Plans and extras can also be complex to compare. Even so, Vodafone customers stand to gain most as the merged network takes shape.
Official site: Vodafone
- Can use Three's masts too
- First UK 5G standalone launch
- Hosts VOXI and Lebara
- Network merger still in progress
- Plans can be complex
3. O2
Best for: flexible contracts and Priority perks
O2 is owned by Virgin Media O2, a joint venture of Liberty Global and Telefónica, and it hosts more of the UK’s big SIM-only brands than any other network, including giffgaff, Tesco Mobile and Sky Mobile. Alongside its 4G and 5G network, it has been upgrading towns and cities to 5G standalone and adding small cells to boost capacity in busy areas.
O2’s Custom Plans split the cost of your phone from your airtime, so you choose how long to spread the device payments and are not stuck paying for a handset you already own once it is paid off. It supports eSIM and Wi-Fi calling, and the O2 Priority app gives customers ticket presales and other perks. Virgin Media broadband customers can also bundle mobile with their home services.
O2 was the last of the big networks to finish switching off 3G, so if you still use a very old phone, check it can make 4G calls. The best perks are tied to O2’s own contracts rather than its SIM-only partners, and, as with any network, coverage varies by postcode, so check the map for home and work.
Official site: O2
- Separate phone and airtime plans
- O2 Priority perks
- Hosts many SIM-only brands
- Best perks tied to contracts
- Check postcode coverage first
4. Three
Best for: data-hungry users on the VodafoneThree grid
Three continues as a separate consumer brand inside VodafoneThree, and its customers share in the merged network: many can now connect to Vodafone’s masts automatically where that signal is stronger. Three built its reputation on generous data and was an early 5G operator with a large stock of 5G spectrum, which still makes it a natural fit for people who stream and tether heavily.
Three supports eSIM and Wi-Fi calling and sells both contracts and SIM-only plans, including rolling monthly options. Its Go Roam add-ons and plan extras cover travel in Europe and further afield. Through VodafoneThree it also owns the SIM-only brand Smarty, and it hosts Currys’ iD Mobile, so its network reaches a wide range of budget users.
In the past, Three’s indoor and rural coverage drew criticism compared with EE and Vodafone, and the merger is the main fix for that. The benefits are rolling out over time, so check the latest coverage map for your postcode rather than relying on old reputations, and check whether roaming is included or charged by the day on the plan you choose.
Official site: Three
- Shares the merged Vodafone grid
- Strong focus on data and 5G
- Rolling monthly SIM-only plans
- Merger benefits arriving slowly
- Roaming terms vary by plan
5. giffgaff
Best for: no-contract SIM-only on O2’s network
giffgaff is a SIM-only and phone brand owned by Virgin Media O2 that runs on O2’s network, including 5G. It made its name with monthly plans, called goodybags, that you can change or cancel at any time, and it still offers those rolling plans alongside newer fixed-term deals for people who want to lock in a plan for longer.
giffgaff supports eSIM, so you can switch to it quickly, and it finished rolling out Wi-Fi calling in 2024. It also sells new and refurbished phones, has added full fibre broadband, and is known for its community forum, where members answer each other’s questions. Because it shares O2’s network, its coverage is effectively O2’s coverage, including O2’s 5G.
The trade-offs are that support is mainly online and through the community rather than in shops, and its roaming terms for Europe have changed over the years, so check the current policy before you travel. If you want O2’s coverage without a contract and you are comfortable managing your account online, giffgaff is one of the safest picks.
Official site: giffgaff
- Uses O2's 4G and 5G network
- Rolling monthly plans
- eSIM and Wi-Fi calling
- Mainly online support
- Check current EU roaming terms
6. Tesco Mobile
Best for: Clubcard holders who want O2 coverage
Tesco Mobile is a 50:50 joint venture between Tesco and Virgin Media O2, which the partners renewed in 2024 for another ten years. It runs on O2’s network, including 5G, and is one of the UK’s largest virtual networks, with shops in many Tesco stores as well as online sales.
Its big draw is the link with Tesco Clubcard, which brings member-only deals and rewards for regular Tesco shoppers. Tesco Mobile sells phone contracts, SIM-only plans and pay as you go, supports eSIM, and offers Wi-Fi calling for pay monthly customers on compatible phones, working best on handsets bought from Tesco Mobile. It also lets you set spending caps so you cannot run up unexpected charges.
eSIM setup is less slick than at some rivals, as it can require a call or a store visit, and roaming terms vary by plan, so check the current details before you travel. If you shop at Tesco and O2 covers your area well, Tesco Mobile is often the most rewarding way to use that network, especially for families who want contracts with predictable bills.
Official site: Tesco Mobile
- O2 coverage with Clubcard perks
- Shops inside Tesco stores
- Spending caps to control bills
- eSIM setup less streamlined
- Wi-Fi calling depends on plan
7. Sky Mobile
Best for: Sky TV and broadband households
Sky Mobile is Sky’s mobile service and runs on O2’s network, including 5G. It is aimed mainly at households that already have Sky TV or broadband, letting you manage mobile alongside your other Sky services in one account.
Like O2, Sky splits your phone and your airtime into separate plans, so you can change your airtime without being tied to a handset deal. Its Piggybank feature lets you save unused data for later instead of losing it at the end of the month, and Sky refreshed the feature in late 2025. Sky Mobile supports eSIM, offers roaming options for Europe and beyond, and sells both phone contracts and SIM-only plans.
Sky Mobile is less compelling if you are not already a Sky customer, and getting an eSIM can take an extra step because new customers may need to start with a physical SIM. Wi-Fi calling works most reliably on phones bought from Sky. For Sky homes that want one account and O2 coverage, it is a sensible choice, and the Piggybank is a genuinely useful extra for anyone whose data use varies.
Official site: Sky Mobile
- O2 coverage with 5G
- Piggybank saves unused data
- Separate phone and airtime plans
- Best value for Sky customers
- eSIM may need an extra step
8. iD Mobile
Best for: Currys shoppers on Three’s network
iD Mobile is the virtual network run by electricals retailer Currys, and it uses the VodafoneThree network through Three, including 5G. It has grown quickly and sells through Currys stores as well as online, which makes it easy to pair a new phone or tablet with a plan in one visit.
iD Mobile supports eSIM on compatible phones and offers built-in Wi-Fi calling, with no separate app needed. Many of its plans let you roll unused data over to the next month and set a spending cap, and it offers phone contracts as well as SIM-only plans on rolling monthly or fixed terms, plus roaming add-ons for trips abroad.
Because it rides on Three’s network, coverage follows Three’s map, which is improving as VodafoneThree combines its networks but can still be weaker indoors in some areas. Support is a mix of online help and in-store advice at Currys. If you want a no-nonsense SIM-only deal or are already buying a phone at Currys, iD Mobile is well worth comparing against the bigger brands.
Official site: iD Mobile
- eSIM and Wi-Fi calling
- Data rollover on many plans
- Buy in Currys stores
- Coverage tied to Three's map
- Fewer premium extras
9. Smarty
Best for: simple rolling SIM-only plans
Smarty is a SIM-only brand owned by Three, now part of VodafoneThree, and it runs on Three’s network, including 5G. Its appeal is simplicity: plans roll month to month with no long contract, and everything is managed online or in its app, so there is very little to think about once you are set up.
Smarty added eSIM in 2025, so new customers can get connected quickly on a compatible phone, and its plans include Wi-Fi calling, which helps in homes with weak indoor signal. It offers a small, clear range of plans rather than dozens of bundles and add-ons, and some plans include roaming in Europe, so check the details if you travel.
Like iD Mobile, Smarty’s coverage follows Three’s network, which is benefiting from the merger with Vodafone. Support is online only, with no shops, and there are fewer extras than on the bigger networks. If you just want a straightforward SIM-only plan you can cancel in any month, and Three’s network works where you live, Smarty is hard to beat for simplicity.
Official site: Smarty
- Rolling monthly plans
- eSIM since 2025
- Wi-Fi calling included
- Online-only support
- Few extras or perks
10. Lebara
Best for: calling family and friends abroad
Lebara is a SIM-only MVNO on Vodafone’s network, including 5G, built around people who regularly call friends and family in other countries. Many of its plans include international minutes to a set list of countries, so you do not need a separate calling app or card for most calls home.
It offers rolling monthly SIM-only plans that you can cancel at any time, supports 4G calling and Wi-Fi calling on compatible phones, and lets you manage most things through its app. Because it uses Vodafone’s network, Lebara customers get the same national coverage map as Vodafone’s own customers, although extras such as premium 5G features can differ.
eSIM support has been limited in the UK, with Lebara rolling it out in stages for selected devices, so check whether your phone is eligible before you order. Support is mostly online and by phone, with no Lebara shops of its own. If international calling is a big part of your phone use, Lebara is one of the most practical options; if not, VOXI and Smarty are simpler alternatives.
Official site: Lebara
- International minutes on many plans
- Vodafone network with 5G
- Rolling monthly plans
- eSIM support still limited
- No shops of its own
UK network features compared
How to choose between mobile networks in the UK
Start with coverage where you spend the most time. Ofcom’s mobile coverage checker shows predicted indoor and outdoor coverage from EE, O2, Vodafone and Three by postcode, and each network has its own map. Because every SIM-only brand uses one of those networks, the coverage you get from, say, giffgaff is essentially O2’s.
Who uses which network
- EE: EE itself, BT Mobile and several smaller brands.
- O2: O2, giffgaff, Tesco Mobile and Sky Mobile.
- Vodafone: Vodafone, VOXI and Lebara.
- Three: Three, Smarty and iD Mobile.
As VodafoneThree combines its networks, Vodafone and Three customers increasingly connect to both sets of masts.
Know your rights
- Switching: text PAC to 65075 to keep your number, or STAC to 75075 to leave without it. Your provider must reply within a minute, and you will not pay for any notice period after the switch date.
- Complaints: for complaints raised from 8 April 2026, if your provider has not fixed the problem within six weeks, or sends a deadlock letter, you can take it to a free Ofcom-approved scheme: the Communications Ombudsman or CISAS.
- Older phones: 3G has been switched off and 2G will go by 2033 at the latest, so a phone that cannot make 4G (VoLTE) calls may lose service.
- Locked phones: providers can no longer sell you a phone that is locked to their network.
Frequently asked questions
Which is the best mobile network in the UK?
It depends on coverage where you live. EE is the strongest all-rounder for broad coverage and 5G standalone, Vodafone is improving as it combines its network with Three, and O2 offers flexible contracts and the widest choice of SIM-only brands. Check Ofcom's coverage checker for your postcodes, then pick the network, or a SIM-only brand on it, that suits your needs.
What happened to Vodafone and Three?
Vodafone UK and Three UK merged in 2025 to form VodafoneThree, after the Competition and Markets Authority cleared the deal with binding commitments. Both brands still sell plans, but the company is combining their networks, and many customers now connect automatically to whichever network has the stronger signal. Smarty, VOXI, iD Mobile and Lebara continue to run on the merged company's networks.
What is an MVNO?
An MVNO, or mobile virtual network operator, is a mobile brand that does not own its own masts. It rents capacity from a network such as EE, O2 or VodafoneThree and sells its own plans. giffgaff, Tesco Mobile, Sky Mobile, iD Mobile, Smarty and Lebara are all MVNOs. You get the host network's coverage, usually with simpler plans, though some features can differ.
How do I switch mobile network and keep my number?
Text PAC to 65075 from your current phone. Your provider must text back a PAC code, along with any early exit fees you would owe, and the code lasts 30 days. Give it to your new provider, which will complete the switch, usually within one working day. If you do not want to keep your number, text STAC to 75075 instead.
What is 5G standalone?
5G standalone, often shortened to 5G SA, is 5G that runs on its own dedicated 5G core network instead of relying on a 4G core. It can make connections more responsive and supports newer network features. In the UK, EE markets it as 5G+, Vodafone calls it 5G Ultra and O2 is also expanding it. You need a compatible phone and, on some networks, an eligible plan.
Final verdict
For most people, the best mobile networks in the UK start with EE for coverage, Vodafone for its growing combined network with Three, and O2 for flexible contracts and perks. If you buy your phone outright, a SIM-only brand such as giffgaff, Tesco Mobile, iD Mobile or Smarty gives you the same masts with more freedom to leave.
Check Ofcom’s coverage checker before you commit, keep an eye on how the VodafoneThree merger changes coverage in your area, and remember that switching now takes a single text.
Sources and further reading
- Ofcom mobile coverage checker: Ofcom's free postcode checker showing predicted indoor and outdoor mobile coverage from EE, O2, Vodafone and Three.
- Switching mobile phone provider: Ofcom's guide to switching by text, including the PAC and STAC codes and what your provider must do.
- Complaints and ADR schemes: How to take an unresolved phone or broadband complaint to one of Ofcom's two approved dispute resolution schemes.
- Ofcom on the 3G switch-off: Ofcom's explanation of the end of 3G services in the UK and what it means for older phones and devices.
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