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8 September 2021

Best and worst UK mobile networks

Want to switch mobile phone provider but don't know where to start? Our latest satisfaction survey results will help you make the right choice.
Hamse Yusuf

With people using their mobile phones more than ever, having a good mobile network with a reliable signal, good speeds and quality customer service has never been more important.

At Which?, we regularly survey customers of the biggest mobile phone networks in the UK. Our detailed analysis of different aspects of a mobile network service, including customer service and value for money, can help you make an informed choice about your next provider.

Find the best deals on mobile phones and Sim-only contracts to see how much you could save.

Which? is bringing legal action against Qualcomm. If you bought an Apple or Samsung phone after 1 October 2015, you could be affected. Find out more.

Which mobile phone network is the best?

In our latest satisfaction survey, we spoke with more than 4,000 customers of 13 of the biggest contract, Sim-only and pay-as-you-go (PAYG) providers, including EE mobile review, O2 mobile review, Vodafone mobile review and Three mobile review

Three providers did so well that we've made them Which? Recommended Providers. Our survey reveals:

  • Which mobile phone networks were rated as Which? Recommended Providers.
  • Quotes from real customers on their experiences.
  • A look at each network's UK coverage.
  • Each provider's deals and incentives.

Mobile phone provider satisfaction survey

Which? members have full access to the information in the table below. Join Which? to unlock the full details.

BrandWRP*Customer ServiceEase of ContactingValue for MoneyIncentivesCustomer Score

What makes a Which? Recommended Provider?

In order to be a Which? Recommended Provider (WRP), mobile networks have to offer more than great service to customers.

This year, we changed how we calculate WRPs in our survey and now also take cost into account. Any providers with prices costlier than market averages cannot be WRPs, even if they have a great customer score.

As this was the case for Sky Mobile, it missed out on becoming WRP.

Who are the biggest UK mobile networks?

In the UK, there are four major mobile providers, all of whom are household names when it comes to mobile networks.

  • EE mobile review – Born out of the merger between T-Mobile and Orange, and now owned by BT, this telecoms giant is the largest with around 32 million customers.
  • O2 mobile review – Just behind EE is O2, which is owned by Telefonica, a Spanish telecoms company and has around 24 million customers.
  • Vodafone mobile review – Despite dominating the telecoms market in other countries, Vodafone is third in the UK with around 17.5 million customers.
  • Three mobile review – Owned by a Hong Kong-based conglomerate, Three is the last of the big four networks with approximately 9.9 million customers in the UK.

These four networks, often called the ‘big four’, are the only ones which own slices of the UK mobile spectrum (which is the physical signal your phone receives) and, as such, other providers have to partner with one of these four mobile networks and use their signal to power their Sims, a practice known as ‘piggybacking’.

Love a bargain? We round up the best mobile phone deals each month to highlight some great discounts.

Who powers mobile networks such as GiffGaff and Tesco Mobile?

Because the big four mobile networks have a monopoly on the mobile spectrum, other networks have to partner with one of these networks to power their Sims. Providers such as these are called MVNOs (Mobile Virtual Network Operators) and examples of MVNOs include Asda Mobile and Plusnet Mobile. Our list below shows you which of the major mobile networks power some of the largest MVNO’s.

  • EE: BT Mobile, Plusnet Mobile, Virgin Mobile, Utility Warehouse
  • O2: GiffGaff, Sky Mobile, Tesco Mobile
  • Vodafone: Asda Mobile, Lebara, Voxi
  • Three: ID Mobile, Smarty

Asda Mobile review

Asda Mobile is a PAYG-bundle only provider, offering a variety of bundles. This means you can’t get contracts or Sim-only deals, and you have to pay upfront to use its services. However, it’s one of the cheaper providers out there and many customers appreciate the low-cost deals Asda Mobile offers.

Find out how customers rated its service in our Asda Mobile review

BT Mobile review

After returning to the mobile market in 2015 after acquiring EE, BT Mobile is still finding its feet in the mobile market. BT Mobile offers both contract and Sim-only deals to its customers, with BT broadband customers receiving an extra £5 off a month.

Find out how customers rated its service in our BT Mobile review or browse BT Mobile Sim-only plans.

EE mobile review

Born out of the merger between T-Mobile and Orange, and now owned by BT, telecoms giant EE is now the largest mobile phone provider in the UK. It offers a range of contract, sim-only and PAYG deals.

EE customers also get free access to the BT Sport app for the first three months as well as access to 'Smart benefit' rewards when you take out a pay-monthly deal, whether Sim-only or contract.

Find out how customers rated its service in our EE mobile review or browse EE Sim-only plans.

GiffGaff mobile review

GiffGaff has been around for almost 10 years now and has firmly established itself in the mobile network market as a low-cost, no-frills network.

GiffGaff mainly offer 30-day Sim-only plans called ‘goodybags’ and some of the lowest PAYG rates available.

Part of the reason costs is kept so low is that there is no customer service call centre and all non-account-related issues have to be raised in the GiffGaff community, where other customers help answer your questions (there are also chat agents for specific account-related issues).

Find out how customers rated its service in our Giffgaff mobile review or browse GiffGaff Sim-only plans.

iD Mobile review

Carphone Warehouse-owned iD Mobile is powered by the Three network and is another low-cost mobile provider, currently boasting some of the cheapest deals around.

iD Mobile customers can also get a contract phone with some of the latest iPhones and Samsung Galaxys available due to iD Mobile’s partnership with Carphone Warehouse.

Find out how iD Mobile customers rated its service in our ID mobile review or browse ID Mobile Sim-only plans.

Lebara mobile review

Initially founded in 2001 as an international prepaid calling cards providers and then a mobile network focusing on international calls, Lebara has revamped its sim-only offering in recent years to become a low-cost Sim-only provider.

Lebara offers Sim-only deals with a mix of UK and international calls to over 40 countries such as USA, Canada, India and Australia as well as UK data and texts. Customers also can roam free in India as well as the standard EU countries.

All packages are on a 30-day rolling plan and Lebara runs on the Vodafone network. 

Find out how customers rated its service in our Lebara Mobile review or browse Lebara Mobile Sim-only plans.

O2 mobile review

Another of the big four companies, O2 offer a large range of deals and can give customers the latest smartphones available on the market.

Refresh deals split the cost of the smartphone and airtime, meaning that you never overpay for your contract once it has finished. Also, O2's Refresh allows you to control every aspect of the deal, including length, data allowance and upfront cost.

The Priority app also allows O2 customers exclusive access to special deals, freebies and concert tickets before anyone else.

Find out how customers rated its service in our O2 mobile review or browse O2 Sim-only plans.

Plusnet Mobile review

Despite being traditionally known as a broadband provider, BT’s ownership of Plusnet means that Plusnet is also able to offer mobile services to its customers.

Although not a major player in the mobile network market, Plusnet still offer inexpensive Sim-only deals, which last 30 days and are flexible, meaning you can change your package easily, depending on your needs.

If you’re a Plusnet broadband customer, you’re able to get a data boost of 2GB.

Find out how customers rated its service in our Plusnet mobile review or browse Plusnet Mobile Sim-only plans

Sky Mobile review

Telecoms giant Sky went live with its mobile offering in 2017, using the O2 network to power its service.

Sky TV customers can get the best deals here, with unlimited streaming available if you have a Sky TV package although data rollover for up to three years is available to all customers.

Find out how customers rated its service in our Sky Mobile review or browse Sky Mobile Sim-only plans.

Smarty mobile review

As Three's low-cost virtual network, Smarty's mission is to offer ultra-cheap Sim-only packages with very little in the way of extras.

That being said, Smarty does offer three data discount plans, whereby the cost of unused data is refunded at a cost of 1p per MB, up to £3 if you use 1GB or less. Smarty's customer service and account management is 100% online and is primarily handled through a mixture of forums and live chat. 

Find out how customers rated its service in our Smarty review or browse Smarty Mobile Sim-only plans.

Tesco Mobile review

Although Tesco is best known for being the biggest supermarket chain in the UK, Tesco Mobile has grown its base to more than five million customers and has become a real contender in the mobile network market, offering some good deals to customers.

Offering the lot in terms of contract phones, Sim-only and PAYG plans, Tesco Mobile’s plans are fairly inexpensive and now include 5G plans.

Tesco Mobile customers can also collect Clubcard points with its packages and use them in-store or redeem them for vouchers to spend on special rewards.

Find out how customers rated its service in our Tesco Mobile review or browse Tesco Mobile Sim-only plans.

Three (3) mobile review

The smallest of the big four mobile networks, Three is known for offering data heavy deals for low prices.

Most plans come with Go Roam Around the World, which allows you to call and text the UK as well as use up to 12GB of your allowance in more than 70 countries, including Australia and the US, depending on the package you select.

Find out how customers rated its service in our Three mobile review or browse Three Mobile Sim-only plans.

Utility Warehouse mobile review

Utility Warehouse Mobile is a Sim-only provider who styles itself as the ‘biggest mobile provider you have never heard of’ not having any shops or engaging in any direct marketing. Utility Warehouse Mobile offer two Sim-only packages.

Utility Warehouse Mobile also offers mobile handsets on a two-year contract from as low as £1 per month, although this is a charge for the handset only and does not include a Sim plan. Utility Warehouse offer discounts to those customers who take out multiple utilities (broadband and energy, for example), also offering extra data as an added incentive to bundle your services.

Find out how customers rated its service in our Utility Warehouse mobile review.

Virgin Mobile review

As the world's first mobile virtual network operator (MVNO), Virgin Mobile have been offering mobile services for almost 20 years and uses Vodafone's network to power its mobile service.

Now under the Virgin Media umbrella, Virgin Mobile attempts to compete with the big players by offering the latest contract smartphones and Sim-only deals. Virgin Mobile customers also have the ability to use WhatsApp, Facebook Messenger and Twitter in the UK, and not use up any of their allowance, although voice and video calls through WhatsApp and Facebook Messenger are excluded.

Find out how customers rated its service in our Virgin Mobile review or browse Virgin Mobile Sim-only plans

Vodafone mobile review

Another of the four mobile giants, Vodafone has been offering its services for more than 30 years in the UK and has its own network in which to do so.

Vodafone also boasts more than 75 destinations where you can roam free of charge, including Australia, Canada and the US, more than any other UK network. Although, this is only available on the more expensive tariffs.

Find out how customers rated its service in our Vodafone mobile review or browse Vodafone Sim-only plans

Recommendations you can trust

Which? is independent – we work for you, the consumer, so you can be sure that our recommendations are only influenced by our test and survey results. We're not influenced by third parties and we don't accept freebies from product manufacturers or retailers.