Best and worst UK mobile networks

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.

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Which mobile phone network is the best?

In our latest satisfaction survey, we spoke with 3,739 customers of 16 of the biggest contract, Sim-only and pay-as-you-go (PAYG) providers, including EE mobile review, O2 mobile review,  Three mobile review and Vodafone mobile review.

Five providers did so well that we've made them Which? Recommended Providers, and for the first time we've endorsed three networks for Great Value. Our survey reveals:

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

Mobile provider satisfaction survey results

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

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.

We do a price analysis as part of the WRP calculation. Any providers with prices higher than market averages cannot be WRPs, even if they have a great customer score.

Eligible providers must also not use inflation-based mid-contract price rises that customers are unable to exit penalty-free when the price rise occurs.

What makes a Great Value provider?

To be endorsed as a Great Value provider, a network must offer Sim-only deals that are significantly cheaper than the market average, for a good amount of data. 

We conduct a pricing analysis to work out who represents the very best value to customers, even if the entirety of their service isn't quite good enough to achieve WRP status.

Eligible providers must also not use inflation-based mid-contract price rises that customers are unable to exit penalty-free when the price rise occurs.

Who are the biggest UK mobile networks?

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

• EE mobile – Born out of the merger between T-Mobile and Orange, and now owned by BT, this telecoms giant is the largest with around 25 million customers.
• O2 mobile – Just behind EE is O2, which is owned by Spanish telecoms company Telefonica. It has around 24 million customers.
• Vodafone mobile – Despite dominating the telecoms market in other countries, Vodafone is third in the UK with around 17.5 million customers.
• Three mobile – 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 that 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 MVNOs.

• EE: 1p Mobile, BT Mobile, Lycamobile, Utility Warehouse
• O2: Giffgaff, Sky Mobile, Tesco Mobile
• Vodafone: Asda Mobile, Lebara, Talkmobile, Voxi
• Three: iD Mobile, Smarty

1p Mobile review

1p Mobile has a small selection of Sim-only bundles, along with its uniquely priced tariff, where one call-minute, one text or one MB of data cost 1p each. 

Find out how customers rated its service in our 1p Mobile review. 

Asda Mobile review

Asda Mobile has a relatively simple offering, but supplies phone and Sim-only contracts of various lengths. 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 or browse Asda Mobile Sim-only plans.

BT Mobile review

After merging with EE, BT Mobile now primarily offers EE Sim-only deals, but special offers are available to BT Broadband customers.

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

EE mobile review

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.

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

Giffgaff mobile review

Giffgaff mainly offers 30-day Sim-only plans called ‘goodybags’ and some of the lowest PAYG rates available, but has also started offering 18 month 'Good Contracts' where the price is fixed unless the customer decides to change how much data they need.

Part of the reason costs are kept so low is that there is no customer service call centre. 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 review or browse GiffGaff Sim-only plans.

iD Mobile review

Currys-owned iD Mobile is powered by the Three network and is another low-cost mobile provider, currently offering 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.

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 a provider of international prepaid calling cards, 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 more than 40 countries such as the USA, Canada, India and Australia as well as UK data and texts. Customers can also roam free in India as well as in 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.

Lycamobile review

Lycamobile offers cheap data and often has incredibly cheap sales, such as 6GB for £1 a month, or 100GB for £10 a month. It also offers a wide range of contracts including a phone.

Data deals are available for a variety of contract lengths, such as 30 day, 3 months, 6 months and 12 months. 

Find out how customers rated its service in our Lycamobile review. 

O2 mobile review

Another of the Big Four companies, O2 offers a large range of deals and can give customers the latest smartphones on the market.

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.

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 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 primarily handled through a mixture of forums and live chat. 

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

Talkmobile review

Talkmobile is another low-cost virtual network with a sparse but cost-effective offering of Sim-only deals. 

Don't expect extensive incentives, but if you're looking for a cheap, simple package of data, minutes and texts, Talkmobile might be suitable.

Find out how customers rated its service in our Talkmobile review or browse Talkmobile 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 with some good deals available.

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 lightweight 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 review

A combined services provider, Utility Warehouse is slightly different to other networks as it also offers broadband, energy, insurance and a cashback card. It's possible to bundle various different services together. 

Utility Warehouse offers just two types of mobile deal, either a value data pack (5GB), or unlimited data. 

Virgin Mobile review

As the world's first mobile virtual network operator (MVNO), Virgin Mobile offered mobile services for more than 20 years. However, since the merger of Virgin Media and O2, all Virgin Mobile customers were transferred to O2. 

It's no longer possible to join Virgin Mobile, but existing customers are still contracted to Virgin for the moment, while receiving services and support from O2.

For full details on what happened, read our article: Virgin Mobile customers being moved to O2: what you need to know.

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.

Vodafone also has 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. 

Voxi review

Launched with the intention of attracting younger generations, Voxi offers an extensive range of phone and Sim-only contracts and deals. 

Voxi's main attraction is its endless social media and video streaming incentives, where using apps such as Facebook, Instagram, Snapchat, YouTube and Netflix will not eat into your data allowance.

Find out how customers rated its service in our Voxi review or browse Voxi 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.