Best and worst mobile networks: big four providers out-performed by smaller rivals

Smaller mobile networks impressed in our latest annual satisfaction survey, with high customer scores and incredibly cheap deals providing some positive options for customers to avoid being hit by relentless price increases.

We asked over 5,000 mobile customers about their experiences in the past 12 months and found a wide range of opinions. Generally, customers of the big four networks (EE, O2, Three and Vodafone) face higher prices, worse customer service and continue to be hit by annual price increases.

In contrast, several smaller networks are providing exceptional satisfaction to their customers. They are recognised by our endorsements, as either Which? Recommended Providers, or Great Value for Sim-only deals.

For full results of our survey, read our round-up of the best and worst UK mobile networks.

The UK’s major mobile networks compared

The big four mobile networks provide services to millions of the UK’s mobile customers. However, they did not reach the same high standards achieved by smaller providers that piggyback on their network infrastructure. 

• EE achieved the highest customer score of the big four, and put a little distance between itself and the other three. However, it managed just two four-star ratings, for network reliability and the ease of getting in touch. Roaming and incentives each received only two stars.
• O2 finds itself lumped at the bottom of the table alongside Three and Lycamobile, with a string of two star ratings. Only 65% of O2 customers said the network represented good value for money, the lowest of any network.
• Three, for a third year in a row, had not only the lowest customer score of the big four, but the lowest of any provider we rated. It also received just two-star ratings in every category.
• Vodafone received a reasonable customer score but an uninspiring set of ratings, with none higher than three stars and several two star scores thrown in, notably for customer service. While it’s now merged ownership with Three, they continue to be operated as distinct brands for now.

Keep in mind that all four networks automatically increase their prices every year. Sim-only contracts with EE, O2 and Vodafone rise by £2.50 a month each April, while Three’s increase by £1.80 to £2.30 a month depending on how much data is included.

The best mobile network providers

At the other end of the table, five networks this year were named Which? Recommended Providers (WRP).

Talkmobile - an exceptional year sees it receive the highest customer score and a set of strong ratings, with five stars for value for money and four stars for customer service being particularly impressive. For a third year running, Talkmobile is both a WRP and Great Value network, further consolidating the brand as an ideal example of what quality and value looks like in the mobile networks market. All Talkmobile Sim-only contracts come with 5GB of free EU roaming.

Giffgaff - launched in 2009 and initially just providing cheap Sim-only deals, Giffgaff has since evolved to include selling phones and fixed price contracts with flexible data allowances. The price won’t increase unless you want more data, equally you can reduce the data to lower the price. A five star rating for value for money shows that customers continue to think positively of its prices, even with the expanded range. Giffgaff deals include a 5GB EU roaming allowance.

Smarty - has a straightforward, effective offering of Sim-only deals at cheap prices. It doesn’t sell phones or offer fixed-term contracts. The success of this is shown by its sixth consecutive year as a WRP and a third year in a row as a Great Value network. It’s an exclusive group, as only two other providers received both endorsements this year. Smarty provides a decent 12GB of free EU roaming. 

1p Mobile - after first entering our results in 2024, landing mid-table, then last year being recognised with our Great Value endorsement, 1p Mobile improves again. It attains both WRP and Great Value status. 1p Mobile offers a unique pay-as-you-go tariff where 1MB of data, a call minute or a text costs 1p each. Alternatively, it offers rolling monthly Sim-only deals with a bundle of data, calls and texts.

Lebara - perfect for frequent travellers or anyone with relatives living abroad, Sim-only deals with Lebara offer a generous 30GB of free EU roaming and either 100 or 500 minutes of international calls. It’s a strong all-round performer and receives WRP status for a fourth year in a row. Although it didn’t quite meet our criteria to also be Great Value, customers nonetheless rated it five stars for value for money. 

Use our mobile network coverage map to see which providers have the best signal in your area.

Mobile networks that offer great value

Two networks didn't quite make the grade as Which? Recommended Providers, but we've recognised them as Great Value options that offer a good amount of data at excellent prices.

Asda Mobile - despite an impressive customer score and no star ratings lower than three, Asda just missed the cut to be a WRP. However, its Sim-only deals are affordable and worthy of being a Great Value network for the third consecutive year, which make it an attractive option. This is reflected in a four star rating for value for money. All contracts include 5GB of free EU roaming.

iD Mobile - incredible value is the core of iD Mobile’s offering, with huge amounts of data available cheaply and a 30GB EU roaming allowance included in all contracts. The network has been rated Great Value every year since we launched the endorsement in 2023, but similarly to Asda, doesn’t quite make it to WRP this year. This is reflected in its rating, as customers gave it four stars for value for money but two stars in all other categories. 

How to switch and save

Smaller providers often offer significantly better value. Survey respondents using one of the big four networks paid an average of £16 for a SIM-only contract, compared with just £9 on smaller networks. For contracts that include a phone, the average cost was £40 with the big Four, versus £28 with smaller providers.

Switching to a rolling monthly contract with a smaller provider is the best way to cut your bills and avoid price increases, plus you can take advantage of better, newer deals as they emerge. If the provider raises prices, you can switch to a different network at the end of the month. 

Alternatively, look for a 12, 18 or 24 month Sim-only contract with a fixed price guarantee from a Which? Recommended Provider or Great Value network. 

We spoke to Jackie Gallego, Which? Home Editor, about how making 10 minutes of effort to switch networks saved her hundreds of pounds every year. Jackie said:

‘After a stern talking-to by Which? tech editor Paul Lester, I was finally convinced to ditch my O2 Sim-only mobile phone contract in November 2025. I’d signed up in 2018, lured by the promise of priority gig ticket booking through the O2 rewards app. It sounds like I was a truly loyal customer, but really, the painful process of switching back then left me unwilling to face it again in a hurry. Over the years, my bill slowly crept up from £17-ish a month to around £27, plus extras. One price bump was because I needed additional data, but the others were seemingly routine increases. 

'My new Sim-only deal with Smarty costs me just £8 a month for a chunky 50GB of data (an excellent Which? member offer), and it took me just 10 minutes to arrange. All I had to do was sign up on the Smarty website and request a porting authorisation code (PAC) from O2 so I could keep my old number. Number porting takes one working day during the week, so I made sure to get my request in well before the weekend. Smarty did all the rest. My Sim duly arrived in the post, I popped it in and I was good to go. The whole process was really easy and will save me at least £200 a year. My only regret is leaving it so long.’

For more information on switching, such as how to switch if you're in a contract, and how to choose a provider with the best signal, read our full guide on how to switch mobile provider. Then use our mobile comparison service to find a cheap deal to switch to.

Which? encourages customers to make the most of better, cheaper options

Our research clearly shows that while some networks are impressing customers, plenty continue to underperform. Customers should explore different options and expect better value and service from their network.

Natalie Hitchins, Which? Home Products and Services Editor, said: 'Our latest research shows that smaller providers are consistently outshining the industry’s largest mobile firms by offering better customer service and far cheaper deals - with some customers missing out on savings of up to £200.

'Notably, many top-rated challengers avoid mid-contract price hikes, offering households much-needed certainty amid rising essential costs.

'Any customers nearing the end of their contract who are unhappy with their service, or simply looking to save money, should not hesitate to vote with their feet and move to a provider that actually delivers on value.'