O2 mobile review

O2 is one of the Big Four mobile providers and offers a range of Sim deals. How did its customers rate it?

Before signing up for a new phone deal, read our review of O2 to see how it did in our customer satisfaction survey of mobile network providers.

Discover which mobile network providers impressed their customers most in our latest survey, which reveals the best and worst mobile networks. 

Is O2 mobile any good?

• 'Bit expensive and no incentive to stay as a customer.'
• 'My experience has been mixed. The network generally works well and coverage is acceptable, but issues with customer service, billing and technical support prevent me from feeling fully satisfied.'

O2 mobile review

Customer score: 67% (14th out of 15). Which? members can also read our full review, including how its customers rated it for key factors, such as customer service and network reliability.

If you're already a member, log in now, or join Which? today.

Browse all O2 Sim-only deals, or check our expert picks of the best Sim-only deals. 

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How good is O2 mobile coverage?

O2 has its own network and offers 2G, 4G and 5G coverage.

You can check the network quality where you live by using our mobile network coverage checker. Enter your postcode into a map, and it will tell you how good the O2 signal is in your area, and compare it with the other providers.

O2 Sim-only deals

View a selection of O2 deals below and click 'Show More' to browse.

O2 deals and incentives

O2 is also known for offering perks, including O2 Priority. This gives customers access to a range of offers, including pre-sale tickets. The O2 Rewards scheme for PAYG customers gives you back up to 10% of your quarterly spending on credit.

Compare the best O2 Sim-only deals and see how much you could save.

Does O2 increase its prices each year?

Yes. Previously, O2 increased its prices using the Retail Price Index (RPI) rate of inflation, plus 3.9%. Following campaigning from Which?, this type of unpredictable, inflation-based increase was banned, and providers must state rises in pounds and pence. 

In November 2024, O2 announced that its new price rise for all new, re-contracting and existing customers would be £1.80 extra per month. The first increase of this type arrived in in April 2025. It has subsequently stated that prices will now increase by £2.50 per month for new and existing customers.

To find out how to avoid costly price increases, read our guide to 10 ways to save money on your mobile phone bill.

Does O2 mobile include free data roaming?

Yes, all O2 Sim plans come with 25GB of free EU roaming. 

However, always check to see if the country you’re travelling to is covered before you leave. Some countries you might expect to be included, may not be.

It may be cheaper to buy a travel eSim for your trip, rather than relying on data add-ons or PAYG. Find out how to do this and what’s available in our guide to the best cheap eSims for mobile roaming abroad.

For more details and tips for roaming, read how to save money on mobile roaming charges.

O2 stores

O2 is one of the UK's biggest mobile phone providers and has hundreds of high street stores, many of which offer technical support from the company's 'O2 Gurus'.

You can find your nearest branch using the O2 store locator or by calling O2 customer service on 202 (from an O2 mobile) or 03448 090202.

Find out how other providers fared in our guide to the best and worst mobile networks.

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 swayed by third parties, and we don't accept freebies from product manufacturers or retailers.

We buy all the products that we test ourselves, so our advice helps you to make the right choice first time and avoid a costly mistake.