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O2 review 2024: still the UK's slowest mobile network?

O2 Mobile reviewVisit O2.co.uk

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We joined O2 on a SIM only plan, to see if you should too. This is our experience of their 5G/4G coverage, speeds and other network benefits. Last updated: 8th June 2023.

Overall rating

SIM Sherpa rates O2 as a very good network to be on
(3.5/5, very good)

"For having signal to make calls and sends texts, no one beats O2. But their data coverage is beatable and their 4G speeds are a bit of a let down for advanced users. Their 5G is temperamental too.

They’ve got all the extra network features a main network must have, like 4G calling, WiFi calling and one of our favourite free hotspot schemes. O2 are a very safe pair of hands network-wise.

O2 have done well to keep EU roaming inclusive on every plan and even offer some worldwide locations on selected ones. Their customer service has an excellent record too.

If you’re someone who wouldn’t describe themselves as an expert and just wants a service that works reliably, without being the fastest and flashiest, we think you’ll be very happy on O2."

The 3 best bits

1) Last major network to keep EU roaming
2) Excellent mix of coverage
3) Decent phone contracts

The 3 worst bits

1) Slowest 4G speeds on average
2) Tough phone contract credit requirements
3) No recent innovative extra benefits

Is O2 owned by BT?

No. O2 was long owned by the Spanish operator Telefonica but they have recently just been bought by Virgin Media.

Can I move my number to O2?

Yes. Text PAC to your old provider on your old SIM to the number 65075 and give O2 the code. They’ll transfer your number over within a working day.

Why is O2’s 4G so slow?

We think a lot of the reason O2 are slower for 4G than others is how they’ve implemented the technology. They don’t have as many frequency bands working together. And they’ve likely achieved bigger 4G coverage with longer range transmitters, at the expense of speed.

Information symbol We're a professional reviews website but we bought our O2 SIM card as a regular consumer, to test what it's actually like for real life paying customers. The contents of this review are a combination of our expert industry knowledge and what we experienced during our test.

Is O2's network any good?

Coverage is strong point for O2, especially for calls

Check O2 4G/3G signal

Check coverage in your areaSee coverage map

at O2.co.uk
(opens in new window)

O2 are one of the four main UK networks, meaning they own the network they use to provide signal rather than depending on any other network (but they are now owned by Virgin Media).

Out of all networks, we’d say it’s O2 that has the best coverage for calls indoors and out. They’ve got the largest amount of the UK’s geographical landmass covered and use decent frequencies for indoor coverage.

Their 4G data signal (see 5G here) isn’t the most widespread of all networks as they’re a bit behind EE and Vodafone. Our real life tests had us bumped down to 3G on O2 more often than those, but this wasn’t an issue in cities.

We took our O2 SIM to different areas to see how good their coverage is for ourselves. We tested in built-up, suburban and more rural areas. We were on 4G basically all the time in built-up areas.

You’ll sometimes be left wandering the house trying to get signal on other networks, but we were able to get call signal and 4G signal all throughout the house.

It’s inevitable that signal will suffer in some places. That’s why it’s helpful to use O2’s signal map to see if they or the providers on their network are right for you. We found their map pretty close to reality.

It’s worth using O2’s coverage map here to see what signal will look like in your area. We imagine most people throughout the country will be happy with them, but it’s good to be sure before joining them.

Useful link: Other networks that use O2

Our coverage rating:
★★★★☆ (excellent)

Joint 2nd

Not as good as:

Better than:

4G data speeds can be underwhelming on O2

O2's 4G banner

Speeds are typically sluggishWhat O2 say

at O2.co.uk
(opens in new window)

While O2 are good at providing 4G signal in lots of areas, we’ve found the actual speeds you get over 4G can tend to be a bit disappointing. That lines up with what the independent network testers say:

Opensignal take millions of measurements on real people’s phones and have shown typical 4G downloads at 16.8 Mbps on O2. That’s the slowest of all networks by a noticeable distance.

We wanted to see what speeds on O2 will look like in real life and how they compare to the results from Opensignal. We found that their results line up well with our tests.

Our speeds went down to around 6 - 7 Mbps in smaller towns and down to 5 Mbps in rural areas. However we did manage to get up to 95 Mbps in the city centre. But for the most part we got around 15 - 20 Mbps.

You won’t notice a massive difference in speeds when browsing the internet compared to other networks, but tethering to large screen devices will be noticeably slower when loading pages or videos.

Typically their speeds are around what you’d get from non-fibre home broadband. Streaming HD video should be decently smooth, but you’ll notice their slower speeds when doing things like file sharing or gaming.

You can get much faster and much slower speeds than that, depending on where you use your phone. Their typical speeds are what you’d get from old copper home broadband, so you might notice buffering on videos.

Before choosing whether or not to join O2, you should consider whether this is something that you care about. For basic social media, maps and browsing you probably won’t mind. Demanding users should think twice.

Useful link: You can test and return your SIM if you're not happy

Our speed rating:
★★☆☆☆ (average)

Joint last (with other networks who use O2)

Not as good as:
EE, Vodafone (4G), Three

Better than:
Vodafone (5G)

5G coverage is great but speeds lag behind other networks

O2's network map

Lots of 5G live locationsCheck near you

at O2.co.uk
(opens in new window)

As coverage improves and more people have 5G-ready phones, 5G data is becoming more important, as you’ll start to spend more time on it. We’d say 5G is a mixed bag on O2.

They have 5G live in 750+ UK towns and cities, which is more than any other UK network. And in our research for our best 5G networks list we found they were great at covering their locations.

You get 5G included on every O2 SIM only deal. Here are their best ones right now:

But again, O2 are held back by their middling speeds. Independent testers Speedtest and Opensignal put typical speeds on O2 between 80.57 - 92.3 Mbps with peak speeds up to 214.2 Mbps.

That’s not to say O2’s 5G is slow. It’s a massive and welcome step change from their 4G data. But if you’re after bragging rights, or you’re doing demanding stuff on your mobile you might prefer Three or EE.

Useful link: How is O2’s 5G rollout going?

Our 5G rating:
★★★☆☆ (great)


Not as good as:
EE, Three, Vodafone

Better than:

WiFi/4G calling on O2 is good enough for most users

O2's WiFi calling and app

Check your phone model is compatibleSee supported phones

at O2.co.uk
(opens in new window)

While O2 are typically good at getting call signal into buildings, you might still struggle to get signal indoors if there’s obstructions between you and the nearest mast. This is where WiFi/4G calling comes in handy.

WiFi calling allows you to make/take calls over WiFi signal where call signal is poor. 4G calling does the same thing with 4G signal. And you can also send/receive texts over WiFi and 4G too (read our guide here).

We tested both features using a manufacturer-bought Android phone and an iPhone we bought from a different network. We got WiFi calling and 4G calling to work on both, but we had to turn it on in our account first.

While other networks show a special symbol to let you know you’re calling over 4G, O2 don’t seem to have this. But that doesn’t mean it’s not working, so don’t panic.

WiFi calling will only “kick in” when you’re somewhere with very weak call signal, but it should work on its own. In our testing we struggled to get somewhere with weak enough call signal to get it working, however.

Calls over WiFi connected at the same speed as on conventional call signal and the call quality was good. And we switched from a WiFi call to a 4G call without it dropping (it will drop if you lose 4G signal).

If you take a phone from O2 directly it should be compatible for WiFi calling. The issues come when trying to get devices bought elsewhere to work with O2’s WiFi calling (see if yours is compatible here).

Most iPhone devices should work for WiFi calling, but O2 don’t say for certain if Android models not bought for them are compatible. But in our tests our manufacturer-bought Android model worked just fine.

Useful link: How to set up WiFi calling on O2

Our WiFi calling rating:
★★★☆☆ (good)


Not as good as:
Three, BT, EE, iD

WiFi hotspots are the best of O2’s extra network features

Free O2 WiFi hotspots

Automatically connect to 7000 hotspotsHow you get it

at O2.co.uk
(opens in new window)

It’s good to know what extra network features O2 offer before joining them, so you can know what you’re getting out of your deal and whether they’re the right network for you:

O2 help you save data on the go with their network of 15,000+ WiFi hotspots around the UK and on the Underground. And you can automatically connect to 7000 of these, though you have to log in manually for the rest.

You can use your phone as a personal hotspot to tether other devices to your data signal with no limits on every O2 plan. You can do this even while you’re abroad too.

O2 also offer call forwarding, letting you keep one line free from incoming calls by automatically forwarding them to a different number. But this isn’t offered on Pay As You Go.

You can customise your voicemail however you want and are one of the few networks to include visual voicemail. If your phone supports it, this lets you sort through each of your voicemails one by one.

Finally, you can get an eSIM on O2 as well. However you have to wait for your SIM package to arrive to scan the QR code to get it working. But if you don’t mind waiting a couple of days this shouldn’t be an issue.

Useful link: How to get an eSIM on O2

Our free WiFi rating:
★★★☆☆ (good)


Not as good as:
BT Mobile, Virgin Mobile

Slightly better than:
Everyone else

O2's perks and extras reviewed

Inclusive EU roaming on all plans is a great benefit

Free EU roaming on O2

Inclusive EU roaming on all plansCheck countries

at O2.co.uk
(opens in new window)

The other UK networks (EE, Three and Vodafone) have all removed inclusive EU roaming from their plans, while O2 have kept theirs in place. This means you can use your O2 SIM in the EU at no added cost.

You can roam in these 48 EU/EEA destinations on every O2 deal. While there you are limited to 25GB of your data allowance, unless you’re on a smaller plan than that in which case you can use your whole allowance.

And you can get their Travel Inclusive Zone benefit on O2’s premium plans. With this you can roam in these 27 non-EU countries with an allowance of 120 mins, 120 texts and a bit of data (probably 150MB) each day.

These offers let you roam in 75 destinations at no extra cost:

On top of that, once you’ve used up that small allowance you actually get unlimited data to use in their Travel Inclusive Zone, but it will be severely speed capped. And, again, this is only on their priciest plans.

O2 are better than their rival networks for EU roaming while also having a nice worldwide roaming scheme on top of that (Vodafone’s may be better for some). That’s why they’re our favourite overall roaming network.

Useful links: The best networks for going to the EU and beyond

Our roaming rating:
★★★★☆ (excellent)


Not as good as:
Vodafone (beyond the EU)

Slightly better than:
All others

O2’s Priority rewards app is still a very popular benefit

O2 Priority rewards scheme

Money off shopping, dining and moreWhat you get

at O2.co.uk
(opens in new window)

Every customer benefits from O2’s popular Priority reward scheme, whether on pay monthly or Pay As You Go. This gives you extra rewards for staying loyal to O2.

These include discounts on high-street food, drink and entertainment which you can use online or in store. A few of these are entirely exclusive to the O2 Priority app, but not all of them.

And O2 can get you presale access to some music and sporting events hosted at O2-sponsored venues or by O2 themselves (see what you can get here). They call it O2 Priority.

It’s the best loyalty rewards scheme of them all, with Vodafone’s VeryMe as a close second. It helps you get better value out of your deal, which is nice considering the high cost of O2’s plans.

Useful link: O2 Priority help guide and FAQs

Our rewards rating:
★★★★★ (best choice)


Better than:
Vodafone / VOXI

Way better than:
Everyone else

O2’s Extras give you a nice bit of extra value on your plan

O2 Extras banner

Higher end plans give you more benefitsSee the choices

at O2.co.uk
(opens in new window)

The main UK networks tend to offer pricier deals than the smaller providers on their networks. As such, O2 try to add as much value to their plans as possible by offering free entertainment trials on their plans.

You can also get a free trial to an entertainment service or app of your choice from the ones listed here on certain O2 SIM only and phone contracts. Usually the more your plan costs the longer your trial.

Here are the current best SIM only deals that include Extras:

These services include Disney+, Amazon Prime Video, Music Unlimited and Audible. There are a couple other choices too. These trials only last between 3-6 months after which you’ll begin paying for it.

Once the free trials are over you’ll have to cancel them manually or else you’ll start being charged. These are great for getting extra value out of your plan, but are only worth it if you actually want them.

Useful link: The full terms and conditions of O2’s Extras

Our freebies rating:
★★☆☆☆ (average)

Joint last

Not as good as:
EE, BT Mobile, Vodafone

Better than:
All others

Families will love O2’s Multisave discount scheme

O2's Family Plans

Money off added deals on your accountFamily Plan discounts

at O2.co.uk
(opens in new window)

Networks want to encourage customers to add extra users to their account, so a few of them offer family plan schemes to give them more of a reason to do so. These come in the form of extra benefits and discounts.

O2 offer a handy 20% discount on extra SIM only or usage (the SIM plan for your phone contract) plans added to your existing O2 account.

You should know that you only get a discount on the usage plan (mins, texts and data) of any phone contract you add to your account, not a discount to the actual cost of the device.

O2 used to offer Sharer plans that let you transfer data from one user on your account to another, but you can’t get these anymore. Overall, O2 offer a nice family plan that helps make up for their higher prices.

Useful link: Calculate Family Plan discounts

Our Family Plan rating:
★★☆☆☆ (average)


Better than:
All others

Data rollover is a nice extra feature on O2’s PAYG bundles

O2 data rollover on pay as you go

More time to use the data you paid forSee PAYG SIMs

at O2.co.uk
(opens in new window)

You’ll basically never use the exact same amount of data each month. You may end up using all your data one month then use hardly any the next. Some providers let you keep your unused data to help with this.

This is called data rollover and O2 are one of the networks that offer it (read our guide here). But they only include it on their Pay As You Go “Big Bundles”, not their regular pay monthly contracts.

O2 let you hold onto your unused data for a few months after your plan expires. There is a cap on how much data you can roll over, which tends to be the amount of data you get with your bundle.

Just make sure to renew your bundle every month or else you’ll lose your rolled over data. It’s a great scheme overall, we just wish it applied to their pay monthly contracts as well.

Useful link: O2’s terms and conditions for their Big Bundles

Our data rollover rating:
★★☆☆☆ (average)

Joint 5th

Equal to:
EE and Vodafone

Other nice benefits of being on O2

Spending cap amount selection screenshot

Set spending caps at these incrementsRead O2's guide

at O2.co.uk
(opens in new window)

You will miss out on some of the extra benefits you’d get on other networks on O2, but before we go over those we’ll take you through the other small benefits of joining O2:

They let you set a limit on extra spending. Their caps are more flexible than some networks, but not as flexible as others that let you cap in £1 increments. And every network has to let you set a cap anyway.

O2 automatically block adult content over data signal, meaning you can be sure your kids are safe online. You will have to set separate content restrictions for your home WiFi, however.

And there are a few key benefits that O2 users miss out on. We’ll go over them in the next section.

Useful link: Our guide to the most flexible spending caps

Our spend cap rating:
★★★★☆ (excellent)


Not as good as:

Equal to:

What other networks do better than O2…

Sky Mobile unlimited streaming

Unlimited streaming data on SkyHow it works

at Sky.com
(opens in new window)

You don’t get unlimited streaming data on O2. This is something that Sky (who use O2’s network) offer for use with their TV apps, so TV customers watch their favourite shows on the go without using up their data.

And O2 don’t let you switch plans up or down during your contract (but they do let you do this on their phone contracts). giffgaff piggyback off O2 for signal and let you switch plans each month however you like.

Extra data add-ons are expensive on O2 (1GB for £12!) so you’ll have to make sure not to go over your allowance. And international calls can also add up quickly, even with their “International Bolt-on”.

O2 will also up the cost of your SIM only or usage plan every year. Last year O2 customers saw a rise of 11.7% on what are already pricey plans. At least the cost of your device won’t go up on O2.

And you don’t get data rollover on their pay monthly deals. Sky Mobile have the best scheme of all networks, letting you store unused data in a piggybank for up to 3 years and withdraw it when you need.

Useful link: All providers on O2’s network

Comparing O2's deals

Different deal types available on O2

Choose which type you're looking for to learn more:

Special offers currently on O2

What promotions are the on O2 this month?

SIM only contracts on O2

Compare prices on pay monthly SIMs on O2 with our handy tool just below

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Phone contracts on O2

We go over the pros and cons of O2’s phone contracts:

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O2’s Custom Plans offer a nice bit of flexibility

O2's customisable plans

How custom plans work

at O2.co.uk
(opens in new window)

O2 let you choose the length of your phone contract anywhere between 3 and 36 months over which you’ll pay off your phone. And you can choose how much you want to pay upfront and take a data plan that suits you.

The longer your contract length the less you pay per month. By choosing your contract length you can suit your plan to your budget depending on how much you wish to pay per month and how long you want to be paying.

This flexibility does make it harder to know what is the best possible deal you can get. However, O2 keep the cost of your device the same no matter how you set up your contract.

Some providers make you pay extra for a longer contract. While technically you’ll pay more on a longer contract by continuing to pay for your usage plan, the overall cost of your device stays the same on O2.

We’d still say it’s better to take the shortest contract you can to suit your budget, as once your contract is over you can change to a SIM plan on a cheaper provider.

Useful link: How building your own plan works

O2’s Refresh contracts are a nice way to upgrade early

Early upgrade with O2 Refresh

About early upgrades

at O2.co.uk
(opens in new window)

O2 split the cost of your phone and usage plan (mins, texts and data) into separate payments which combine together to make your monthly bill.

O2 call these deals Refresh and they’re basically credit agreements for the cost of your device that you pay back over your contract. Sky Mobile, Virgin, giffgaff and Tesco all offer similar kinds of deals.

So you can upgrade early without having to wait for your contract to end if you can afford to pay off your remaining loan. Once you’ve done that then you’ll only have to pay for your SIM plan.

The main issue is that these phone contracts are basically loans worth a lot of money. That means it can be tougher to pass a credit check for one of these contracts than on some other networks.

Useful link: O2's full guide to their Refresh tariffs

O2's Pay As You Go

What options do you get to pay as you go on O2?

O2’s PAYG bundles offer nice benefits at higher costs

Expired stampO2's classic pay as you go plan

See bundles

at O2.co.uk
(opens in new window)

We went over O2’s “Big Bundles” above. These are bundles of mins, texts and data that you pay for every month. You no longer to Pay As You Go by topping up with credit and paying out of that.

The only provider on O2’s network that still offer a traditional Pay As You Go system are giffgaff. Here are their rates:

Or you can join 1pMobile who provide signal via EE’s network and have the cheapest tariffs of all UK providers:

O2’s bundles are higher cost than O2’s SIM only contracts. But you don’t have to pass a credit check and you’re not stuck on a contract. But you might just be better off joining Tesco or giffgaff on a pre-paid deal:

O2 customer service reviews

O2’s customer service record has got worse

Ofcom complaints data table

3 complaints per 100,000 customersSee all O2's awards

at O2.co.uk
(opens in new window)

It’s inevitable that users will have to get in contact with a network to resolve any issues they might be having. If a network fails to solve their customers’ issues, the customer still has options.

If a network is unable to resolve a customers’ issue online then that customer can make a complaint to government regulators Ofcom. Their record shows how many complaints they got about each network.

We ran into issues getting our O2 SIM to connect to 4G as it seemed to be stuck on 3G. We used this as an opportunity to contact O2’s customer service and gauge how helpful they were.

Their call agents were UK based and politely and professionally helped us in getting our issue resolved.

Our issue took a number of days to get fixed, but the customer service people were very apologetic and offered financial compensation for the wasted days without 4G.

In our experience we’ve found that O2 are good at getting their customers’ issues resolved, but they are a huge network under new ownership, so their complaint record could start changing.

O2 now sit at 3 complaints per 100,000 customers, which is more than the industry average. While that doesn’t sound good, the industry average itself has been falling too, so networks overall are getting better.

If you’ve run into issues with other providers, then you’ll find that O2 are better than some. While this blip on their record might be a bit of a worry, we think most users will still be happy with O2’s customer service.

Useful link: How to get help on O2

More O2 guides

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