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O2 mobile real-life review: how we found their network in tests

O2 Mobile reviewVisit

The retailers featured on this page may compensate us when our readers follow links to their websites and make a purchase. More

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. SIM Sherpa is your trusty guide. Last updated: 28th January 2021.

Overall rating

SIM Sherpa rates O2 as a good network to be on
 (3/5, good)

"There’s no doubting the quality of O2’s network coverage, particularly indoors and for calls. They’ve got the extra connectivity features that are a must for a main network too: WiFi calling, VoLTE and free hotspots.

We do find O2’s 4G data speeds are a continual let-down though and their 5G is temperamental if you’re not right by where the transmitter is located. They’re a little light on novel perks and benefits too for the money.

Their customer service is very good though and O2 are always among the least-complained-about networks. And we know their subscribers are fiercely loyal once they’ve joined, maybe thanks to schemes like Priority.

Overall, O2 suits a certain type of customer: someone who’s after the re-assurance of joining a big name and isn’t fussed about having the fastest data or whizziest features but just wants a safe pair of hands. That's O2."

The 3 best bits

1) Excellent coverage in the UK
2) Ultra-flexible phone contracts
3) Best perks scheme O2 Priority

The 3 worst bits

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

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?

O2's coverage is their strongest asset - particularly calls

Check O2 4G/3G signal

Don't just search at home, try multiple placesSee coverage map

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O2 are one the four UK providers that own and operate their network. And they're descended from some of the UK's original mobile networks, meaning they've had decades to get coverage right.

And for basic calls and texts, we think practically everyone will be happy. O2 have the joint-largest coverage for this. Wfound you have to be somewhere geographically odd to lose signal, like in a dip or behind a hill.

Added to that, we find O2's indoor signal for calls excellent. Some providers can find it tough getting their reception through building materials. O2's signal for calls/texts is on better frequencies for this.

We took our O2 SIM out and about in cities, towns, villages and countryside. And it's genuinely pretty hard to get away from O2's signal. In built-up areas, we were rarely without 4G.

We're particularly impressed with O2's indoor coverage. We found you didn't have to do the classic going to window to make a call that you can find on some networks. Both 4G and 3G/2G were capable of getting in.

Coverage will always vary upon location. What's good near us, won't necessarily be the same near you. Use O2's map - we found it's accurate and doesn't really exaggerate reception.

For 4G data reception (see 5G below), if you're in built up areas, you're rarely without 4G on O2. Small towns and villages, you are slightly liable to drop down to 3G more than on EE or Vodafone. Big cities are no problem.

Useful link: Check O2 coverage where you use your phone

The 5G rollout on O2 is going alright too

5G's on a street-by-street basisCheck near you

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All O2's SIM only plans are sold as 5G-ready (make sure you select that your device is 5G-ready in the checkout to get a 5G SIM) and you'll get 5G with any phone contract if the model supports it.

And their rollout looks good on paper. They've now got 5G in 150+ locations up and down the UK. But within those places, the coverage is still very much on a street-by-street basis (see here).

Our own testing with an O2 SIM card has found that the predicted coverage is accurate but if you're away from the transmitter, the 5G quickly becomes less useful than 4G in the same area for speed!

So O2, like all networks, are a long way from universal 5G coverage. And realistically, you'll still spend most your time on 4G when you're out and about.

Useful link: O2 5G rollout latest locations and news

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

Joint 2nd

Not as good as:

Better than:

Data speeds on O2 are still a bit of a weakness

O2's 4G banner

Good coverage, average speedsWhat O2 say

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We try out a lot of mobile networks and we have to say that O2 and the providers that use them are noticeably slower than their big rivals EE and Vodafone (read O2 vs EE here and O2 vs Vodafone here).

Independent network testers Opensignal and Speedtest by Ookla that use millions of speed measurements have long put O2 bottom for average downloads - with customers typically receiving 16.95 - 18.00 Mbps.

We did some spot tests of O2's download speeds to double-check the independent speed testers' results. We found them to be very believable.

Often in small towns, 4G was as slow as 6 or 7 Mbps. And we found it hard to get 4G faster than mid-30 Mbps in more urban places. More often we were looking at 15 - 20 Mbps.

For basic browsing, there mostly wasn't a hugely noticeable difference. Although tethering a laptop to do work tasks on O2 meant waiting a second or two longer to load pages.

That's similar to top-end non-fibre home broadband, so it's not dreadful. You can still watch videos at those kind of speeds. But things like group video calls or gaming isn't going to be silky smooth.

5G will make a difference once it's more universal. But for the time being, it's worth knowing O2 are the slowest network. If you're a basic user thatjust wants to check the news, social media and emails, you'll be fine though.

Useful link: What O2 say about their own 4G

Our speed rating:
★★☆☆☆ (average)

Joint last (with other networks who use O2)

Not as good as:
EE, Vodafone, Three

Better than:

O2's WiFi calling and 4G calling are decent

O2's WiFi calling and app

O2 will need to support your particular phoneSee supported phones

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O2 are already one of the better networks for indoor coverage to make phone calls. But just in case, they also offer WiFi calling / 4G calling on all their pay monthly plans.

O2's WiFi calling lets you make and take calls via WiFi, in the same way you would over their conventional network. Although it doesn't support SMS text messages yet like some providers' (read our full guide here).

We tested both services in manufacturer-bought Androids and an iPhone from another network. O2's WiFi calling and 4G calling worked on them all. But we did have to turn it on manually in our O2 account.

Unlike other networks, you don't get a special 4G calling icon when you're making a 4G calling call on O2. It just doesn't flip to 2G/3G when you start the call like providers without the feature.

It can be difficult to get WiFi calling to "kick in" if you're somewhere where there's plenty of mobile signal. If you're down to a bar or two, it does turn on automatically.

Calls over WiFi connected at a similar speed to normal, the audio quality was good. And we successfully moved away from WiFi mid-call, without the call dropping (transfer to 4G call).

If you're joining O2 on a phone contract and the model has WiFi calling, the feature should always work. If it's on SIM only with a phone from elsewhere, there could be some support issues (see latest device list here).

iPhone models should work. But O2 are still reserved about saying they'll definitely support Androids, even if the phone has the feature. Our own tests found it did work on non-O2 phones. But we can't guarantee it either.

Useful link: All about how O2's WiFi calling works

Our WiFi calling rating:
★★★☆☆ (good)


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

Free WiFi hotspots: O2 are among our best-rated providers

Free O2 WiFi hotspots

Free, fast and unlimited WiFi data on O2How you get it

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In our reviews, we're always on the lookout for networks that help you save your monthly allowance of mobile data by offering you free access to public WiFi hotspots to use instead.

This is an area we can give O2 a good rating for because all their customers (pay monthly or pay as you go) get free access to their network of approximately 15000 WiFi hotspots nationwide (find ones near you here).

We took our O2 SIM out and about to get some free WiFi and test whether O2's WiFi Extra automatic login function truly works.

We were pleasantly surprised to see the hotspot automatically recognise our O2 SIM. We didn't have to select the hotspot from the phone's WiFi menu, nor was there any login process.

The phone just silently flipped to WiFi, just like it would between 3G and 4G when moved around. Impressively slick.

The WiFi itself is nothing to write home about. The speeds are enough to do the basics but you wouldn't sit there watching videos or downloading massive files in a hurry.

But as a way of staying online if you're out of data or signal, it's a nice little extra to have.

Their free WiFi tends to be located in useful locations on the high street like restaurants, cafes, shopping malls. It is free whether you're on O2 or not but there is an extra benefit if you are an O2 customer:

At about half the locations, the hotspot will automatically recognise you as an O2 customer and connect your phone without having to login manually.

All in all, O2 WiFi is a nice free benefit that saves data and gives you a fast internet connection.

Useful link: All about free O2 WiFi from their official guide.

Our free WiFi rating:
★★★☆☆ (good)


Better than:
Everyone else

Tethering: it's allowed on all O2's deals

O2 tethering policy

Tethering could quickly push you over data limitsSee extra data costs

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Tethering is using your phone and its mobile data connection to create a mini WiFi hotspot around you that you can connect other internet-enabled devices to when you're away from home.

Not every network allows you to do it because it can use up data more quickly than just regular browsing on your phone (check O2 costs for going over your limits here).

Tethering is allowed on O2 whether you're on a pay monthly or pay as you go phone or SIM only plan.

For that reason, we can give O2 our joint best choice rating for tethering.

Useful link: Read general O2 terms and conditions

Our tethering rating:
★★★★★ (Joint best choice)

Joint 1st

As good as:
EE, Vodafone, O2, BT, Plusnet, Tesco

Better than:
iD Mobile, Virgin Mobile

O2's perks and extras reviewed

O2's Priority reward scheme has been popular for years

O2 Priority rewards scheme

Offers and exclusive experiencesWhat you get

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We'd say the most popular benefit you get on O2 is access to their Priority reward scheme, which every customer can utilise - no matter whether you pay as you go or pay monthly, have a phone or a SIM.

It's essentially a collection of special offers online, on the high street for food, drink and shopping - many of which are exclusive to the scheme (although plenty are matched by similar voucher sites).

If you're into live music or sports, the more interesting bit is probably the first access to ticketing for events that you get on O2 Priority at venues that the network sponsor (see the sorts of thing here).

Priority is the best such scheme on a mobile network (Vodafone have something similar) and if you're willing to spend time seeking out the best offers, it's a decent way to claw back some of the cost of your mobile deal.

Useful link: O2 Priority help guide and FAQs

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


Better than:
Vodafone / VOXI

Way better than:
Everyone else

O2 Extras add a bit more value to their top-end plans

O2 Extras banner

Choose a free trial with premium plansSee the choices

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Main networks like O2 need to find ways to justify their higher prices than smaller providers. Vodafone, EE and O2 now all have schemes where they give you some kind of inclusive entertainment subscription.

Take the right phone contract or pay monthly SIM only plan and O2 will throw in a time-limited free trial to your choice of one of the apps / services listed here. Of course, the "selected plans" are the more-premium ones.

These are our best-rated O2 plans that include an Extra for at least 3 months:

The list includes trials to services people will like such as Disney+, Amazon Music Unlimited, Prime Video or Audible. And a few others too. But your choice is only free for 6-12 months, after which the service is payable.

So really it's one of those offers where O2 are giving with one hand and taking with the other. That said, if the plan you want includes it anyway and you cancel after the trial or are happy paying, it's no bad thing.

Useful link: Full O2 Extras terms and conditions

Our freebies rating:
★★☆☆☆ (average)

Joint last

Not as good as:
EE, BT Mobile, Vodafone

Better than:
All others

Inclusive roaming: some O2 plans cover non-EU destinations

Free EU roaming on O2

48 free roaming destinations in the EUCheck included countries

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Like every UK mobile network, roaming in the EU costs the same on O2 as it would at home. If you pay monthly, you'll pay no extra to use your allowance. On pay as you go, you'll pay the same rates there.

Quite a few of O2's more-premium phone plans and SIM only contracts, now also include something called O2 Travel, stretching to these extra 27 non-EU destinations like the USA.

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

With these plans, you'll get a daily allowance of 120 minutes and texts back to the UK. Plus 100MB data at full speeds, after which it's throttled to lower speeds - that'll cover things like Google Maps and a bit of browsing.

It's definitely a bonus, it's just not as generous as Three's Go Roam scheme or Vodafone's Global Roaming. See all other roaming costs on O2 here.

Useful links: Guide to the best networks for roaming

Our roaming rating:
★★★☆☆ (good)


Not as good as:
Three, Vodafone

Slightly better than:
All others

Spending caps: you can now limit overspending on O2

Spending cap amount selection screenshot

Choose a set amount or no cap at allRead O2's guide

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In this category, we look at what measures each provider has to stop you racking larger-than-expected bills for going over allowances or using other premium services (every network must do this now by law).

O2 have recently introduced the ability to set a cap on how much extra you're willing to spend above and beyond the usual cost of your plan (here's their full guide to how it works).

If you hit the limit, any services that would result in more charges to your bill will be temporarily blocked until the next month or until you change your cap. Everything else carries on working as usual.

Even though it's easy to set up a spending cap while you're ordering from O2. It's a huge pain in the neck if you ever want to change it. You can't just do it in your online account or via the app.

Instead you have to get in touch with their online chat service or phone them free from your SIM. Either way, it's time-consuming, when other networks let you quickly change it in your app.

O2 keep you informed via text when you're getting near your limit and when you've hit your spending cap, which is good:

Screenshot of texts from O2

Overall, we'd say the functionality of the cap itself is good. It's just irritating to manage your cap.

You can choose a limit between £0 and £200, or none at all. And you can change your choice once a day, so O2 are extremely flexible. All-in-all, it's a good scheme for anyone worried about unexpected bills.

Useful link: How you manage your O2 spending cap

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


Not as good as:

Equal to:

Shared plans/multibuys: O2 does an alright but not great job

O2's Family Plans

Discounted additional plans and share dataFamily Plan discounts

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If you've got children with mobile phone deals you're paying for, you could be better of with a family mobile plan that combines everyone's contracts onto one account, getting you a discount and simpler bills.

O2 offer some pretty decent discounts for taking multiple deals with them, particularly if it's SIMs you're after. Although we'd argue, you need the discounts with their higher starting prices.

Add another phone or SIM to your account and you'll receive 10% off the airtime cost of the first extra product, 20% off the second, 30% off the third and 40% off the fourth and any extras up to 20 more.

On phone contracts, it's worth understanding that's not a discount off the total bill. But rather off the minutes, texts and data part of your deal. The cost of the device itself is on a separate non-discountable plan.

You can combine this with O2's Sharer Plans too, which let you share the data from one main phone or tablet contract, with other plans on the same account.

Useful link: Calculate Family Plan discounts

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


Better than:
All others

Data rollover: O2 only offer it on Pay As You Go

O2 data rollover on pay as you go

Some providers let you keep data you haven't usedSee PAYG SIMs

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Everyone's data usage changes month to month. Sometimes you'll have loads left over, sometime you might even go over your monthly limit and paying for an extra to see you through to next month.

Some mobile providers have started to recognise this and have come up with an interesting concept that generally gets called data rollover (see all networks with data rollover here).

These special plans either carry forward any data you've not used so you can use it in the next month. Or they put unused data away in a kind of bank account that you can withdraw from whenever you need.

O2 don't include this benefit with their pay monthly phone contracts or SIM only deals. But you do now get to keep unused data for one month with their pay as you go Big Bundles, as long as you buy a new bundle next month too.

Useful link: Networks with data rollover plans on pay monthly

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

Joint 5th

Equal to:
EE and Vodafone

Data saving schemes: no free data for streaming/messaging

Sky Mobile unlimited streaming

Stream Sky TV apps without using dataHow it works

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One new way that some networks are adding extra value to their deals is by giving you free data to use for streaming or social media, which doesn't come out of your allowance.

O2 don't offer anything like this. But Sky Mobile, who use the O2 network, do. Every Sky plan lets you stream any of their TV apps without it using up data. It's incredibly generous. Here's the cheapest plan with the benefit:

Read our full O2 vs Sky Mobile guide for all differences between the network. For the same coverage, speeds and generally cheaper deals, we think Sky are definitely worth looking at.

Other free data schemes include Three's Go Binge that lets you watch services like Netflix on your phone without using up data on selected plans (we've reviewed Go Binge here).

Useful link: We find the best free data scheme in the UK

Our free data rating:
★☆☆☆☆ (poor)

Equal to:
Everyone else

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?

O2's 6 months Disney+ offer

O2's Disney offer banner

See all offers

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O2 are now including a Disney+ subscription at no extra cost with all their pay monthly O2 Refresh phone contracts and 12/18-month SIM only plans, which would regularly cost £5.99 a month.

That includes this SIM only plan, which is O2's most competitive and is available until 10th June:

Useful link: See all O2 current offers

SIM only contracts on O2

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

O2 SIM only tariff fact file

Find a SIM only plan

We've pre-filtered for O2 and networks that use them



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Added features

Phone contracts on O2

We look at the pros and cons of taking a pay monthly phone with O2:

Build your own plan with O2's new custom phone plans

O2's customisable plans

How custom plans work

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O2 have introduced customisable plans on their pay monthly phones, which let you individually choose a contract length anywhere between 3 and 36 months, an upfront cost and the amount of data you want.

The benefits of this are pretty clear: you can spread the cost of the phone out over a period that makes the monthly cost affordable to you, you choose how long you're tied in, and you can pay as much or little up front as you have in your budget.

When you're confronted with so many choices though it can be tricky to decide, and it becomes way harder to compare costs and calculate the best deal. But there's nothing sneaky in the way O2 price these deals:

Whichever contract length or upfront cost you choose, the total cost of the device stays the same, and so does the cost of the minutes, texts and data plan. In other words, there's no winning or losing combination where it becomes more expensive or cheaper to change your payment terms (other networks are guilty of this).

Our advice would be to tie yourself into a deal as short as possible but make sure you can manage the higher monthly payments this will cause.

Useful link: How building your own plan works

Upgrade early with O2 Refresh tariffs

Early upgrade with O2 Refresh

About early upgrades

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The most important thing to realise with O2's smartphone contracts is that they're based on splitting your overall deal into two parts: one for the cost of your device, the other for your minutes, text and data.

Virgin, Sky, giffgaff and Tesco offer similar deals. O2 call theirs Refresh. They're based on credit agreements (basically loans) for your phone, which you pay back over a set period.

The key advantage for you is that you're free to pay the full cost off early at any point if you have the spare money. At that point you're able to upgrade to a new phone, or leave O2 entirely.

Also, once the device has been paid off in full, you won't keep paying for it. So if you do nothing, the cost of your bill will drop to the amount you're paying your monthly minutes, texts and data only.

But you should know that taking this type of contract is a serious obligation: you're basically taking out a loan for hundreds of pounds. If you've had debt issues before you're unlikely to be accepted for this type of contract.

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

O2's Pay As You Go

Don't want to pay monthly? We look at if O2 are a good option for you

O2 no longer offer traditional PAYG

Expired stampO2's classic pay as you go plan

See bundles

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O2 have now gone the way of practically other network and binned their traditional pay as you go tariff, where you just top up with credit and pay for what you use out of that. They've moved towards pre-paid bundles instead.

If you want old-school pay as you go on the O2 network, have a look at giffgaff here:

Or 1pMobile on the EE network have the cheapest overall rates:

Price-wise we don't really see why you'd join O2 on a Big Bundle, unless you've failed a credit check. Again, we'd join giffgaff or Tesco if that was the case. Here's how O2, Tesco and giffgaff's pre-paid options compare:

O2 Mobile Broadband

We look at whether it's worth taking a data SIM or dongle from O2

There are plenty of choices for tablet data SIMs and dongles

O2 Mobile broadband

See data-only plans

(opens in new window)

O2 make a decent choice for a data-only SIM or mobile broadband device. Extensive 4G coverage is useful for train journeys and other places out of the home or office, even if the speeds aren't the fastest.

On SIM only, you've got a choice of 12-month contracts, 1-month contract (£2 more a month) or pre-loaded SIMs. We'd probably take a 1-month deal first to try, before moving to a cheaper, longer commitment once happy.

We really don't rate O2's preloaded SIMs. Most options, the data expires after 1 month, so you might as well get a cheaper contract deal. And the 12 month expiry options are priced so high that they're basically pointless.

If you're after a mobile broadband device too, O2 have a standard range of pocket hotspot devices and dongles. We'd go for a mobile WiFi one over a dongle as it can be used with multiple devices at one.

The device costs around £20 - £30 spread over your chosen contract length, which is decent value. And then your data plan is priced roughly the same as O2's data SIMs.

Useful link: All benefits of O2's Mobile Broadband plan

O2 customer service reviews

Customer service: O2 always score well in Ofcom complaints data

Ofcom complaints data

O2 receive fewer complaints than averageSee all O2's awards

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It's practically inevitable with a mobile network that people are going to experience problems from time to time. The important thing is how well providers deal with their customers' issues.

That's why we use Ofcom's data on how many complaints they receive about each network to determine our customer service scores. If Ofcom receive a complaint, it means the provider hasn't resolved it themselves.

We had a genuine problem with the SIM card we ordered, where it was only ever connecting to a 3G signal, despite being in a 4G coverage area.

This gave us a great chance to speak to their customer services for real. Their technical issues team were based in the UK and very professional at trying to diagnose the problem.

It did take a number of days and different solutions for the problem to be finally solved. But O2's communications were good and they offered financial compensation for the wasted days having no 4G.

We can see why O2 historically have a good reputation within the industry and the government regulator Ofcom.

O2 have a great reputation for looking after their customers and this is reflected in the Ofcom data, which shows they receive fewer complaints per 100,000 customers than the industry average.

If you've had grief with your previous provider, Ofcom's data suggests you're less likely to have a bad experience on O2. Our own experience found them easy to deal with.

Useful link: How to get help on O2

More O2 guides

Other mobile network reviews

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