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Three vs O2: comparing their 4G/5G network coverage, speeds and benefits

Three vs O2

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Will you get a better 4G/5G signal on O2 or Three? Which has faster speeds? Who has the best roaming? Our comparison reveals the answers. SIM Sherpa is your trusty guide. Last updated: 10th January 2020

What we compare in this guide

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Three's hidden unlimited data deal

Pay only £18 a month for unlimited everything with Three's hidden £18 a month unlimited data SIM only offer (12 month contract).

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Comparing O2 and Three's networks

Network coverage: do Three or O2 have better signal?

Comparing O2 and Three's 5G, 4G and 3G coverage across the UK

Mobile signal bars with O2 and Three logos

O2's 4G covers more of the country than Three's

O2 best network for coverage banner

See network awards

(opens in new window)

Even though both Three and O2 report 99% population coverage for 4G, it's important to remember that's just signal in the places people live. For signal away from residences, we're confident O2 is the larger network.

Independent testers Opensignal report that O2 customers spend 85.7% of the time with a 4G connection, while on Three's it's a lower 76.2%. O2 have more of the physical landmass of the UK covered.

That said, if you mainly use your phone somewhere Three do cover (and they've got fine signal in most towns and cities), there's no problem. So use the checkers below before ruling either out.

If you've ever had poor indoor signal for calls, O2's 2G/3G is broadcast on better frequencies than Three for getting into buildings. Though Three's WiFi calling can improve this if your phone has the feature.

Useful link: What Three say about their network

Both networks are rolling out their 5G fast

Three's 5G locations map

See all 5G cities

(opens in new window)

The space race between mobile networks to bring 5G data coverage to as many places as possible has already begun, even if we're still talking about a city-by-city basis, rather than as a national percentage.

O2 are currently on 30 locations in the UK, while Three have 5G in 68 places - with both networks targeting different parts of the country (these numbers are growing constantly.

We would point out though that saying there's 5G in a city, doesn't mean the whole city has it (check street-by-street using their maps below), because all networks focus on busy parts like stations and event venues.

Useful link: The next places to get Three's 5G

Use O2 and Three's coverage checkers

Check at home, your route to work/school and anywhere you'll use your phone

Three's coverage checker

Three coverage checker

Check Three signal

on their official map
(opens in new window)

O2's coverage checker

O2 coverage checker

Check O2 signal

on their official map
(opens in new window)

Our verdict on coverage:

O2 win

"Despite huge improvements in Three's 4G reach, O2 still have more of the UK's landmass covered with their 4G. Plus O2 having 2G could be useful if you're right out in the sticks. Don't rule either network in or out before you've checked their signal where you'll use your phone."

Compare pricing and deals

Download speeds: are O2 or Three faster?

Which has faster 4G and 5G data?

O2 and Three logos with a speedometer icon

Three's 4G downloads around 20% faster than O2

Three best network for data banner

See Three's awards

(opens in new window)

While O2 beat Three for how much of the country they bring 4G to, they've achieved this at the expense of download speed. O2 are the slowest network in the UK.

Independent speed testers Opensignal and Speedtest by Ookla take millions of measurements on smartphones on each mobile network and they consistently put Three's 4G ahead of O2's.

O2's were clocked typically between16.95 - 18.00 Mbps, while Three's averaged 21.60 Mbps. O2's is like copper phoneline based home broadband, while Three's is more like a low-range fibre connection.

The difference isn't huge. And basic users will probably be happy on either. For more demanding usage like HD videos, Three is more suitable and O2 could start to creak a little.

Useful link: Three carry more data than any other network

Three say their 5G will be the UK's fastest

Three fastest 5G network banner

Read why

(opens in new window)

If you're planning on making the step to 5G, Three are saying that they will have the fastest 5G network, because they've bought the most radio spectrum to transmit it on, so it could be worth the wait.

There's a lot of speculation banded about in terms of how fast 5G can be. The top potential is about 1 Gbps, which is like the very best home fibre optic broadband connection available.

From what Three are saying, they'll be better placed to hit that potential top-end than any other network, including O2. So if you're a mega-demanding user, they could end up being your best choice.

Rather than speed, we actually think the biggest benefit of 5G will be capacity. That means not having your connection grind to a halt when you're in busy places. Three having more spectrum should help with that too.

Useful link: Why Three say only theirs is real 5G

Our verdict on data speeds:

A win for Three

"You're more likely to receive a faster general 4G service with Three, than O2, even if top speeds do vary place-to-place. If speed's something you care about, the choice is reasonably simple."

Compare pricing and deals

WiFi calling on Three and O2 compared

O2 and Three both offer WiFi calling. We look at which is best

WiFi calling symbol with O2 and Three logos

Three's inTouch WiFi calling also supports SMS texts

Three WiFi calling

See Three's scheme

(opens in new window)

The benefits of networks' WiFi calling schemes are that you can make calls (and send texts on some networks) in places where you've got no mobile signal but you do have WiFi.

Everybody on Three automatically gets access to their WiFi calling scheme called 'inTouch', whether you pay monthly or pay as you go, as long as your phone is one of the supported devices listed here.

Three are the most confident network about supporting WiFi calling on Android phones that weren't bought from them, which can be an issue with other providers. iPhones tend to be compatible across the board.

Where Three have the edge over O2 is that inTouch also supports SMS text messages, which is useful now that many services like banks send you confirmation codes via conventional SMS.

Useful link: See full details and supported devices

O2's WiFi calling scheme doesn't support texts

O2 WiFi calling

See O2's scheme

(opens in new window)

The main point of difference between O2's WiFi calling and Three's is that O2's does not support SMS text message over WiFi. O2's indoor signal is likely to be better than Three's though anyway.

You'll only get WiFi calling included if you join on a pay monthly plan. Pay as you go customers don't get the feature. And you have to manually turn it on in your account, which is a bit irritating.

O2 are a little more hesistant to say they'll support Android phones not bought from them - although our test with a manufacturer-bought Samsung did work (see full device list here).

If it works, the basic functionality of O2's WiFi calling is fine. And you can move from WiFi to a 4G calling without the call dropping, which is handy too.

Useful link: Read all benefits and restrictions at

Our verdict on WiFi calling:

Win for Three

"Not only do we think you've got a better chance of Three supporting your phone than O2 but you'll also get the useful advantage of SMS text messaging over WiFi."

Compare pricing and deals

Extra network features: WiFi hotspots on O2 and Three

Do you get more free WiFi access on Three or O2?

WiFi symbol with O2 and Three logos

O2 customers tap into 15,000 free WiFi hotspots across the UK

Free O2 WiFi hotspots

Access free O2 WiFi

(opens in new window)

It's good when a mobile network can give you free access to WiFi when you're out and about because it saves you using up your monthly allowance of mobile data and WiFi can offer a faster connection.

So one handy benefit for O2 customers is getting free access to 15,000 hotspots on the high street (find hotspots near you with O2's map here).

The unique perk for O2 customers is that around 4000 of these can be automatically accessed without having to log in.

The hotspots recognise your O2 SIM and will connect you if they can offer a better speed than your current mobile data connection.

Useful link: How free O2 WiFi works

You can actually still access O2 WiFi on Three for free

Free WiFi on the Underground

How it works

read Three's official guide
(opens in new window)

O2 WiFi hotspots are actually still a free service for anyone, whether you're on O2 or not. The only difference for non-O2 customers is you'll need to login each time you want to access a hotspot.

For that reason, it's difficult to say that O2 has a huge upper hand on Three for free WiFi.

For Londoners, you'll also get free WiFi on the London Underground as a Three customer. That gives you an internet connection at over 250 stations across the network.

You also get this on O2 so it's not unique to Three, meaning there's actually little to split the two networks when it comes to the free WiFi access you get included..

Useful link: How to get free WiFi on the Underground with Three

Our verdict on free WiFi:

Minor win for O2

"Connecting automatically to some O2 WiFi hotspots is a handy little benefit for O2 customers, although we'd probably not make it the crucial deciding factor between the two."

Compare pricing and deals

Comparing perks and benefits on O2 and Three

Inclusive streaming or subscriptions: O2 vs Three

Some networks now offer free data for streaming, we compare Three and O2

A phone streaming video and O2 and Three logos

Stream Netflix and others as much as you like with Three

Three Go Binge streaming

Read more

(opens in new window)

We've all probably held back from watching videos on our phones, because of the data it will use. But if you get the right plan on Three, you might not need to any more:

Take a pay monthly plan with 12GB or more data and you can now use selected video and music streaming services as much as you like, without them using up your regular data allowance.

It’s called Go Binge and it’s essentially an unlimited data allowance for streaming. The apps it covers includes Netflix and 4x other video and music streaming providers, which we detail in our review here.

As streaming is one of the quickest ways to use up your data, this is a welcome move that will let you get more out of your phone, without having to buy a large plan. It’s not something O2 currently offer.

Useful link: Learn everything about Go Binge in Three's own guide.

O2 offer time-limited free trials with Extras

Extras on O2

See all choices

(opens in new window)

There's no similar unlimited streaming data schemes to Go Binge on O2. But they have recently introduced a new benefit that does get you a free trial to a streaming app.

It's called Extras. And you get it included on selected O2 Refresh phone tariffs or SIM only plans, basically the more-expensive ones (so O2 are using them to persuade you onto higher tariffs).

When you take one of those plans, you can choose to add a free trial lasting up to 6 months of Amazon Music, Prime Video or Audible, or any of these other apps.

We'd stress that the services become payable after the free trial, so this isn't O2 being particularly generous. But if you remember to cancel or don't mind paying, it's still a freebie you wouldn't otherwise get.

Useful link: Full O2 Extras FAQs

Our verdict on free streaming giveaways

A clear win for Three

"Getting the data free for streaming permanently is way more valuable than getting a singular time-limited trial of a streaming app and still paying for the data."

Compare pricing and deals

Inclusive roaming: O2 Travel vs Three Go Roam

Now every network has to offer free EU roaming, we see if inclusive roaming on O2 has caught up with Three

A globe with O2 and Three logos

Roam in 71 countries worldwide at no extra cost with Three

Three Feel At Home roaming

See all countries

(opens in new window)

Now that all networks must offer free EU roaming, the key difference between networks is where else in the world they let you use your minutes, texts and data. And how much that costs.

For us, Three have the better scheme. Better than O2, and better than all the other networks. It's all to do with the number of extra countries, and the amount of plans you get it included with:

Their Go Roam scheme lets you use up to 13GB data, 5000 texts and 3000 minutes out of your plan's regular UK allowances while in any of the 71 countries listed here, for no extra charge.

It comes with every phone contract from Three, as well as pay monthly SIM only, and pay as you go All-in-one bundles. Even the cheapest plans include it, which isn't true on O2.

Useful link: See where you can go and full terms and conditions

O2's inclusive worldwide roaming is limited to more-expensive deals

Free O2 EU roaming

Free EU roaming

in O2's international guide
(opens in new window)

Like all networks, O2 now let you use your regular UK minutes, texts and data within the EU for no extra cost. Join on the right plan, and they offer something that gets close to Three's Go Roam too:

SIM only plans over £20 a month, and most smartphone plans over 4GB (O2 flag which ones), give you free access to O2 Travel Inclusive Zone, which gives you free roaming in these 27 extra non-EU destinations.

Instead of calls, texts and data coming out of your normal plan, O2 give you a daily batch of 120 minutes and 120 texts back to the UK, plus an undetermined amount of data (likely around 100MB or so before being slowed down).

It's less generous than Three's Go Roam and O2 are making you spend extra to get it. If your O2 plan doesn't include it, you can buy daily add-ons or pay as you go (see costs of each here).

Useful link: Learn about free EU roaming and other costs

Our verdict on inclusive roaming

A clear win for Three

"In terms of number of destinations you can visit without paying extra for roaming, Three not only beat O2 but all other mobile networks. Not bad when you consider Three are usually cheaper than other providers too."

Compare pricing and deals

Loyalty reward schemes: can Three challenge O2 Priority?

We look at whether O2 or Three look after their customers best with daily rewards

A hand with a heart with O2 and Three logos

O2 Priority is still the UK's best rewards scheme for mobile customers

O2 Priority rewards scheme

See available deals

(opens in new window)

Their plans might not be the very cheapest around but O2 make up for that in part by giving all 22 million of their customers to the reward scheme O2 Priority. For us, there's no better scheme of this type.

It's basically a bit like a club where high street and online retailers post exclusive offers and discounts that only O2 customers benefit from. That can be on shopping, food, travel and more.

Priority members also get first dibs on tickets where O2 are the venue or event sponsor, plus special treatment while you're at the event itself (here's some examples of what to expect).

If you use Priority correctly for things you were going to pay for anyway, it makes a good way of clawing back some or all of the monthly cost of your phone or SIM deal.

Useful link: See everything you get with Priority in O2's full online guide

Three have axed their 'Wuntu' app

Read why it closed

(opens in new window)

You might not have heard about it but Three had their own version of O2's Priority for a while, which they called 'Wuntu'. Wuntu Three - get it? The scheme is now closed for good.

Some of the principles of Wuntu were the same as Priority: they offered up daily exclusive offers with high street and online shops, food and drink, and more.

There were some interesting complete freebies, typically limited to the first few hundred or so customers for things like pizza or coffees.

What it missed in comparison to O2 Priority was any of the event ticketing benefits, like first dibs on music gigs and sports matches but overall we'd still rated Wuntu as a nice bonus on top of Three's other benefits.

Useful link: Three's statement about Wuntu

Three now get their customers free upgrades when flying easyJet

Three easyJet offer

See easyJet offer

(opens in new window)

With Go Roam, Three have styled themselves as the best network for roaming, and their new partnership with easyJet is a nice addition on top of that:

Every pay monthly phone or SIM only contract customer on Three gets free upgrades to easyJet's Hands Free scheme, which helps you pass through the airport more smoothly.

You'll get to check your hand luggage at a dedicated desk, walk through security with no luggage more quickly, board the plane just after Speeding Boarding, and pick up your priority-marked bags at the end first.

It's a decent package that would normally cost £5 per single journey. Three customers get it free when travelling from the UK only (not on the way back).

Useful link: How to get your free easyJet upgrades from Three's full guide

Loyalty programmes

Win for O2

"Now that Three have closed their rival Wuntu app, we think O2 Priority beats Three's easyJet upgrades as a more useful benefit on a daily basis."

Compare pricing and deals

Comparing pricing and deals on O2 and Three

SIM only plans: how prices compare on O2 and Three

Are Three's SIMs always cheaper than O2's?

O2 and Three logos with a SIM card
Deal options >
Mins, texts and data >
Data speed (4G or 5G) >
Max contract length >

Close options








Minimum data speed


Maximum contract length

1 month
12 months

Close filters

Choose which networks you'd consider:

Three logo
BT Mobile logo
EE logo
giffgaff logo
ID logo
Lebara logo
O2 logo
Plusnet Mobile logo
Sky logo
Talkmobile logo
Tesco logo
Virgin Mobile logo
Vodafone logo
VOXI logo

SIM only plan prices

A win for Three

"Use the deal finder above and you'll notice Three's SIMs are usually cheaper for the same minutes, texts and data. Keep an eye out for special offers that can even out the playing field from time to time."

Compare pricing and deals

Special offers available on O2 and Three

Here's what promotions Three and O2 have running this month

O2 and Three logos with a special offer ribbon

Hidden £18 unlimited data deal on Three

Three's hidden unlimited data deal

See full offer

(opens in new window)

Pay just £18 a month for Three's hidden unlimited data SIM only deal:

This deal is better value than the 24‑month plan currently being advertised with six months at half price, which averages out to £19.25 a month over the course of the contract.

Or if you don't need that much data, it's worth looking at Three's hidden 8GB for £8 offer or 12GB for £10 deal.

If it's a phone contract you're after, be sure to check you can't get a better deal with our hidden phone offer page here.

Useful link: See all latest Three offers

Phone contracts compared on Three and O2

Are O2 or Three cheaper for taking a pay monthly smartphone deal?

O2 and Three logos with smartphone icon

O2's smartphone contracts are a lot more flexible than Three's

O2 custom plans

See custom plans

(opens in new window)

If you've not heard about them, O2's custom plans are worth a look. These let you pick your own contract length anywhere between 3 and 36 months, plus how much you're willing to pay up front.

The benefit of this is you can pick a deal that matches your monthly budget. If you can afford it, you can choose a shorter term and pay more per month. Or if you want a lower monthly payment, choose a longer contract.

This all works because O2 split their phone contracts into two parts: a loan for the cost of your phone, and a plan for your mins, texts and data.

Changing the contract length keeps the total cost of the phone the same, it's just spread over a different number of months.

The other advantage of having a phone on a credit agreement is that you can upgrade early or leave by paying it all off at once whenever you like. The downside is you're need a good credit rating to be accepted on O2.

Useful link: Use our phone contract comparison tool

Three's phone contracts are generally cheaper than O2 and simpler

Compare phone contract prices

Use phone deal finder

(opens in new window)

With Three, there's not as much flexibility as on O2 with your phone contract. They offer what we'd call regular 24-month mobile contracts, where the cost of the phone, your minutes, texts and data, are all bundled into one single payment.

This means it's a lot simpler to compare prices and choose the right deal. It could also means it's easier to get accepted for a deal with Three, because there's no finance involved (note: we have no specific info on Three or O2's credit policy).

Generally, we'd say Three will work out cheaper than O2 but it will all come down to what deals are live at the time that you buy. Use our comparison tool to compare.

Useful link: Use our phone contract comparison tool

Choose a manufacturer

Which make of phone do you want?

Find a plan for your phone

Choose what you want from your deal

Deal options >
Mins, texts and data >
Data speed (3G or 4G) >
Max contract length >
Max upfront cost >

Close options








Maximum contract length

12 months
24 months

Upfront cost

Any upfront cost


Close filters

Choose which networks you'd consider:

Three logo
BT Mobile logo
EE logo
giffgaff logo
ID logo
O2 logo
Sky logo
Tesco logo
Virgin Mobile logo
Vodafone logo

Our verdict on phone contract prices:

Three marginally cheaper

"We can say Three are cheaper on average than O2 but the smart thing to do is use our comparison tool to look at precise costs for the mins, texs and data you want."

Compare phone prices

Compare Three against other networks

Compare Three with EE

Three vs EE

Read Three vs EE

Compare Three with Vodafone

Three vs Vodafone

Read Three vs Vodafone

Compare Three with BT Mobile

Three vs BT Mobile

Read Three vs BT Mobile

Compare Three with giffgaff

Three vs giffgaff

Read Three vs giffgaff

Compare Three with SMARTY

Three vs SMARTY

Read Three vs SMARTY

Compare Three with Virgin Mobile

Three vs Virgin Mobile

Read Three vs Virgin Mobile

Compare O2 with other networks

Comparing O2 and EE

O2 vs EE

Read O2 vs EE

Comparing O2 and Vodafone

O2 vs Vodafone

Read O2 vs Vodafone

SIM Sherpa can help you find your next SIM only deal

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