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Three vs O2: signal, speeds and coverage on their 4G networks in 2019

Three vs O2

Will you get a better 4G 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: 17th January 2019

What we compare in this guide

Quality of their mobile networks
Three vs O2 mobile networks

4G and 3G coverage
Download speeds over 4G and 3G
Extra features: WiFi calling and hotspots

Compare their networks

Perks and benefits on O2 vs Three
O2 and Three perks and benefits

Unlimited streaming data
Free and inclusive roaming deals
Loyalty and reward schemes

Compare perks and benefits

Deal prices on O2 and Three
O2 and Three prices and deals

Compare their SIM only plans
Smartphone contracts head-to-head
Extra costs and price increase

Compare deals and prices

Quick update on latest offers

Three's hidden £20 100GB offer

Three 100GB SIM

Use our hidden offer link below to get a 100GB for £20 SIM only deal that's not advertised on the main part of Three.co.uk:

100GB data, unlimited mins and texts for £20 a month (12‑month SIM only contract)

See all Three's offers > (opens in new tab)

O2's 25GB for £20 18-month SIM

O2's 25GB for £20 SIM only deal

If you're willing to commit to a longer 18-month SIM only contract, you can get O2's best pricing including:

25GB for £20 a month (18-month contract)

See all O2 18-month SIMs > (opens in new tab)

Comparing the quality of O2 and Three's networks

Network coverage: do Three or O2 have better signal in general?

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

Three vs O2 mobile networks

O2 and Three's 4G population coverage is now about even

O2 4G coverage
Three 4G coverage
99%
99%

If you look at the latest statistics on the percentage of the UK population (households) that O2 and Three bring 4G to, there's no longer a real difference: O2's 4G reaches 99%, as does Three's.

In terms of how much of the physical geographical UK each network covers, O2 is still larger. Meaning you've got a better chance of getting 4G where people don't live, like roads and on trainlines.

With both networks, we'd advise checking coverage below before signing up. And not just looking up where you live, but all the places you'll use your phone.

Three and O2 are practically level for 3G too

O2 3G coverage
Three 3G coverage
99%
98%

According to the statistics, O2 and Three have roughly the same 3G coverage as a percentage but the specific areas where they have it will vary.

3G is still used for making calls and sending texts, so it's still important. Also, it steps in when there's no 4G where you are. It's slightly slower but still gets the job done.

Another thing to note is that Three have no 2G signal at all. This is useful for calls and ultra-slow internet when you're in the middle of nowhere. O2 cover 99% population with 2G.

Checking coverage: find out O2 and Three's signal strength near you

Statistics give a general idea but we recommend using coverage checkers to make sure O2 or Three have signal in your local area:

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 narrow 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 4G and 3G data faster on O2 or Three?

We find out whether Three or O2 are proven to be faster

O2 4G vs Three

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

Three 4G speeds
O2 4G speeds
20 Mbps
16 Mbps

While we've seen above that O2 bring 4G to more places than Three, when you have a 4G connection, we'd expect faster speeds on Three than O2 in general.

O2 customers are typically looking at 4G download speeds around the 16 Mbps mark. While Three customers can expect to go faster with speeds around 20 Mbps.

That could make the difference of having videos buffer on O2, while they run smoothly on Three. But for general internet browsing O2's speeds are ok and aren't painfully slow. It depends what you want to do.

Three have faster 3G than O2 too

Three 3G speeds
O2 4G speeds
8 Mbps
4 Mbps

It's a simple fact on any mobile network, sometimes you're going to find yourself in an area where there's no 4G and you'll have to use 3G data instead.

Here, we'd expect Three customers to get 3G speeds considerably faster than O2:

O2 customers are looking at around 4 Mbps over 3G. That compares to a much healthier 8 Mbps over 3G on Three. A much less frustrating experience.

Our verdict on 4G/3G speed:

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

Extra network features: WiFi hotspots on O2 and Three

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

Free O2 WiFi hotspots

Access free O2 WiFi

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

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

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 often offers 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: Here's how free O2 WiFi works from their official website

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: Here's how you get free WiFi on the Underground with Three from their official website

Extra network features: WiFi calling on Three and O2 compared

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

Three WiFi calling

See Three's scheme

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

Three's inTouch offers seamless WiFi calling for modern devices

The benefits of networks' WiFi calling schemes are that you can make and take calls and texts in places where you've got no mobile signal but you do have WiFi, a real bonus if there's no reception inside your house.

Everybody on Three gets access to their WiFi calling scheme called 'inTouch', whether you pay monthly or pay as you go, even if you didn't buy your phone from Three in the first place.

If you've got one of these more-modern devices listed here on Three's site, you can download a software update that will let you use WiFi calling.

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 in Three's own guide to their WiFi calling feature

O2's WiFi calling scheme used to be more flexible

O2 WiFi calling

See O2's scheme

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

We used to rate O2's WiFi calling as being just as good as Three's because they had an excellent app called 'Tu Go' that let you use WiFi abroad to make calls at no extra cost.

That's now been scrapped and O2's main WiFi calling scheme has quite a few more restrictions on which devices it works with:

For Android phones, you’ll need to have bought your handset from O2 directly, so that the correct software is pre-installed. If you didn’t, WiFi calling won’t work (iPhones are more flexible).

You’ll also only get WiFi calling on O2’s pay monthly plans, whereas it also works on Pay As You Go with Three.

Useful link: Read all benefits and restrictions at O2.co.uk

Extra network features

Honours even

"O2's free WiFi hotspots are a lot more comprehensive than Three's, but we rate Three's WiFi calling scheme a lot higher than O2's. So it could coverage, 4G speeds and plan pricing that make the difference for you."

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

Stream Netflix and other selected providers as much as you like with Three

Three Go Binge streaming

Read more

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

Three have always been innovative in what they offer their customers and now they’ve stepped it up again:

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.

Including Netflix, there are 4x streaming providers covered by Go Binge, which we detail in our review here.

All Three’s pay monthly SIM only and phone contracts with at least 12GB data now come with Go Binge as standard. Go Binge works as long as you still have some data left each month (see all conditions 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.

Free streaming data

A clear win for Three

"Three's Go Binge is the most comprehensive free streaming data scheme out there today. O2 don't offer anything similar, and have been totally left behind in this area"

Compare pricing and deals

Free and inclusive roaming: can O2 match Three's Go Roam?

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

Roam in 71 countries worldwide at no extra cost with Three

Three Feel At Home roaming

See all countries

at Three.co.uk
(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 at Three.co.uk

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 in O2's international hub

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

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

O2 Priority rewards scheme

See available deals

at O2.co.uk
(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 their launched 'Wuntu' app as a direct challenger to Priority

See example offers

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

You might not have heard about it but Three have quietly launched their own version of O2's Priority, which they call 'Wuntu'. Wuntu Three - get it?

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

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

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

Useful link: See what you get with Three's Wuntu app in their dedicated section about it

Three now get their customers free upgrades when flying easyJet

Three easyJet offer

See easyJet offer

at Three.co.uk
(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

Score draw

"We used to say that O2 Priority trumped Three's Wuntu in this category. But now Three have added easyJet upgrades, we'd say it's more of a level playing field. It's all about deciding which perks you think you'd actually use."

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?

Three's SIM only deals tend to work out cheaper than O2's

Both Three and O2 offer SIM only contracts on 12-month and shorter 1-month contracts, typically starting from around £9 a month with Three and £11 a month with O2.

Of course, the actual price difference depends on current offers and the precise plan you choose. So use our comparison tool below to quickly compare their current plans against each other:

Choose what you want in your deal:

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Showing SIM only deals with at least
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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's cheaper 18-month SIM only deals

O2's best SIM only deal

See all SIM offers

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

If you're willing to commit to a longer 18-month contract on SIM only, O2 have improved pricing on these three plans:

25GB for £20 a month (18-month contract), 40GB for £25 a month (18-month contract) or 60GB for £28 a month

It's also often worth checking out Carphone Warehouse's O2 cashback offers here, which occasionally work out better than going direct with O2 and qualify to get an automatic cheque through the post.

Useful link: See all O2's latest offers

Three's hidden 100GB for £20 offer

Three 100GB SIM

See hidden offer

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

Use our link below to get Three's hidden 100GB for £20 SIM only offer that's not available on the main part of Three.co.uk:

Or for £2 a month extra, you can get unlimited data for £22 a month on a 12-month SIM only contract.

If you're after a smartphone, Three have cut prices on the unlimited data plan on all of these phones, including iPhone 8, XR and Samsung Galaxy S10 range and S9.

Useful links: See all latest Three offers

Phone contracts compared on Three and O2

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

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

O2 custom plans

See custom plans

at O2.co.uk
(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

at simsherpa.com
(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

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

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