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BT Mobile vs Three: comparing 4G/5G coverage, speeds and benefits

BT Mobile vs Three

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We compare Three against BT Mobile to see which you're better off joining, for the best network coverage, 4G speeds and deals. Here's what we found. SIM Sherpa is your trusty guide. Last updated: 9th March 2020.

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Which has the better network?

Coverage: do Three or BT Mobile have a bigger network?

A look at whether you can expect better signal on BT Mobile or Three

Three and BT logos with some mobile signal bars

BT Mobile are ahead of Three for 4G data coverage

BT Mobile logo
Three logo

For calls, there isn't much of a difference between the coverage stats for BT Mobile and Three. Both reach 96% of UK residences indoors and 99% outdoors. And around 85% of the UK's landmass away from homes.

For 4G data, BT Mobile have the advantage over Three by using the EE network. They've got the most amount of the UK's landmass covered (84% vs 79%). But in places people live there's not a huge difference.

Top-level statistics are one way to get a general feel for a network's coverage but in real-life you'll find different providers are better in different areas. We'd advise thinking about where you'll actually use your phone.

Use the network maps below to check both networks' local coverage near you. Don't just look at home, look at your route to work, school and anywhere else you'll take your phone.

5G is in its early stages on both networks

BT logo
80 places
68 places

There's a bit of a space race on between mobile networks to bring 5G to the most cities possible. The count changes constantly but Three and BT have it in 68 and 80 places respectively at the time of writing.

The targeted towns/cities are different ones. And within those places, it's still very much a street-by-street basis too, with 5G mostly located in high traffic places like train stations, high streets and event venues.

From both providers', 5G coverage checkers, we'd say BT have larger parts of the cities covered that they report having 5G in. Three's 5G seems to be available in smaller concentrations within the cities they're in.

Use Three and BT's network maps

It's worth giving their signal a double check everywhere you'll use your phone

Three's coverage map

Three coverage map screenshot

Check Three signal

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BT Mobile's coverage map

BT Mobile coverage map screenshot

Check BT coverage

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Our verdict on coverage:

Still a win for BT Mobile

"Although we'd say BT Mobile's coverage is better nationally, we wouldn't rule Three out until you've checked your local signal on both, because urban users are unlikely to notice a difference."

Compare pricing and deals

4G speeds: are Three faster than BT Mobile?

A look at the expected download speeds on each network

BT and Three logos with a speedometer

We expect BT Mobile to be faster than Three on average

Three's Real 5G network banner

Read why

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4G download speed is an area where it's an advantage for BT Mobile to be using the EE network over Three. We expect typical 4G download speeds to average almost 50% faster on BT.

That said, the majority of BT plans have a speed cap of 30 Mbps, while Three will let you faster than that where higher speeds are available, so it's impossible to say Three are always slower.

Both networks' speeds are above the 20 Mbps that we consider adequate for the majority of users. You'll be able to stream HD videos buffer-free at that speed for example.

If you're an early adopter and have a 5G-ready phone now, Three are saying their 5G will be the UK's fastest, because they've got more radio spectrum for it than any other network (read full story here).

Useful link: Read about Three's 5G rollout plans

You can pay for speed upgrades on BT Mobile where available

BT Mobile Extra Speed location map

See Extra Speed areas

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BT Mobile's standard top speed over 4G is capped at 30 Mbps on most their plans, even though their hosts EE are capable of delivering a lot faster than this. This is basically so they can sell you an upgrade.

On SIM only and phone contracts, BT's plans with the largest amounts of data (the most expensive) come with "4G Extra Speed", capped at 60 Mbps instead. On regular plans, you can buy this as a monthly add-on too.

Before deliberately paying extra to get this, have a check of BT's map here to make sure they definitely offer the extra speed in your area. Enter the location and then tick the "Extra Speed 4G" filter.

Three don't split their plans into speed tiers. Each comes with the top speed they can deliver, including 5G at no extra cost if it's in your area and your phone is 5G-ready.

Useful link: More details about BT Extra Speed 4G

Our verdict on data speeds:

A win for BT Mobile

"Until 5G availability is more widespread and more people's phones have the feature, 4G data speeds are still more important. And BT have an obvious advantage over Three for 4G still."

Compare pricing and deals

WiFi calling: is BT Mobile as good as Three?

Making calls over WiFi when there's poor signal

WiFi calling symbol with BT and Three logos

Three's WiFi calling is ultra flexible

Three inTouch WiFi calling scheme

How it works

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Regular mobile calls on Three are broadcast on their 3G signal. The frequencies Three (and BT) use for 3G are slightly less optimal for getting indoors than other networks, so they use extra technology to help out.

Three's WiFi calling lets your phone tap into their network via WiFi to make/take calls and send/receive SMS texts. Their 4G calling (VoLTE) improves calls coverage too by having more signal to tap into.

In our guide to WiFi calling, we rank Three as having the best scheme, because it supports a huge range of phones and it comes as standard on all Three's plans, pay monthly or pay as you go.

Unlike some providers, we found Android test phones not bought from Three worked with their WiFi calling, even if Three themselves are uncommital about offically saying they support them.

Useful link: Three's full guide to their WiFi calling scheme

BT Mobile's WiFi calling has improved massively

BT WiFi calling

See supported phones

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The good news is that BT Mobile also have WiFi calling and 4G calling on their network, so if you take a phone contract with them for a model that has the feature, you'll be able to use their scheme automatically.

Their see list of supported devices here has grown massively to cover almost every popular Android and iPhone model, so it's a lot easier to join BT on SIM only now and get the feature.

Even though BT officially say you need to have bought your Android phone from them originally to guarantee it'll work, our tests with non-BT bought phones worked fine too.

Like Three, you can also use WiFi calling for regular SMS text messages on BT Mobile (not all networks' schemes support this). It's handy in the age of SMS verifications, even if you never send texts yourself.

Useful link: Check supported devices at

Our verdict on this WiFi calling:

Minor win for Three

"Now that BT have sorted out compatibility issues they had with some models, there's basically little to split the two for WiFi calling. If your phone's supported, both are good options."

Compare pricing and deals

Free hotspot access on Three and BT Mobile

We compare what free WiFi each provider offers

WiFi symbol with BT and Three logos

BT Mobile customers can use BT's massive WiFi network

BT WiFi app with a hotspot map

See hotspot locations

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A good mobile network goes beyond just offering data via the traditional 4G and 3G transmitters. Quite a few of them have WiFi networks their customers can use to get online for free without using up your data.

BT Mobile are the best for this. If you're a phone contract customer or have one of their SIM only plans, you can download the BT WiFi app and get access to 5 million free hotspots nationwide.

The hotspots are located in busy places where you might be competing for mobile signal, or where it might struggle to get. You'll find them in airports, stations, high streets and restuarants and bars.

Sign in on the app once, and it'll automatically connect you to a hotspot when it's in range. Although our user tests found this can get annoying if you're only just in range and staying on 4G would be faster.

Useful link: More about free WiFi on BT Mobile

Three only have free WiFi on London Undergound

Three WiFi on the Underground banner

How to access it

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Customers on Three can't tap into a large nationwide network of free WiFi hotspots like you can on BT Mobile. But Three do offer something you don't get on BT: free WiFi on the London Underground.

All Three customers, whether you're pay monthly or pay as you go, can sign into the free WiFi on the TFL network with their Three details once, and then be automatically re-connected in future.

There's only WiFi on the platforms themselves. Once you're in the tunnels, it stops working. But given that mobile signal never gets underground, it's definitely a bonus.

There's also so much free WiFi about nowadays, you might find that not having it on Three is something you can very comfortably live with.

Useful link: Get free WiFi on the TFL network via Three

Our verdict on free hotspots:

A win for BT Mobile

"Users in and outside of London are more likely to find BT's network of 5 million free hotspots useful for saving data. Regular TFL users will find Three useful though. The small your plan, the more useful free WiFi is."

Compare pricing and deals

Which offers the better perks and extras?

Inclusive roaming on Three and BT Mobile

Which has the better roaming scheme?

Globe with BT and Three logos

Three offer way more inclusive roaming countries

Three Go Roam banner

See all countries

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Three’s long-standing unique selling point has been their free roaming abroad in selected countries. It was previously called Feel At Home but it's now called “Go Roam”.

Unlike most other networks who only offer inclusive roaming within the EU as standard, all Three's pay monthly SIMs and phones include a further 23 worldwide destinations listed here, including the USA.

In any of those places, minutes and texts back to the UK, and data for browsing will come out of your regular UK plan's allowance. There are some limits on how much data you can use while abroad (up to 19GB a month, depending on where you are).

We still rate Go Roam as the best inclusive roaming scheme of any UK mobile provider. And it certainly makes travelling outside the EU a lot cheaper than BT.

Useful link: Read Three's guide to Go Roam on their official site.

BT Mobile only offer inclusive EU roaming but it's 4G

BT's Roam Like Home banner

See countries list

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For quite a while now, all UK mobile networks have had to let you use your regular minutes, texts and data while you're abroad within the EU. BT Mobile are no exception:

BT Mobile call it "Roam Like Home" and it covers 47 European destinations across the continent (see the full list here), and you get it on every one of BT's SIM only plans and smartphone contracts as standard.

Compared to Three's Go Roaming, there are fewer destinations you can go free on BT and you're limited to Europe only. Everywhere else costs extra (see latest rates here).

But if you do most your travel in the EU or barely go abroad, BT Mobile roaming will be perfectly suitable. And you'll always get 4G speeds where available locally, which Three don't offer as standard.

Useful link: Learn more about Roam Like Home in BT's own full guide

Three now get you free upgrades when you fly with easyJet

Three's travel upgrades on easyJet

Get flight upgrades

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In the battle for who's the best network to go abroad with, Three have just launched a nice offer that adds a little cherry on top of their already top-rated roaming: free upgrades on easyJet.

All Three pay monthly customers (phone contract or SIM only) get free upgrades to easyJet's Hands Free service, which is all about making journeys through airports as smooth as possible.

It lets you check your hand baggage free, board just after Speedy Boarding passengers and pick up your baggage at the other end first. It normally costs £7 per single flight.

There are some limitations (our full guide here looks into these) like it only works from UK airports. But otherwise, it's a little nice extra that you get on top of all other Three benefits.

Useful link: Three's full guide to free easyJet upgrades

Our verdict on this topic:

A win for Three

"If you only ever go to EU countries, BT have the upper hand by offering 4G speeds wherever available. But if you go further afield, Three Go Roam could save you hundreds of pounds."

Compare pricing and deals

Free entertainment extras

Do Three or BT Mobile have the better freebies?

Streaming phone with Three and BT logos

Three give you unlimited streaming data with certain plans

Three's Go Binge scheme banner

See Go Binge benefits

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Video streaming is one of the things that uses up data the fastest on your phone. So what if a mobile network said that you could stream certain things and it wouldn't use up your data? Three now do this.

It's called Go Binge. And it comes with any pay monthly phone contract or SIM only deal with 12GB of data a month or more. It's so popular that other networks have started offering similar things (but not BT).

It doesn't cover every streaming app. But you can use Netflix, Apple Music and all these other streaming apps without it eating into your data allowance. And you can use it as much as you like in the UK.

If you're a regular streamer with the included apps, the data savings can be ridiculous. Streaming an hour of standard definition video could use around 1GB. Watch an hour a day and you're at 30GB of savings.

Useful link: Full details plus terms and conditions at

BT Mobile give away free BT Sport app access on some plans

BT Sport banner

Full offer terms

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There's no free data schemes on BT Mobile like Three's Go Binge, so you'll need to budget how much streaming you do into your choice of data plan.

If you join BT on phone contract or SIM only costing £15 a month (broadband customer price) or more and you'll get free access to the BT Sport app on your mobile.

The app lets you watch live sport covered by the BT Sport channel and has some extra features like news stories and video highlights.

Even though, you're restricted to watching only on your mobile and can't cast onto larger screens, it's a nice little freebie that some people will enjoy. Remember it will use your data though.

Useful link: How to get it when you join

Our verdict on entertainment extras:

Win for Three

"In terms of pure monetary value, getting free data for video streaming is worth more than a subscription to a watered-down version of BT Sport. But ultimately, the decision could boil down to what you're into."

Compare pricing and deals

Family plans compared on BT Mobile and Three

Which is best for taking out multiple contracts with?

A family plus BT and Three's logos

BT's Family SIMs give discounts the more deals you add

BT Mobile's Family SIM banner

Calculate discounts

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If you've got children old enough to have phones but not old enough to pay for it themselves, it's worth thinking about family mobile plans, which let take multiple deals on one account, with one bill.

BT Mobile's Family SIMs are a really good option for this. They let you add up to 4x extra SIMs on top of your main deal. And each extra SIM gets you a bigger discount (calculate savings here).

We like the fact that the extra SIMs are only on 30-day contracts, because it means you can add and drop them with practically no notice. That's good if you've all got different contract end dates currently.

The main limitation on them is that you all have to join on the same plan, with the same amount of data. We'd guess this is going to be unrealistic for loads of familes, because each person's usage will be different.

Useful link: Read our full review of BT's Family SIMs

Three offer discounts on phones and SIMs

Three existing customer offers screenshot

See customer deals

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One of the limitations with BT's Family SIMs is it only lets you add extra SIM only plans, not phone contracts. It's also hard to work out the savings up front. And everyone has to have the same amount of data.

Three are a little more flexible than that. If you already have a pay monthly phone or SIM from them, you can add extra phone contracts or SIM only plans to your account, at discounted rates (see prices per plan here).

Typically this only really boils down to the odd £1 a month off on SIM only plans. Or if you're after an extra phone contract, £1 to £2 a month and maybe the upfront cost waived too (see existing customer phone offers here).

The savings might not be as significant as BT's Family SIMs but you'll still get the benefit of managing extra deals from the same account. And even £12 a year isn't something to be sniffed at.

Useful link: See Three's existing customer offers

Our verdict on family plans:

A win for BT Mobile

"We welcome the fact that both networks have discounted deals for existing customers (it's rarer than you'd think). If you get the combo right, we think there's more money to be save with BT."

Compare pricing and deals

Which has the best deals?

SIM only: how BT Mobile and Three compare

Use our comparison tool below to see how BT Mobile and Three's similarly priced plans compare:

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Special offers on Three and BT Mobile

Here are the promotions currently running on both networks

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Phone contracts: BT Mobile vs Three

We look which network you're better off taking a smartphone from

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BT Mobile's phone contracts geared towards their broadband customers

Probably the most obvious reason to join BT Mobile on a phone contract is the pre-paid Mastercard you'll usually be able to claim with every phone, on practically every plan (see current values here).

If you haven't got BT broadband, you don't qualify for the £5 monthly discount, so you'd end up paying £120 more for exactly the same phone. Non-BT broadband customers will practically always find Three cheaper.

BT's phone contracts are on regular 24-month deals. There's no financing involved, nor early upgrade schemes to consider. Their upfront fees can be eye-watering sometimes too (over £200 on leading phones).

If you can jump on the right deal, with a reward card and a decent monthly price though, BT Mobile are as good a network as any to join on a phone contract.

Useful link: See current prices and range at

Three's phone contracts are on regular 24-month deals

Three's pay monthly phone range

See phone range

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You can get all of the perks and benefits we've mentioned earlier in this article on Three's phone contracts, which decently priced and on regular 24-month contracts (with no complicated financing arrangements).

On each phone, there tends to be one real killer plan that represents way better value than all the others. It's just a matter of looking for these at any one times.

All Three's phones are shipped unlocked but there aren't any specific early upgrade schemes like O2 Refresh or similar. You can buy yourself out of your contract but this is an expensive option.

Altogether, their added benefits, decent network speeds and reasonable prices make Three one of the more attractive providers to take a phone contract from.

Useful link: See phone range at

Our verdict on phone contracts:

Three normally cheaper for phones

"If we had to plump for either, we'd say it's Three who have the cheaper phone contracts generally, although it's worth seeing what you can get back from BT Mobile via their pre-paid Mastercard offers too."

Compare pricing and deals

Compare Three with other networks

Comparing Three and EE

Three vs EE

Read Three vs EE guide

Comparing Three and O2

Three vs O2

Read Three vs O2 guide

Comparing Three and Vodafone

Three vs Vodafone

Read our Three vs Vodafone guide

Comparing Three and giffgaff

Three vs giffgaff

Read Three vs giffgaff guide

Comparing Three and SMARTY

Three vs SMARTY

Read our Three vs SMARTY guide

Comparing Three and Virgin Mobile

Three vs Virgin Mobile

Read our Three vs Virgin Mobile guide

SIM Sherpa can help you find your next SIM only deal

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