Cookies on the SIM Sherpa website

We use cookies to track which pages on our website readers visit most. This helps us understand which topics people find interesting, to write more articles about them.

You can accept these tracking cookies or choose to block them. You can change these settings at any time.

X close

✖ Tracking cookies deleted and blocked

Ok, we will not track your page views as you move around any part of the SIM Sherpa website. But we will use that one cookie to remember you don't want to be tracked.

Click here to unblock tracking cookies

X close

✔ Cookies accepted

Thank you for accepting cookies for the SIM Sherpa website. This will help us constantly improve our content.

If you ever want to change your cookie settings for our website, go to our Cookies page here.

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

BT Mobile vs Three

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

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: 6th May 2021.

Deal notifications

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 have a bigger network that Three overall

Big Network Build lettering in Three brand

Read expansion plans

(opens in new window)

BT Mobile and Three use separate networks. BT use the EE network (they actually own the EE brand) and Three use their own. They have a couple of advantages and disadvantages over each other.

For calls and texts, there's not actually a huge difference nationally. Although, from our own experience we'd say you're much less likely to find outright blackspots on BT Mobile than Three. But this will vary by location.

The big advantage on BT Mobile is their 4G data coverage. They've got more of the country's physical landmass covered, so you're more likely to get a quality connection as you travel around.

In big cities and towns, the difference basically disappears. So a lot depends on where you live and use your phone. Definitely give their coverage checkers a go if you've not been on either network before.

Useful link: Three's 4G network expansion plans

5G is racing ahead on Three and BT Mobile

BT Mobile 5G explainer video screenshot

Watch 5G guide

(opens in new window)

Both Three and BT are suitable options if your current or next phone's 5G-ready - they both offer the faster technology with all their plans at no extra cost. But which network will you spend the most time on 5G with?

On a location-by-location basis, BT bring 5G to 160 towns and cities. While Three have got it in the 192 places listed here. On paper, that looks like advantage Three. But it's not quite that straightforward.

BT and EE are only reporting having 5G somewhere once they've got a signficant amount of that place covered with it - not just a few streets in the busiest parts of town like Three and other networks are doing.

So even though the reported number of locations may be higher, the coverage within those places could be much pooer. So check on a street-by-street basis using their network maps below to be sure.

Useful link: Our guide to the best 5G networks

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

(opens in new window)

BT Mobile's coverage map

BT Mobile coverage map screenshot

Check BT coverage

(opens in new window)

Our verdict on coverage:

Win for BT Mobile

"We'd say the overall blend of coverage on BT Mobile is better than Three. If you live and mostly stay in cities, you'd probably not notice the difference. But travelling around or living rurally, BT tend to be a safer bet."

Compare pricing and deals

Data 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

What BT say

(opens in new window)

Realistically, you'll spend the vast majority of your time on a 4G data connection rather than 5G on BT and Three. And independent testing has long pointed to BT's host network EE being the fastest.

Opensignal and Speedtest by Ookla put typical downloads over the EE network at 32.99 - 35.9 Mbps (like mid-range home fibre broadband). Three are slightly behind that on 21.60 Mbps (like a low-end fibre connection).

BT have also got rid of a 30 Mbps speed cap on their plans, which held you back. We'd say for browsing, the difference to Three will hardly be noticeable. But streaming and large downloads should be smoother on BT.

These are averages too. BT's network is capable of much higher peak speeds over 4G+ in urban centres than Three. In our experience, Three rarely go over double the typical speed. While on BT it can be 3 or 4 times.

Useful link: Read our BT Mobile vs EE guide

Three's 5G likely to be faster for the time being

5G owned. We're building the fastest 5G network banner

Why they're faster

(opens in new window)

BT have the upper hand on Three for 4G but for 5G, early testing shows that Three have faster downloads on average. That's according to Speedtest's results in London.

While BT's host network EE measured in at an already-impressive 140.16 Mbps (peaking at 245.73 Mbps, Three's typical downloads were 191.50 Mbps (peaking at 362.46 Mbps) - thrashing even fibre broadband.

Three say they're building the fastest 5G network, thanks to the fact that they've secured more radio spectrum in the same optimum range to deliver the potential of 5G (read Three's full explanation here).

As more spectrum is released for 5G, this advantange may change. And it's worth thinking about how often you'll be on 5G on both networks. But for raw speed where they have 5G, Three are current winners.

Useful link: Next steps in Three's 5G rollout

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

(opens in new window)

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

(opens in new window)

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

(opens in new window)

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

(opens in new window)

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's roaming has now been made much worse

Expired stampThree Go Roam banner

Read statement

(opens in new window)

Mobile networks have been removing EU roaming left, right and centre recently and sadly Three have now joined them, despite once having our best-rated roaming scheme of any provider.

Instead of getting inclusive roaming in 71 worldwide countries as before, customers who join Three from 1st October 2021 will pay a daily charge to use their allowances abroad (existing customers are unaffected).

That daily charge varies between £2 a day in the EU and £5 outside the EU, so will quickly add up, even on a week-long holiday - it’s all a bit disappointing really.

It also means, for EU roaming, you’re currently actually better off joining Three’s low-cost brand SMARTY, who still include EU roaming with each of their plans for now.

Useful link: Read Three's guide to roaming

BT Mobile still offer inclusive EU roaming

BT's Roam Like Home banner

See countries list

(opens in new window)

Three used to trump BT for roaming when they offered EU and worldwide roaming with each of their deals. But now BT win by default, because they still include EU on each of their plans.

No matter which deal you choose, you’ll be able to use your plan’s minutes, texts and data in EU countries without paying extra for usage (see the full list of destinations here).

There is a limit of 50GB data usage while you’re abroad each month, if your plan’s that big in the first place. If you do get through it, you’ll pay per MB at these rates.

For our real-life BT review, we find roaming on BT in the EU really good. It all works fine automatically. You get 4G wherever it’s available.

Useful link: Learn more about Roam Like Home

Our verdict on roaming:

A win for BT Mobile

"Most people will do most their roaming in the EU and BT still cover the cost of that as standard. Three don’t, so it’s a win here by default for BT."

Compare pricing and deals

Free entertainment extras

Do Three or BT Mobile have the better freebies?

Streaming phone with Three and BT logos

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

BT Sport banner

Full offer terms

(opens in new window)

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

Three have got rid of their free streaming data

Expired stampThree's Go Binge scheme banner

Read statement

(opens in new window)

You used to be able to get something called Go Binge included with any plan on Three over 12GB. But this has now sadly been ditched.

It gave you unlimited data to stream Netflix, Apple Music, Deezer, TV Player and for Snapchat. So even if your plan had a fixed data limit, you could do as much of that as you wanted.

A few networks still offer something similar to Go Binge (BT aren't one of them). It's a bit of a shame, because after roaming, Three are now looking a bit like a low-frills provider.

Useful link: Full details plus terms and conditions at

Our verdict on entertainment extras:

Win for BT

"Now Three have got rid of Go Binge, only BT have anything to offer in this department so win by default."

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

(opens in new window)

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

(opens in new window)

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:

BT Mobile and Three logos with a SIM card



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


Data: (0MB+)

Minutes: (0+)


Maximum length: (Any)

Added features

Special offers on Three and BT Mobile

Here are the promotions currently running on both networks

Special offer ribbon with BT and Three logos

Phone contracts: BT Mobile vs Three

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

Smartphone icon with Three and BT logos

BT and Three's phone contracts work similarly

Screehot of our phone comparison tool

Compare phone deals

(opens in new window)

The phone contracts on BT and Three are basically structured the same. They're what we'd call traditional deals: 24-month contracts where you pay for the phone and tariff in one payment (no financing or loans).

There's no early upgrade schemes on either. If you have BT broadband at home, you'll qualify for the £5 discount on BT's phone contracts. But realistically, we think very few non-BT customers will pay the extra £5.

Price-wise, we'd say Three tend to be the most competitive. You can join Three either directly or there are some third party retailers similar to Carphone Warehouse (but not them) that sell Three contracts. See how they compare on price here.

You get all the pay monthly benefits we describe above on each network, so choose your favourite from them to help you decide. And use our price comparison tool on the link below to see how BT and Three stack up for each model.

Useful link: Compare phone contracts with us

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'll depend on offers and prices for the specific model you want."

Compare pricing and deals

Other BT Mobile guides

Other Three guides