BT Mobile vs Sky Mobile: how the two's networks compare

✔ Sky Mobile have superior call signal, BT superior 4G data

Both BT and Sky Mobile piggyback off other networks rather than operating their own. Sky use the O2 network and BT use EE’s network for signal. Each has their pros and cons.

Sky Mobile have more of the UK’s physical landmass covered for call signal (2G/3G) and broadcast their signals on frequencies that are better for getting through building materials than BT.

However, BT Mobile are much better at covering the UK’s physical landmass for 4G, as well as covering more areas where people live. They’re definitely the best network for 4G coverage.

If you live in an urban area you probably won’t notice much of a difference for coverage. But you’ll generally get better 4G coverage as you move around on BT. Use their network maps to see how signal is in your local area.

Useful link: More about Sky's network

✔ BT have better 5G coverage than Sky

Looking at the number of locations covered by 5G between the two networks you might think Sky are the better network for 5G coverage. Sky currently cover 190+ UK towns and cities, while BT cover 160+ locations.

But this doesn’t tell the whole story. While Sky will declare a location covered when 5G is available in only a few small areas, BT will only claim that a location is covered once 5G is available in 50% of that location’s area.

That means BT Mobile tend to have better 5G coverage than Sky within their declared locations and also that they potentially cover far more locations than they claim, maybe even more than Sky.

In any case, if one network covers your local area while the other doesn’t then the national picture is less important. Use their coverage checkers to see which network has the best 5G coverage in your area.

Useful link: Check BT’s coverage in your area

✔ BT Mobile have faster 4G and 5G speeds

You’ll be on 4G most of the time with either network, so it’s important to know which gives the best speeds. Opensignal measure average speeds on BT’s hosts at around 44.0 Mbps against 17.1 Mbps on Sky’s.

That makes BT more than twice as fast as Sky for 4G on average. The difference is noticeable when you’re streaming HD video or downloading a large file, but for typical internet browsing it shouldn’t make a difference.

The two are a bit closer for 5G speeds. Opensignal and Speedtest by Ookla put typical 5G speeds on Sky between 110.9 Mbps - 127.97 Mbps against BT’s 131.9 Mbps - 158.30 Mbps. Still, BT come out on top.

It’s important to note that Speedtest’s results show slower speeds on Sky than their last report and faster speeds on BT. This is likely because more speed data is becoming available for 5G, so we're getting a better impression of what each network is capable of.

Useful link: BT’s guide to their 5G

✔ BT have one of the best WiFi calling schemes

Since BT Mobile don’t broadcast their call signal (2G/3G) on ideal frequencies for getting through building materials, it’s important that they provide a good WiFi calling scheme to avoid indoor blackspots.

WiFi calling lets your phone connect to calls using WiFi signal instead of call signal, and 4G calling does the same for 4G. BT offer both and they let you move from WiFi signal to 4G without your call dropping.

You can also send texts over WiFi and 4G on BT, and their brilliant 4G coverage and WiFi hotspot provision means you can make the most of either feature.

They don’t claim to cover Android models not bought directly from them. But the manufacturer-bought Android model we tested worked fine, so we think they’re being defensive in their list of supported devices.

Useful link: Our list of the best WiFi calling networks

✔ Sky’s WiFi calling not supported on a lot of phone models

Sky’s WiFi calling isn’t quite as good as BT’s. While Sky offer both WiFi and 4G calling, we couldn’t switch from WiFi to 4G without our call dropping, unlike on BT where it transferred over smoothly.

You also can’t send or receive text messages over WiFi or 4G, so if you don’t have call signal you won’t be able to text at all.

Also their list of supported devices is pretty short. While most iPhone models should work, even ones not bought from Sky directly, Android users might struggle with getting WiFi calling to work on Sky.

So, it’s not nearly as good a feature as BT’s WiFi calling and it’s harder to get it working in the first place. But if you get poor indoor coverage on Sky, it’s good enough so long as your WiFi is decent.

Useful link: Sky Mobile's WiFi calling help guide

✔ BT offer a huge network of WiFi hotspots

We like it when a network offers free WiFi hotspots, as it’s a great way of saving data while you’re on the go. It means you can safely take a smaller (cheaper) data plan if you’re in an area with a lot of free WiFi.

And that’s exactly what BT Mobile provide. They offer the largest number of hotspots of any network, with 5 million+ hotspots all over the UK. It’s our favourite WiFi hotspot scheme and you get it on any of their pay monthly plans.

You’ll usually find these hotspots in popular areas, such as in restaurants, transport hubs, shopping centres and even residential areas. There’s no limit to have much WiFi you can use and it’s usually pretty fast.

While their app is great for automatically logging you into your nearest hotspot, this can sometimes get you slower speeds than just being on 4G. But other than that, it’s a brilliant scheme.

Useful link: More about free WiFi on BT Mobile

✔ BT and Sky both have some free WiFi hotspot access

Sky also offer a decent network of WiFi hotspots, with 20,000+ available around the UK. But there’s one key thing to know with Sky’s feature. It’s free for everyone anyway.

There’s no exclusive benefit for Sky Mobile customers, so it can’t be really be considered a specific incentive for joining Sky Mobile. The only benefit is you can use your existing details to log in to a hotspot.

It’s a pretty good network of hotspots. The WiFi is fast and covers a lot of areas. It’s nowhere near as widespread as BT’s, and Sky Mobile don’t provide WiFi on the Underground either (neither do BT).

If Sky brought out an exclusive benefit for their customers, like making some hotspots exclusive or adding an automatic login feature, then their scheme would be a lot better.

Useful link: Costs for going over your limit on Sky

✔ BT Mobile offer free EU roaming on all plans

BT’s EU roaming scheme hasn’t changed at all, even though their host EE have got rid of theirs. You still get inclusive roaming in these 46 EU destinations on any BT plan.

While you’re abroad they do limit you to 50GB if your data allowance is over that amount. But that’s more than enough for short trips, unless you’re doing something very data-heavy on your phone.

For going beyond the EU, BT do offer some data add-ons that are charged at a daily rate. At the time of writing these give you 500MB a day for £6 a day in 12 worldwide destinations. For other destinations you’ll have to pay as you go at these rates.

In our real-life review of BT we found their EU roaming to work well. They’re one of the best for EU roaming, even if they’re not an amazing choice for worldwide roaming.

Useful link: Learn more about Roam Like Home

✔ Sky’s roaming scheme is changing soon

Sky Mobile used to be at the top of our rankings for the best roaming networks. But they’ve recently announced they will be changing their roaming scheme and this will have a big effect for EU travellers.

From May 3rd 2022, Sky Mobile customers will no longer get free EU roaming as standard. Instead, you’ll have to pay a daily rate of £2 a day while abroad in their EU destinations.

This change has a silver lining, as roaming beyond the EU in their covered worldwide destinations will cost the same as roaming in the EU. This will make Sky by far the cheapest network for worldwide roaming.

But we consider EU roaming to be more important, so we see this change as an overall negative. You’ll still be able to use your whole data allowance, which is nice. But the lack of free EU roaming will seriously hurt Sky.

Useful link: Full roaming costs per country on Sky

✔ Sky TV customers can stream Sky apps without using data

If you have a Sky TV home package, Sky Mobile’s Watch benefit can help you make the most of it. It lets you stream Sky’s TV apps on your phone while you’re on the go without using up your data.

When you stream these apps on the go, the data you would have used won’t come out of your monthly allowance. That can add up to a massive amount of data saved, as streaming can usually eat up your data quickly.

What makes this even better is that every Sky pay monthly plan comes with this benefit, even the cheapest plan. If you know you’ll only stream Sky’s apps, then taking their smallest data plan is a good idea:

BT don’t offer anything nearly as generous. But there are a couple drawbacks. Ads will come out of your allowance and you need to have some data leftover (50MB) for it to work. But otherwise, it’s a brilliant benefit.

Useful link: What the Sky Go app can do

✔ BT give broadband customers £5 off a month

It can be convenient to go with the same company for your mobile and broadband deals as it’s easy to manage all your payments in one place. BT add to this by offering a unique discount for broadband customers:

BT customers get a flat £5 a month discount on all SIM only and phone contracts, usually making them much better value than their hosts EE.

Be aware that BT often try to hike up the cost of your broadband deal once your contract for it is over. You only get the discount on your mobile plan if you keep on your broadband deal, if you cancel it you lose your discount.

So it’s a way for them to keep you loyal. But if you don’t have any issue with that and you’ve got a good broadband deal, then it’s a decent reason for joining BT Mobile. But we think Sky offer a little more to their TV customers.

Useful link: BT broadband customer? See your exclusive deals here

✔ BT give you bigger discounts the more Family SIMs you add

We really like it when a network gives discounts on additional SIMs added onto your main account as it’s a great way for parents to save money while getting their kids onto their own mobile deals. BT offer a great Family plan scheme.

You can add up to 4x extra SIMs onto your account, with a bigger discount being applied to your monthly bill for each SIM added (calculate savings here).

Add to this the fact they’re all on 30-day contracts and you’ve got great savings and decent flexibility. You can add and drop them when you want, so you don’t have to wait until everyone’s contracts are up.

The major drawback is that all the SIMs have to be the same data amount as the plan that the main account holder has. That takes a lot of the flexibility away and isn’t really realistic for most families. Still, it’s a useful scheme.

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

✔ Free BT Sport app access on pricier plans

If you want to watch BT Sport’s output without having to buy the TV channel, you can take one of BT’s higher-end plans that offer free access to the BT Sport app on your phone.

By taking a SIM only plan or smartphone contract worth £15 or over (even after the broadband customer discount is applied) you get free access to BT Sport on your phone as long as your contract lasts.

Qualifying SIM only plans

You can watch any BT Sports channel on the app, as well as news and highlights on the go. The downside is you can only watch it on your phone and you can’t cast it to a TV or watch it on a laptop.

And you don’t get free streaming data like you do on Sky, nor do BT offer unlimited data deals. So you’re not getting as much as you would on Sky, but it’s still a nice benefit.

Useful link: How free BT Sport app with BT Mobile works

✔ Sky Mobile let you bank up unused data

Data rollover is a nice feature to have on a mobile network. It means the data you don’t use up by the end of the month will be added to your next month’s allowance. It helps you get the most out of your deal.

We think Sky’s piggybank benefit is the best data rollover feature of all networks. You can keep data for up to 3 years and withdraw it whenever you need it in 1GB increments.

You get it on any pay monthly plan for free and it works automatically. The only thing you have to do manually is withdraw data. You can share data with other users on your account or even trade it in for discounts on phones and tablets.

It’s great that they give you something to do with your data if you bank up more than you’ll ever use. BT don’t offer data rollover at all.

Useful link: Sky's full guide to their Piggybank system

✔ Sky offer much more flexibility

Sky base their phone contracts on credit agreements (essentially loans) where you’ll pay off the cost of your phone over either a 24-month or 36-month contract, with your usage (mins, texts, data) as a separate payment.

This means you can cancel your usage plan whenever, you can pay off the cost of your phone early and you get flexibility in how long you want your contract to be. You can also trade your phone in to upgrade early if you want.

BT on the other hand only offer traditional 24-month contracts, where the cost of your phone and usage are one single payment. You can’t change your usage plan or pay off your loan early with them.

Also, BT seem to only offer a small range of phones while publishing EE phone deals on their website more prominently. Since BT own EE, we think they’re phasing out their own phone deals in favour of EE’s.

Useful link: Use our phone deal comparison tool