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Sky Mobile vs O2:
key differences between the 4G/5G networks

O2 and Sky Mobile logos and Vs letters

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Both Sky Mobile and O2 use the same network, so we check if there are any coverage or speed differences and compare their other benefits head-to-head. Last updated: 28th March 2023.

In our O2 vs Sky Mobile guide

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Sky Mobile vs O2 networks

Are there differences in signal between Sky Mobile and O2?

We did some tests using a Sky and O2 SIM to find out

Signal bars with Sky and O2 logos

You get identical signal on Sky Mobile and O2

Sky Mobile and Telefonica deal screenshot

See the claim

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

While Sky isn’t owned by O2, they do use O2’s network for calling and data signal. They signed a long-term deal to use them in future too, so this isn’t something that will change anytime soon.

Sky customers get identical signal to being on O2 directly. They offer 5G/4G/3G/2G in the same areas you’d get them on O2 and signal strength is identical between the two networks.

This is good for Sky, as O2 have the joint-largest percentage of the UK’s physical landmass covered for call signal (2G/3G) and they provide 4G in 98% of the places where people live.

Even so, we’d still recommend checking either networks’ coverage checkers below to test signal away from where you live. Use it to check everywhere you’re expecting to use your phone, not just at home.

Useful link: Which network has the best indoor signal?

Sky also get full access to O2’s 5G network

Sky Mobile 5G banner

How to get it

at Sky.com
(opens in new window)

If you’ve got a phone that supports 5G, then you’ll get access to O2’s growing 5G network on Sky in the same areas as being on O2 directly.

Last time we checked, Sky didn’t claim to have 5G live in the same 750+ UK towns and cities as O2. But we think this is due to them being slower to update their website rather than a sign of any actual difference.

5G comes as standard on all plans, both on O2 and Sky. You have to choose it as an add-on on Sky and with O2 you have to say that your phone is 5G ready at the checkout.

In general, 5G coverage in their locations is good and both networks’ coverage checkers matched up pretty well to reality in our tests. But we did have some trouble getting Sky’s 5G to work on some Android phones.

Useful link: O2 latest 5G rollout news

Use Sky or O2's coverage maps to check your local signal

Check signal everywhere you'll use your phone, not just at home

Sky coverage checker

Sky's coverage map

Check Sky signal

using their official map
(opens in new window)

O2 coverage checker

O2's coverage map

Check O2 signal

using their official map
(opens in new window)

Our verdict on coverage:

No current winner

“Sky use the same masts as O2 and as such offer identical coverage. Further down the page we go into the differences in pricing and the benefits that either network offer.”

Compare pricing and deals

Data speeds: are they also identical?

Do you get slower speeds on Sky Mobile vs O2 directly?

Speedometer with Sky and O2 logos

We found 4G data speeds the same on O2 and Sky


What O2 say

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

Despite some Sky users questioning if Sky Mobile offer the same 4G speeds as being on O2 directly, we’ve never found any evidence of a speed cap or differences in speeds when we’ve tested them ourselves head-to-head.

You can expect same typical 4G speeds of 16.8 Mbps according to the latest report from independent network testers Opensignal. That does mean Sky use the slowest of all UK networks for 4G.

In our tests we managed to get speeds up to 95 Mbps over 4G in the city centre, but speeds in rural areas crawled down to 5 Mbps. So we can see how Opensignal get their result.

Overall, both networks are fast enough for your average browsing and social media needs and even streaming HD should be quite smooth. But you’ll still notice things loading a bit slower than on other networks.

Useful link: More about O2's 4G

5G speeds are also identical on both networks

O2 5G launch banner

5G rollout latest

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

Just like with 4G, Sky get access to the same 5G speeds as their hosts O2. To see what typical 5G speeds look like on each network we use results from independent network testers Opensignal and Speedtest by Ookla.

According to their latest reports you get typical 5G speeds between 80.57 Mbps - 92.3 Mbps. You’ll get peak speeds up to 214.2 Mbps. Overall that makes them the slowest network for 5G.

It’s a bit of a let down considering how good their 5G coverage is. In any case it’s a big improvement over their 4G speeds and fast enough to download a HD movie in seconds.

If you’re a mobile gamer or file sharer then you might prefer to join a faster network for 5G (read our guide here) but both O2 and Sky are good enough for the typical phone user.

Useful link: Sky Mobile’s 5G phone range

Our verdict on speeds:

An even draw

"We’ve never found any differences in speeds between the two networks, but neither are the best choice for 4G or 5G speeds. In any case, your choice between them will come down to the different prices and benefits they offer."

Compare pricing and deals

Other network technology on Sky Mobile and O2

What else do either network offer to keep you connected?

Gears icon with O2 and Sky logos

O2 include WiFi/4G calling and WiFi hotspots

O2 WiFi and 4G calling banner

See supported phones

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

O2 already broadcast their call signal (3G/2G) on frequencies that are good at getting through building materials. However, you can still run into indoor blackspots, which is where WiFi and 4G calling come in handy.

Both networks have WiFi calling, which lets your phone use WiFi to connect to calls instead of conventional call signal, and 4G calling which does the same for 4G. These are standard on all plans.

However you might run into issues getting O2’s WiFi calling to work as many Android models aren’t supported (see full list here). And Pay As You Go customers can’t use either feature.

But if it works, it’s a great feature. It’s also backed up by O2’s great network of 15,000+ free WiFi hotspots to keep you connected wherever you go (even on the London Underground).

Useful link: O2's guide to all their network features

Sky Mobile also include WiFi/4G calling and WiFi hotspots

Sky Mobile WiFi calling

See supported phones

at Sky.com
(opens in new window)

Sky also include WiFi and 4G calling features on all of their pay monthly contracts. Most iPhone models are supported, but you may run into issues getting WiFi calling to work on some Android models.

If you didn’t get your Android model from Sky then there’s no guarantee it will work. The Android model we bought from the manufacturer didn’t work with Sky’s WiFi calling.

And Sky’s list of supported models is a bit shorter than O2’s. So even if you got your phone from Sky directly you might not be able to get WiFi calling to work.

Sky also have a network of free WiFi hotspots, but anyone can connect to these, not just Sky Mobile users. And there’s no free WiFi on London’s TFL network like there is on O2.

Useful link: Full help guide on Sky's WiFi calling

Our verdict on network features:

Minor win for O2

“It’s easier to get WiFi calling working on different phone models on O2 and they have a better WiFi hotspot scheme that is an exclusive benefit for joining their network. So O2 take this one.”

Compare pricing and deals

O2 vs Sky Mobile benefits

Unlimited streaming data: Sky Mobile vs O2

Which networks let you stream without eating into your data allowance?

Play video symbol on phone with Sky and O2 logos

Free data streaming on Sky’s TV apps as standard

Unlimited streaming with a tablet and phone

See all features

at Sky.com
(opens in new window)

In our eyes the best benefit of joining Sky Mobile is the unlimited streaming data for their TV apps you get on all their plans at no extra cost. When you stream these apps on data it won’t eat into your allowance.

This can save you a lot of data. Streaming for one hour can use up about 1GB of data, but with this benefit you can keep up with all your favourite shows on the go without having to worry about your data usage.

Not only is the benefit great in itself, but it’s also included on every single one of Sky’s plans, even their cheapest one which still lets you stream as much as you like on Sky’s TV apps:

It’s a great way to pass the time on long journeys and it feels incredibly liberating to not be restricted. It also means you’re getting the most out of your home TV package.

Useful link: Sky's full guide to free streaming data

No streaming data on O2 but they do have unlimited

O2 Limitless data banner

Read full terms

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

O2 offer nothing like Sky’s free streaming data (read our guide to the best free social media and streaming data schemes here). You can get an unlimited data plan, however.

You can either choose one of their top-end model phone contracts, or choose one of their unlimited data SIMs:

Sky don’t offer unlimited data at all. On the one hand unlimited data plans are more flexible as you can do what you like without running out of data, but on the other hand it’s much more expensive.

Useful link: O2's guide to their unlimited data tariffs

Our verdict on streaming data:

Easy win for Sky Mobile

"Sky Mobile’s data streaming benefit is one of the best of all networks and can save you a lot of data each month. O2 offer nothing similar, so an easy win for Sky Mobile here."

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Roaming compared on Sky Mobile and O2

Do both networks still let you use your SIM abroad at no extra cost?

O2 and Sky logos with a globe

O2 include EU roaming and some worldwide roaming

O2 free EU roaming banner

Read roaming guide

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

O2 are the only main UK network to still let you roam in the EU at no extra cost. On all their plans you can use up to 25GB of your UK allowance in these 49 EU destinations.

Along with this, O2 offer bundles of minutes, texts and data for roaming in 27 worldwide destinations as an optional extra on their pricier plans (you only get one extra) or to be purchased at any time (see latest costs here).

You get a small allowance of 120 mins, 120 texts and 150MB of full speed data to use in their worldwide destinations. If you get through that data you’ll actually get unlimited data but only at sub-2G speeds.

O2 aren’t the winners of our best mobile network for roaming rankings, but they are a good network for short trips both to the continent and beyond.

Useful link: All other roaming costs on O2

Sky no longer offer inclusive EU roaming

Sky Mobile roaming passport banner

See costs & countries

at Sky.com
(opens in new window)

Sky used to actually be better than O2 for EU roaming, but they got rid of their inclusive EU roaming scheme a while ago. That means O2 essentially win by default here.

You have to pay £2 a day to roam in all of Sky’s covered EU destinations. There are no roaming passes or any way around this and it can add up if you’re on a long trip.

At the very least they still don’t restrict how much of your data allowance you can use while abroad. This is one advantage Sky have over O2, but we don’t think it makes up for the extra cost.

It’s worth noting that roaming beyond the EU (see countries here) is also charged at the same £2 daily rate. That makes Sky a decent value choice for going beyond the EU compared to some other networks.

Still, we think more people care about EU roaming. And for that, Sky Mobile have got much worse.

Useful link: Sky's full guide to roaming on their network

Our verdict on roaming:

Win for O2

"More users will need EU roaming and for that O2 are the much better choice. For going beyond the EU we think most customers can be happy with either network. So O2 ultimately take this one."

Compare pricing and deals

Data rollover on O2 vs Sky Mobile

Both networks have schemes to help you hold onto your unused data. But which is better?

Repeat symbol arrows with Sky and O2 logos

Hold onto leftover data for up to 3 years on Sky

Sky Piggybank banner

How it works

at Sky.com
(opens in new window)

No matter what plan you take with Sky, you’ll get what they call a “piggybank” for your unused data. Any data you haven’t used at the end of the month will go into this piggybank for later use.

Think of it like a savings account for your data. If you ever run out of data you can take some from your piggybank in 1GB increments to prevent yourself incurring extra data charges.

And you can even share data in your piggybank with other users on your account. If one user uses up their data you can gift some to them. Or you can trade unused to get discounts on devices.

Of all the data rollover schemes in the UK, Sky’s is our favourite. It lets you keep your data for three years and use it as you please. No other network offers that sort of flexibility.

Useful link: Sky's help article about data rollover

O2 only include data rollover on Pay As You Go

O2 data rollover

See qualifying plans

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

Unfortunately, O2 don’t offer data rollover on any of their pay monthly plans. But if you have to buy data add-ons at any point then they let you keep that add-on for later use.

You can get data rollover on O2’s Pay As You Go “Big Bundles”. These give you a bundle of mins, texts and data that you pay for up front each month.

Make sure to renew your monthly bundle each month or else you’ll lose all the data you’ve rolled over. But if you keep renewing your bundle you can keep your leftover data for longer than most networks let you.

While there is a cap on how much you can rollover (usually equal to your bundle’s data amount) if you renew your plan on time you can keep your rolled over data for multiple months. It’s an alright scheme overall.

Useful link: See latest O2 Big Bundle prices

Our verdict on data rollover:

Win for Sky Mobile

“While O2’s scheme is good for what it is, it’s only included on their worse value PAYG bundles. Sky offer a more flexible scheme on all of their plans. An easy win for Sky here.”

Compare pricing and deals

Prices and plans compared

O2 and Sky Mobile special offers

Here's what's currently running on the two networks

Special offer tag with O2 and Sky logos

SIM only deals on O2 vs Sky Mobile

Which network has the best value plans?

Mobile SIM card with O2 and Sky logos



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Phone contracts on Sky Mobile vs O2

Do O2 or Sky Mobile have better smartphone deals?

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O2 offer great flexibility on their phone contracts

O2 custom plans

Read why

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

O2 offer most of their phone deals on what they call “Refresh” contracts. These split the cost of your device and your usage plan (mins, texts and data) into separate bills that make your monthly payment.

This lets you pay off the cost of your phone and end your contract early if you want to upgrade. It also means you can change your usage plan whenever you want if you feel like you’re paying too much.

They also offer great flexibility with their Custom Plans. This lets you set your upfront cost as you like it, and choose a contract length between 3 and 36 months which will change how much you pay each month.

The actual cost of your device stays the same through your contract. However, if you’ve missed any payments in the past it might be difficult to pass a credit check, as O2 need to be sure you can pay them back.

Useful link: Read O2's guide to their Custom Plans

Sky also offer flexible phone deals based on finance

Sky Mobile Swap

How Swap works

at Sky.com
(opens in new window)

Sky’s phone contracts work similarly to O2’s. They’re based on finance, with one payment for your usage and another for the cost of the phone. But you can only choose from two contract lengths: 24 or 36 months.

Taking a 24-month contract means you’ll pay more per month, but less over the length of your contract. This is because Sky are one of only a few networks to make you pay more over a 36-month contract.

They also have a unique Swap benefit on phones. This scheme lets you "upgrade for free" after 12 months on Swap12 (24-month contract) or 24 months on Swap24 (36-month contract).

We’re not big fans of this scheme though. What’s the point of handing in your phone to upgrade early when you could get better value selling it somewhere else, especially when you’ve already paid half of the cost.

Useful link: Full ins and outs of Sky's Swap

Our verdict on phone contracts:

Win for Sky Mobile

“Sky get you better value deals while also including all the benefits we mentioned above. While O2 offer better flexibility, we imagine more people will care about Sky’s value. In any case, use our phone comparison tool to find the best deal.”

Compare pricing and deals

Other Sky Mobile guides

More articles about O2

Other mobile network reviews

Networks ranked by benefits