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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: 24th January 2022.

In our O2 vs Sky Mobile guide

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Sky Mobile vs O2 networks

Are there coverage differences between Sky Mobile and O2?

We tested both networks to find out

Signal bars with Sky and O2 logos

Coverage is identical on Sky Mobile and O2

Sky Mobile and Telefonica deal screenshot

See the claim

(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 Mobile customers get the same network coverage experience as being on O2 directly. The places where you’d get 5G/4G/3G/2G on O2 are the same places you’d get them on O2 and with the same signal strength.

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 shares the same 5G network as O2

Sky Mobile 5G banner

How to get it

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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.

You might see that Sky don’t report the same number of locations as O2 on their website, but we think this is just because they’re a bit slower to update their list, rather than a genuine 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 our real life tests we found both networks’ coverage checkers to be pretty accurate. 5G is still on a street by street basis. We did have a bit more trouble getting Sky’s 5G to work on certain Android models, however.

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

"Both networks use the same masts and have the same coverage. There’s nothing to compare here, so things like prices and benefits are much more important."

Compare pricing and deals

Data speeds: are they the same?

Is Sky Mobile slower than being on O2 directly?

Speedometer with Sky and O2 logos

We found 4G/5G speeds the same on Sky as on O2

O2 5G launch banner

5G rollout latest

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Since we found no evidence of a cap on Sky, speeds will be the same on both. Independent network testers Opensignal have put O2 as the slowest UK network for 4G speeds with average speeds of 17.1 Mbps.

If you test speeds on O2 directly against other networks (not on O2’s network) you’ll notice HD videos loading a little bit slower and files will take a big longer to download. It’s enough to be noticeable.

As more and more tests are being done by Opensignal and Speedtest by Ookla, we can see average 5G speeds lie somewhere between 110.9 Mbps and 127.97 Mbps. They’re not the fastest, but that’s still pretty fast.

That will let you game, stream and share files very comfortably. Speeds can suffer further away from the mast, however.

Useful link: More about O2's 4G

Our verdict on speeds:

An even draw

"We found no evidence of a speed cap from our testing the networks against each other, so what you get on O2 you’ll get on Sky. Bear in mind neither are particularly fast, however."

Compare pricing and deals

Other network technology on O2 and Sky Mobile

How else do they keep you connected?

Gears icon with O2 and Sky logos

O2 have WiFi calling, 4G calling and free hotspots

O2 WiFi and 4G calling banner

See supported phones

(opens in new window)

O2 use mobile signal frequencies that are great for getting into buildings to make calls. But it’s still important for a network to have good WiFi and 4G calling provisions to help where signal is poor.

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.

But one issue is whether O2 will support your phone in the first place, as support for Androids can be patchy. You also can’t send or receive texts over WiFi. Finally, 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 have WiFi calling and some free hotspots

Sky Mobile WiFi calling

See supported phones

(opens in new window)

Sky Mobile also offer WiFi calling and 4G calling on all of their pay monthly plans. But like O2 there’s quite a few compatibility issues with Android phones, however iPhones should work fine.

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.

Their list of supported devices is also more limited than O2’s. So your phone might not even be compatible with Sky’s WiFi calling even if you buy it from them directly.

Sky do have a great WiFi hotspot scheme, but anyone can connect to them, not just Sky Mobile customers. You also don’t get free WiFi on London's TFL network like you do on O2.

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

Our verdict on network features:

Minor win for O2

"O2’s network features are just a bit slicker than Sky’s. Not only do you have a better chance of your phone being supported for WiFi calling, but their hotspot scheme is also better. An overall win for O2 here."

Compare pricing and deals

O2 vs Sky Mobile benefits

Unlimited streaming data: O2 vs Sky Mobile

We look at what both providers offer

Play video symbol on phone with Sky and O2 logos

Stream Sky TV apps without using data

Unlimited streaming with a tablet and phone

See all features

(opens in new window)

Our favourite benefit of being a Sky Mobile customer is getting unlimited streaming data to watch Sky's TV apps on every one of their plans for free. The data you use to stream won’t come out of your monthly 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.

The fact that it’s offered on all of their plans is also incredibly generous. It even comes on their cheapest plan which you can use to stream as much as you want on their 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

O2 don’t offer any unlimited streaming options

O2 Limitless data banner

Read full terms

(opens in new window)

O2 don’t offer anything similar to Sky’s benefit (see our guide to all other networks with free data for streaming or social media schemes here). The only way to get anything similar is to get an unlimited data plan.

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

Sky actually don’t offer unlimited data at all. Unlimited data is more flexible as you can stream anything without running out of data, but it’s a lot more expensive. Still, it’s a difference worth considering.

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

Our verdict on streaming data:

Easy win for Sky Mobile

"To get the same sort of benefit as Sky Mobile on O2 you’d have to shell out a lot for an unlimited data plan. Few networks can even compete with Sky’s brilliant unlimited streaming data scheme."

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Roaming compared on O2 and Sky Mobile

Which gives you more inclusive roaming?

O2 and Sky logos with a globe

O2 offer worldwide inclusive roaming on premium plans

O2 free EU roaming banner

Read roaming guide

(opens in new window)

On every pay monthly phone and SIM only plan you’ll get inclusive roaming in these 49 EU countries as standard. They’re actually the only one of the major four networks to keep their roaming scheme in place.

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).

In those 27 destinations you’ll get a bundle of 120 minutes, 120 texts and 150MB of data at full speed. After using your full speed data, you’ll get unlimited data that’s severely speed capped.

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

You no longer get free EU roaming on Sky

Sky Mobile roaming passport banner

See costs & countries

(opens in new window)

It used to be a close call whether Sky or O2 were the better network for roaming, but since Sky have got rid of their free EU roaming they’ve essentially given O2 the win here.

On any Sky Mobile plan you’ll now have to pay a daily fee of £2 to roam in their EU destinations. There are no ways around it and it can get pretty pricey if you’re away for a long time.

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.

The only positive change to come from Sky’s change is that roaming in their worldwide destinations is much cheaper now (the same £2 a day rate). If you want to use your allowance beyond the EU, Sky might be the better option of the two.

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

"O2 are now the much better choice for EU roaming. Sky’s changes do make them much better for worldwide roaming than before, and arguably better than O2. But we think more people care about EU roaming, so an easy win for O2 here."

Compare pricing and deals

Data rollover on Sky Mobile vs O2

Both networks have unused data schemes. Here are the differences.

Repeat symbol arrows with Sky and O2 logos

Sky Mobile let you keep unused data for three years

Sky Piggybank banner

How it works

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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.

It works just like a savings account. If you’ve run out of data one month you can withdraw data from the piggybank 1GB at a time to stop yourself incurring extra charges.

On top of that you can even share data with other users on the same account, so if one user runs out of data you can transfer some to them. You can also trade in your unused data for 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 offer data rollover on Pay As You Go

O2 data rollover

See qualifying plans

(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.

But O2 do offer data rollover on their pay as you go “Big Bundles”. These are bundles of minutes, texts and data that you pay for with the credit you top up your SIM with.

It sort of works out like a monthly deal as you have to remember to renew your plan every month, otherwise you’ll lose your rolled over data. But they do let you keep it for longer than most networks.

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 pretty good, their PAYG bundles are worse value than their pay monthly plans anyway. Sky’s scheme is the most flexible and user friendly of all networks, so O2 can hardly compete 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?

Smartphone with Sky and O2 logos

O2's phone contracts are very flexible

O2 custom plans

Read why

(opens in new window)

Most phone models on O2 are offered on what are called “Refresh” contracts that split the cost of paying back your phone and your usage (minutes, texts and data) into separate bills that are paid together.

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 anywhere between 3 and 36 months which will change how much you pay each month.

The total cost of the phone always stays the same. The only downside is that you might not be accepted for a phone deal if you have any blips in your credit history, as O2 have to be sure you can pay them back.

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

Sky's phone contracts are based on finance too

Sky Mobile Swap

How Swap works

(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.

If you choose a 24-month contract you’ll be paying more per month, but you’ll be paying less. Sky are one of the few networks that make you pay more overall for their longer 36-month contracts.

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).

But we don’t really like this scheme. Why surrender your phone for an early upgrade when you’d get more value selling your phone elsewhere? You’ve already paid for half of the phone, so why give it up?

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

Our verdict on phone contracts:

Win for Sky Mobile

"Sky Mobile are able to offer cheaper deals with all of the extra benefits mentioned above. We think more people will care about this than O2’s flexibility, but it’s still worth comparing 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