Sky Mobile vs O2: same masts, what's different?

Sky Mobile runs on O2's network, so a Sky SIM and an O2 SIM pick up the same masts in the same places. Sky isn't part of O2, though. It's a separate company that uses O2's network under a commercial agreement, and Ofcom lists Sky Mobile among the brands that "use O2's network". The differences are in price, how each handles price rises, what happens to unused data, and the extras and service you get.

How do Sky Mobile and O2 compare at a glance?

The table pulls prices and price rises from our live deal feed, so it matches the deals on our comparison pages today. The roaming, eSIM and exit-fee rows come from each network's own pages.

Is Sky Mobile cheaper than O2?

For the same data, usually yes. When we checked on 23 September 2026, Sky's cheapest unlimited data plan in our feed was £18 a month on a 12-month term. O2's cheapest was £23.99 a month on a 24-month term. Over each full contract, that's £216 with Sky against £630.76 with O2, because O2's price also rises twice during those two years.

Contract length is part of that gap. Every Sky SIM deal in our feed runs for 12 months. O2 sells 30-day, 12-month and 24-month SIMs, and its lowest monthly prices sit on the longest terms. Its 30-day unlimited plan was £38 a month when we checked, which buys freedom to leave at a month's notice.

If you want unlimited data and can commit for a year, Sky is the cheaper route in today's feed. If you might leave within months, O2's rolling plans cost more but carry no exit fee. Our data allowance guide helps you check whether you need unlimited at all.

Can the price go up during the contract?

Both can rise, but in very different ways. O2 publishes a fixed amount: "Each April, your airtime plan will increase by £2.50 for voice plans and 75p for data-only and smartwatch plans". You see those rises before you sign. On the £23.99 deal above, that means £26.49 from April 2027 and £28.99 from April 2028.

Sky doesn't schedule rises. Instead, its plans page says the "data plan price may change during the 12-month minimum term", with no amount or date attached. Because nothing is agreed up front, a Sky rise comes with 30 days' notice and the right to leave without penalty, as our price rise guide explains.

So the trade-off is certainty against exposure. With O2 you can work out the full cost of your contract on day one. With Sky you can't, but any rise is capped by a shorter term and gives you a way out.

What happens to data you don't use?

This is one of the clearest differences between the two. Sky's plans page promises you can "roll your spare data for up to a year", and says spare data can also be used "on a range of rewards". It applies to Sky's capped data plans, so light users build up a buffer over time.

O2's rollover is narrower. It applies only to its Plus and Ultimate pay monthly plans, and unused data carries over for one billing cycle. Unlimited plans don't need it, and O2 excludes them.

If your usage swings from month to month, Sky's approach suits you better on a capped plan. If you're on unlimited data, rollover makes no difference either way.

Which is better for using your phone abroad?

O2 includes EU roaming on its plans, up to 25GB a month, and it's the only big network with no daily fee. Sky charges £2 a day through Roaming Passport Plus, which covers over 120 destinations. It's a wider list than the EU but costs extra every day you use it.

On a week in Spain, that's £14 with Sky and nothing extra with O2, based on the daily fee Sky publishes. For regular trips within Europe, O2 is the simpler choice. Our EU roaming guide covers every network's charges and caps.

Is coverage the same on Sky Mobile and O2?

Yes, because the masts are the same. Ofcom's January 2026 figures for O2's network are the ones that apply to both. They show 4G outdoors at 99.6% of premises, 4G indoors at 95.5%, and 5G outdoors at 86.2%. In rural areas, indoor 4G drops to 82.0%, so a quick postcode check is still worth doing.

You can see how O2 compares with the other three networks near you on our mobile coverage map. Whatever the result, it applies to Sky Mobile too.

What extras does each network add?

O2's main perk is Priority, a free rewards app with weekly offers from brands such as Greggs, cinema deals and 48-hour ticket presales. It's open to every O2 customer, pay as you go included. O2 also runs Multisave: add more lines to one account and each extra eligible line gets 20% off its airtime, up to 20 numbers. The first line isn't discounted.

Sky's extras lean on the rest of the Sky household. Its plans page lets you "change your data plan whenever you like", so you can move up or down as your needs change. Sky customers can also use Sky VIP, the loyalty scheme that covers Sky's TV and broadband too.

If you already pay Sky for TV or broadband, its perks join up with what you have. If you want several lines on one bill, O2's Multisave is the more structured discount.

How do their customer service records compare?

Ofcom's latest complaints figures, for January to March 2026, recorded 3 complaints per 100,000 O2 customers and 4 for Sky Mobile, against an industry average of 2. Ofcom treats O2's figure as comparable with the average. Sky Mobile had the highest figure of the networks reported.

Ofcom's 2024 customer service survey paints a closer picture. Sky scored 87% for overall satisfaction and O2 scored 85%, against an 88% average. Average call waiting times differed more: 1 minute 12 seconds for Sky and 3 minutes 27 seconds for O2. O2 also has shops across the country. Sky offers switching support run by real people, 24 hours a day.

If you prefer to sort problems face to face, O2's stores matter. If you'd rather call and get through quickly, Ofcom's survey figures favour Sky.

Why you might choose Sky Mobile

• You want unlimited or high data at a lower monthly price, and a 12-month term suits you.
• Your usage varies, and you'd use rollover to save spare data for busier months.
• You already have Sky TV or broadband and want everything on one account.
• You'd rather have a way out than a known rise, since any Sky price change comes with a penalty-free exit.

Why you might choose O2

• You travel in Europe and want roaming included without a daily fee.
• You want to know every price rise before you sign, in pounds and pence.
• You'd use Priority, or add several lines through Multisave.
• You want a 30-day plan, or the option to walk into a shop.

How do you switch between Sky Mobile and O2?

Coverage won't change, because both use O2's masts. To keep your number, text PAC to 65075 from your current phone. The code arrives within a minute, and your new network completes the switch within one working day under Ofcom's rules. Our switching guide covers each step.

Leaving either before your term ends costs an exit fee. O2 charges the airtime left, less 4%. Sky works from a published table for each plan. Our mobile exit fee calculator estimates both.

Sources and how we checked

Prices, contract lengths and scheduled rises come from our live deal feed and refresh whenever the site updates. We checked Sky's mobile plans page and O2's price guide and Multisave page on 23 September 2026. Service figures come from Ofcom's telecoms complaints data and Comparing Customer Service report. Coverage figures come from Ofcom's Connected Nations update for January 2026.