Networks on O2: virtual operators using their signal ranked

Virgin Mobile have moved to O2’s network after having used Vodafone’s for a while. This means you get the same 5G/4G/3G/2G as being on O2 directly. You can see how the two compare in our Virgin vs O2 guide here.

On top of that, Virgin Mobile users also get access to a huge network of over 4.3 million WiFi hotspots up and down the country. That includes some at Underground ticket barriers and stations.

Virgin include EU roaming, but they have a complicated fair usage limit on data usage abroad (use their calculator here). And their WiFi calling is a step behind O2’s, as fewer Android models are supported.

But for SIM only, Virgin typically trounce O2 on price and in terms of flexibility, as all of their plans are on 1-month deals. This is on top of their social media data and data rollover benefits that come on every plan.

Virgin Mobile SIM only deals

Their phone contracts also beat O2 on price, but that’s a trade-off for less flexibility. But you can still choose between a 24-month and 36-month contract and change your usage plan month to month.

Useful link: Read our full Virgin Mobile network review

With Sky you get 5G-access on every plan and WiFi calling and 4G calling as standard (read our Sky vs O2 guide for more details). Like with Virgin, they give you an identical network experience to being on O2.

From testing Sky Mobile for our review, we weren’t able to find any coverage differences. And despite some Sky customer forum discussion, we’ve never been able to find any speed differences between the two either.

That’s great considering that Sky’s phone deals are typically better value than O2’s, while their small to mid-range SIM only contracts are also lower cost than O2’s (for larger plans it’s worth comparing them):

Sky Mobile SIM only deals

You also get Sky’s “Piggybank” benefit that lets you hold onto your unused data or trade it for discounts. And their Sky Watch benefit lets you stream Sky’s TV apps on data eating into your allowance.

The main downside of Sky is that they don’t offer inclusive EU roaming, while O2 do. If you’re not planning on going abroad, Sky are a great choice. Otherwise, you might want to look at Virgin or the other providers below.

Useful link: Read our full Sky Mobile network review

Tesco Mobile are another good alternative to O2. They were part-owned by O2 back in the day and still use their network. Coverage is identical to O2 and you get 5G access on every plan (read our review here).

The main thing lacking on Tesco Mobile vs O2 is WiFi calling and 4G calling. These kick in when conventional mobile signal is weak (like indoors) and let your phone use WiFi to make/take calls instead.

You’re essentially trading WiFi/4G calling for better prices. Tesco Mobile typically beat O2 on value for phone contracts. And Tesco tend to offer better value SIM only deals, especially on mid and low range plans:

Tesco Mobile SIM only deals

Clubcard holders get exclusive discounts and can use their Clubcard points to get money off their mobile bill. And Tesco offer Family Perks if you’ve got multiple plans. But Tesco no longer include EU roaming.

They’ve also got a great customer service record and there’s the convenience of being able to drop in and see their staff whenever you’re doing your shopping at Tesco too. A decent choice all round we think.

Useful link: Our full network review of Tesco Mobile

giffgaff now include 5G-access on every plan, meaning you get the same coverage as being on O2 directly. And they even let you access O2’s network of WiFi hotspots. However they’re still missing WiFi/4G calling.

Some giffgaff users have complained of slower speeds on giffgaff vs O2. But we weren’t able to replicate that in our tests. In our giffgaff review we said you’ll expect get the same speeds on giffgaff and O2.

We like the flexibility you get with giffgaff’s SIM only plans. There’s no contract, you’re free to leave whenever and change plans. Although price-wise, they’re beatable, though cheaper than O2 for 1-month plans:

giffgaff's latest SIM only deals

It pays to compare giffgaff’s phone contracts too. Although these are very flexible and based on finance for the phone, the prices aren’t a slam dunk in terms of beating O2 directly or via retailers selling phones on O2.

And unlike some of the providers on this list, giffgaff still offer EU roaming (limited to 5GB abroad). But their customer service is online-only. Worth bearing in mind if you’re not very tech-savvy.

Useful link: Read our full giffgaff review

Lycamobile are a low-cost provider on O2 that specialise in international calls. Even if you’ll never call abroad, they’re still a good choice as they get you identical 5G/4G/3G/2G signal as O2.

Lycamobile are generally very low-frills. But you do get a nice flexible plan you can change each month, not renew or leave altogether. And if you have family or friends abroad, they’ve got good international rates.

Lycamobile's latest SIM only deals

Lycamobile don’t offer WiFi calling or 4G calling. While O2’s call signal is typically good at getting indoors, but you can still struggle if you’re far from the mast. In that case you’re out of luck.

And Lycamobile let you call them if you need help, or you can use their online chat agent if you prefer. If you don’t mind missing out on WiFi/4G calling, then Lycamobile are a great value choice.

Useful link: Learn more about Lycamobile