O2 SIM Only Deals 2024 | Compare Contacts & Plans

Your guide to O2 SIM only deals

O2 is one of the UK's four network providers – the others being Three, EE and Vodafone. All other providers piggyback off one of these four networks. Network providers tend to offer a lot more than regular providers, often selling tablets, laptops, all kinds of smart devices, handsets (of course), and SIMs. Here we'll be looking exclusively at O2's SIM only deals and what makes them worth considering.

In this guide...

Key features Roaming

Is it any good? FAQs

Data & calling

Key features

Flexible contract lengths – O2 let's you choose choose from 30-day, 12-month, or 24-month SIM only contracts to suit your needs, and broadly speaking the longer the contract, the less you will pay per month
Unlimited calls and texts – All O2 SIM only plans come with unlimited minutes and texts, though some additional rules do apply. O2 offers unlimited data SIMs too, but most of its range of SIMs come with a limit – the more you pay, the more data you get
5G connectivity – 5G connectivity is provided at no extra cost so long as you have a 5G-compatible device and are an area that has 5G coverage from O2
Roam in up to 102 countries – Those on a Volt or Plus Plan can roam in 27 European destinations for free, while those on an Ultimate Plan can roam for free in a further 75 countries. If you're not on an Ultimate plan, you can bolt on those extra countries for £6 per day
O2 Priority – Gain access to exclusive offers, early ticket sales, and unique experiences through the O2 Priority app, enhancing your everyday experiences
O2 Extras – Depending on your plan there may be additional perks such as up to six months of Disney+, Amazon Prime, or other services, adding extra value to your subscription
Data rollover on Rolling Plans – O2 has unique 'Rolling Plans' that allow you to carry over all your unused data to the next month without penalty. Regular SIM plans not named 'Rolling' do not have this feature though, so be aware
O2 Wi-Fi hotspots – You can connect to thousands of O2 Wi-Fi hotspots across the UK for free, which will help you conserve your data allowance when out and about, provided you're somewhere it's available

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Data and calling

O2 is one of the UK's four mobile networks (soon to be three when Three and Vodafone complete their merger next year). As such, it operates all its own infrastructure (masts and such), and is that little bit easier to determine the sort of signal you're likely to get as a result – O2's coverage checker is one of the better ones.

Here are the main features of an O2 SIM when it comes to data and calling.

5G data speed – O2’s 5G network offers average speeds around 90-100Mbps, depending on your location and network conditions
4G data speed – O2’s 4G network delivers average download speeds of 17-20Mbps, which is reliable for streaming and browsing but not the fastest available
Mobile tethering – With O2, you can tether without limits on all its SIM only plans. Handy for getting your laptop or tablet online if your home broadband drops out
Wi-Fi calling – If your mobile signal is patchy, O2’s Wi-Fi calling comes as standard on all its SIMs. As long as you’ve got Wi-Fi, you can make and receive calls just like normal. It’s available on most phones, but you will need to check yours is compatible
Spend caps – Don’t want to risk an unexpected bill? O2 lets you set a monthly spend cap to keep costs under control, whether it’s to prevent premium-rate calls, limit out-of-plan charges, or to block accidentally buying something you didn’t mean to
International calling – Whether you’re calling friends abroad or keeping in touch with family, O2 offers decent international rates. You can also add bolt-ons for cheaper calls to specific countries if you’re phoning abroad often. You'll need to look up individual rates to specific countries on the O2 website

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Roaming on O2

O2 is one of the better networks when it comes to roaming, offering free roaming in 27 EU countries, and the ability to either bolt on another 75 for £6 per day, or have those extra countries included in the upper-echelon Ultimate SIM plans. It's nothing if not convenient. However, we do advise checking the price of a local SIM for some countries and they can sometimes be cheaper, if a little less convenient to get a hold of.

The 'O2 Europe Zone' as O2 phrases it includes 27 countries in which you'll get unlimited texts and calls back to the UK, and 25GB of your data allowance to use as you please. Note that calling to numbers within the country you're visiting will still be charged at the international rate that would apply if you were calling it from the UK. The 27 'Europe Zone' countries are:

Austria, Azores, Belgium, Bulgaria, Canary Islands, Croatia, Cyprus (not including Northern Cyprus), Czech Republic, Denmark, Estonia, Finland, France, French Guiana, Germany Gibraltar, Greece, Guadeloupe, Guernsey, Hungary, Iceland, Ireland, Isle of Man, Italy, Jersey, Latvia, Liechtenstein, Lithuania, Luxembourg, Madeira, Malta, Martinique, Mayotte, Monaco, Netherlands, Norway, Poland, Portugal, Reunion, Romania, Saint Barthelemy, Saint Martin, San Marino, Slovakia, Slovenia, Spain, Sweden, Switzerland, and Vatican City.

We won't list the 75 additional countries you can bolt on with the awkwardly named 'O2 Travel Inclusive Zone Ultimate' add-on. Suffice to say though you'll find the usual suspects in that list, including USA, Australia and so on.

Calling abroad from the UK on O2

Calling or texting any non-UK number will invoke O2's international calling rates, which vary wildly depending on the country you're calling. Just make sure you check what the rate is for wherever it is you're calling or texting so you don't find yourself with an unexpected, hefty bill. Setting a spending cap on your O2 account can also put a useful safeguard against this happening.

If you find yourself calling abroad a lot, you can add the 'International Bolt On' for an additional £3 per month. This reduces the cost of calling and texting abroad to 1p per minute and 6p per text. The bolt on includes and absolutely vast array of countries and you'll be hard pressed to find anywhere in the world where these reduced rates don't apply, making it one of the most cost-effective way to call a whole host of countries throughout the world.

What our expert says...

"O2 is a great pick, especially if you're considering calling abroad a lot, as its International Bolt on is one of the best international calling deals in the business. O2's wider offering beyond SIM only also makes it ery attractive if you ever want to upgrade or add more devices and services to your contract. It's certainly not as cheap as some other providers though, so do consider what it is you need before signing up as there are often cheaper deals out there."

Dan Howdle, Broadband and mobile expert

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Frequently asked questions

Why is O2 quite expensive compared to other providers?

O2 is one of the UK's four network providers, meaning it owns and maintains a vast amount of equipment and infrastructure – this makes it somewhat pricier than providers that piggyback off someone else's network as it simply has higher overheads.

What perks and extras come with an O2 SIM?

O2's Priority programme offers discounts on various non-related products and services, including concert tickets, while its inclusive roaming is quite generous, allowing you to use up to 25GB in any of 27 European countries.

Does O2 offer SIMs with no credit check?

O2's PAYG SIMs do not require a credit check. However, any other O2 SIM will run a credit check when you sign up.

Are O2 and giffgaff the same company?

Yes. All UK mobile providers operate on one of four networks, and giffgaff operates on the O2 network, and is owned by Telefónica UK Ltd, which operates O2. However the service offerings from the two providers are quite different.

Can I switch to O2 and keep my number?

Yes. Porting your existing number to a new provider has never been easier, requiring only the sending of a PAC request text.

Does O2 offer unlimited data SIMs?

Yes. However, it's debatable still whether most people actually need unlimited data since most of us spend most of our time within range of Wi-Fi. O2's unlimited SIMs aren't the cheapest either.

What's the cheapest O2 SIM?

Th cheapest SIM only deal you can get from O2 at the time of writing is £10 per month with unlimited texts and calls and a 30GB data limit. PAYG SIMs from O2 are an even cheaper way of getting onto the network, however calling and data tend to be slightly more expensive to purchase versus an O2 contract.