50 GBof 5G data
£8.00 a monthuntil April 2027then price rises every April in contract by £2.50Price details
12 month contract
Roam up to 25GB in 48 destinations
Look for
No price rise
in your resultsCompare O2 SIM only deals
If you’re looking for a new SIM deal, O2 has plenty to offer, including 5G speeds, priority tickets at O2 venues and inclusive EU roaming.
Sorted by: Uswitch Promoted
List of SIM Only deals
- eSIM compatible
- 50 GBof 5G data£8.00 a month
1 month contract
eSIM compatibleRoam up to 25GB in 48 destinations
- 80 GBof 5G data£10.00 a monthuntil April 2027then price rises every April in contract by £2.50Price details
12 month contract
eSIM compatibleRoam up to 25GB in 48 destinations
- 120 GBof 5G data£12.00 a monthuntil April 2027then price rises every April in contract by £2.50Price details
12 month contract
eSIM compatibleRoam up to 25GB in 48 destinations
- 80 GBof 5G data£10.00 a month
1 month contract
eSIM compatibleRoam up to 25GB in 48 destinations
- 10 GBof 5G data£7.00 a monthuntil April 2027then price rises every April in contract by £2.50Price details
12 month contract
eSIM compatibleRoam up to 10GB in 48 destinations
- 10 GBof 5G data£7.00 a month
1 month contract
eSIM compatibleRoam up to 10GB in 48 destinations
- 120 GBof 5G data£12.00 a month
1 month contract
eSIM compatibleRoam up to 25GB in 48 destinations
- 250 GBof 5G data£15.00 a month
1 month contract
eSIM compatibleRoam up to 25GB in 48 destinations
- 250 GBof 5G data£15.00 a monthuntil April 2027then price rises every April in contract by £2.50Price details
12 month contract
eSIM compatibleRoam up to 25GB in 48 destinations
Deals last updated on:
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TrustScore 4.7 | 42,273 reviewsHow do I choose the best O2 SIM only deal?
According to Signal Checker, O2 delivers 99% 4G coverage across the UK and 5G in a growing number of locations. It’s also one of the only major networks that still offers EU roaming at no extra charge. It also has a fantastic rewards app with freebies, discounts, and priority tickets for events at O2 venues.
Once you’ve decided on signing up for an O2 SIM, the next thing you need to work out is how much data you need. All O2 SIM deals come with unlimited calls and texts, so the main decision you need to make is how much data you think you’ll need and how much you want to pay per month. Generally, an average smartphone user gets through roughly 8-20GB a month. This is typically enough to cover general use, like checking emails, sending WhatsApp messages and scrolling through social media.
However, data options can go well over 100GB and even to unlimited tariffs. Prices will often go up the higher the cap goes, though. Much of what you decide depends on how much time you spend connected to Wi-Fi at home or work. So, if you’re on the move a lot, you might want to consider signing up for a larger data plan.
If you’d like to know how much data you use in a month, check your network's app. There, you’ll find a monthly breakdown of your usage.
Why choose an O2 SIM only deal?
Excellent coverage: O2 delivers fast 4G coverage to 99% of the UK and has a fast 5G network that spans a growing number of towns and cities around the country. So, you should be able to enjoy fast speeds from almost anywhere in the UK.
Inclusive EU roaming: O2 is one of the few networks in the country that has chosen not to reintroduce roaming charges for travel to EU countries after Brexit. This means that if you’re on O2, you can continue using your regular allowance of calls, texts, and data at no extra cost while in any EU country.
Volt benefits: If you have an eligible O2 phone plan and Virgin Media broadband, Volt doubles your O2 data allowance and boosts your broadband speed to the next available tier
Named Best Network for Roaming in 2025: O2's roaming is so helpful for customers travelling abroad that it won our Uswitch Award for the Best Network for Roaming in 2025. It also won Best Mobile Network Coverage in 2026.
O2 Priority: O2 is famous for its O2 Priority app, which allows users to buy tickets for events at O2 venues before they go on general sale. The app also offers regular competitions, special offers, and freebies for its customers to enjoy.
Free public Wi-Fi – Login to thousands of free Wi-Fi hotspots across the UK – you don’t even need to be an O2 customer.
What SIM only deals does O2 offer?
O2 offers a wide range of SIM only deals, from cheap SIM plans to big, unlimited data contracts. At the time of writing, O2 SIM only plans often start from just £7 a month for 10GB of data, up to a 250GB data SIM for £15 a month. There are unlimited data options too, but you’ll need to sign up for a minimum contract length for the cheapest deal.
At the time of writing, O2 currently offers SIMs to suit all needs, including:
O2 delivers 5G SIM only deals as standard now, with even its cheapest plans able to connect to 5G networks. However, you should bear in mind that your mobile phone also needs to be 5G-enabled to take advantage of those faster speeds.
O2’s SIM only contracts are available on 12- and 24-month plans, as well as rolling 30-day options. You can also opt for an O2 pay-as-you-go SIM, which means that you only pay for the usage you need. This might be a good option if you’re not planning to use your phone regularly.
But if you plan to use it for regular calls, texts, and internet access, you’d probably be better off signing up for a cheap O2 SIM deal.
Want an O2 phone contract instead?
Take a look at our best pay monthly deals from O2 today.
Can I use my O2 SIM abroad?
Yes, you can use your O2 SIM abroad, although depending on your destination, it might cost you more. O2 won our Uswitch award for Best Network for International Roaming in 2025 because it was the only major UK network that didn’t reintroduce international roaming charges in EU countries after Brexit.
This means you can use your monthly allowance for minutes, messages, and data (capped at 25GB) without paying extra charges in any EU country. If you’re travelling further afield, such as to the US, Canada or Australia, you can buy a bolt-on for an extra £7 a day.
How do I activate my SIM?
O2 makes it really easy to activate its SIM cards. If you’ve received a physical SIM card after signing up, it should be ready to go. All you need to do is pop it into your handset, and it should start working straight away. If it doesn’t, you may need to restart your device.
If you’ve got an eSIM, you’ll need to download the eSIM profile onto your device. To do this, scan the QR code included in your eSIM pack.
Can I keep my number with an O2 SIM only deal?
Yes, keeping your number is easy if you’re switching to an O2 SIM only deal. Text PAC to 65075 to receive your PAC code. Then, contact O2 and give them the code so they can transfer your new number for you.
You can call O2 on 0344 809 0202.
What happens at the end of an O2 SIM only contract?
Once your contract is nearing its end, you’ll receive an email or text message from O2. Once you’ve received this, you can access your O2 app and find upgrade options.
However, these aren’t generally the most competitive deals, and you should be able to find options that are much better value for money if you shop around. If you want to check out some options, compare our best SIM only deals on Uswitch.
Other networks
Is O2 not right for you? There are many UK networks with a range of products available. No matter your budget, data requirements, or handset preference, you’ll be able to find the ideal package:
Written by Nick Baker, Senior Editor
FAQs
Is it cheaper to get a SIM only or a phone contract?
It’s almost always much cheaper to get a SIM only deal instead of a mobile phone contract. This is because you’re only paying for your calls, texts and data, rather than paying off the cost of a handset. However, if you don’t have a mobile phone you’re happy with, getting a phone contract can help you spread the cost of a new device. Check out our best O2 mobile phone deals.
Are O2 SIM cards free?
O2 doesn’t charge for SIM cards, so you can send off for a pay as you go one or sign up for a contract without having to pay for the card. However, you will need to pay to use the SIM, whether that’s by signing up for a monthly contract, or choosing O2 pay as you go.
Do I have to top up my O2 SIM every month?
If you choose an O2 pay as you go SIM, you don’t need to top up every month. However, if you don’t top up or purchase a bolt-on at least once every six months, your mobile will be disconnected and you’ll end up losing any credit you had left. On O2, the minimum top-up requirement is £10.
Can I get a 5G enabled O2 SIM card?
Yes, all new O2 SIMs are now 5G enabled. However, you’ll need to use it in a 5G-compatible mobile phone and be in an area where 5G is up and running if you want to take advantage of these superfast speeds.