Best SIMs on O2: 75GB for £10, 40GB for £8
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See how we rate each of the choices on O2's SIM only, compared with other UK mobile networks' closest plans. Last updated: 7th April 2026.
O2's best SIM only deals
The best overall SIM only deal this month on O2
just
£10
a month
✔ Unlimited mins and 75GB data See full deal
at o2.co.uk
(opens in new window)
Out of all the SIM only plans available this April on O2, we'd say their best value deal is their discounted 12‑month SIM below, which gets you 75GB data, plus unlimited minutes and texts for £10 a month:
In comparison to the rest of O2's current SIM only plans, it's one of the best. But it is beatable on price, even if you're set on joining a provider that uses the O2 network. Here's where you can beat it on other networks:
Their 40GB for £8 SIM is another good option
just
£8
a month
✔ Unlimited mins and 40GB data See full deal
at o2.co.uk
(opens in new window)
For a smaller amount of data, O2 are also offering this discounted £8 SIM, which includes 40GB data, unlimited minutes and texts on a 12‑month plan. It's another of their best deals:
If you don't need your SIM to be on a provider that uses the O2 network, you can beat this deal elsewhere. But if you do, it's the cheapest 40GB data or more option. See lower-priced networks' deals here:
O2's 150GB for £14 plan is a good option too
just
£14
a month
✔ Unlimited mins and 150GB data See full deal
at o2.co.uk
(opens in new window)
For people who need even more data, you might like the discounted £14 SIM only deal running on O2 at the moment. It's a 12‑month plan, which comes with 150GB data, unlimited minutes and texts too:
Compared to O2's other deals, this comes out among the best. But it's worth knowing you can get a lower price elsewhere, even on other providers that use the O2 network. Here are other networks you can beat it on:
Their £12 for 100GB plan is a decent deal for April
just
£12
a month
✔ Unlimited mins and 100GB data See full deal
at o2.co.uk
(opens in new window)
For people who don't need that much data, we'd say this is one of O2's best deals on SIM only this month too. It's a discounted 12‑month plan, comes with 100GB data, unlimited minutes and texts for £12 a month:
It might be one of O2's best deals on SIM only but you can get a lower price for a similar plan on other providers, even ones that use the O2 network. See the networks with cheaper plans here:
They're also offering 250GB for £15 on SIM only currently
just
£15
a month
✔ Unlimited mins and 250GB data See full deal
at o2.co.uk
(opens in new window)
For even more data, have a look at O2's discounted 250GB SIM below at £15 a month, as it's another good deal. It's on a 12‑month plan and comes with 250GB data, unlimited minutes and texts:
This is good for O2 but it's not an unbeatable price. You can get similar SIM only plans for less with some other providers, even ones that also use the O2 network. Here's which other networks can beat it:
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O2’s SIM only prices and benefits compared
In our full review of the O2 network we said we liked their brilliant call signal (3G/2G) coverage, their good 5G coverage and their great WiFi hotspot scheme. We also like their WiFi calling and 4G calling.
You have the choice of 1-month, 12-month and 24-month contracts. Their 24-month contracts are usually much cheaper per month, but it’s best to check their current deals for the best possible offer.
O2’s deals tend to be some of the most expensive of all networks, but they’re a bit more competitive on big data deals. There are some smaller providers on O2’s network who offer better value SIM only deals.
They’re also the only main UK network to still offer inclusive EU roaming on all plans. And you can get extras on premium plans, such as subscriptions to entertainment services and worldwide roaming data passes.
Useful link: Read our full O2 review
Other things to know about O2’s SIM only deals
You’ll get your O2 SIM card between 1-4 working days after ordering (depends on your location). And there are premium delivery options too. You’ll receive each size of SIM for any phone. Or you can take an eSIM.
When your SIM arrives, you have 14 days to return it and get a full refund if you’re not satisfied. This will also cancel your contract. Here’s how you do that.
To prevent customers racking up huge bills they can’t pay, O2 make you pass a credit check to join them. If you have a poor or no credit history you can still join O2 on a PAYG monthly bundle instead.
And if you’re switching to O2 from another network you can keep your number by requesting a PAC from your old provider and giving it to O2 at any point. Here’s how you do that.
Useful link: Compare all O2 SIMs