Best O2 SIM offers: 40GB for £8, 10GB for £7
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Find out which of O2's plans came out top when we compared their pricing on SIM only with the other UK mobile networks. Last updated: 17th August 2026.
O2's best SIM only deals
The best value SIM only deal on O2 this month
just
£8
a month
✔ Unlimited mins and 40GB data See full deal
at o2.co.uk
(opens in new window)
Out of all the SIM only plans available this August on O2, we'd say their best value deal is their discounted 12‑month SIM below, which gets you 40GB data, plus unlimited minutes and texts for £8 a month:
You can beat it for price if you don't need your SIM to be with a provider using the O2 network. But if that's a must, then it is the lowest-cost SIM with 40GB data or more. See lower-priced networks' deals here:
£7 for 10GB is O2's next best SIM deal in August
just
£7
a month
✔ Unlimited mins and 10GB data See full deal
at o2.co.uk
(opens in new window)
If you need less data, have a look at O2's discounted 10GB SIM below at £7 a month, as it's another good deal. It's on a 12‑month plan and comes with 10GB data, unlimited minutes and texts:
While this is a good enough deal to make it into the best of O2's SIMs, you can beat it for price (even if you definitely want a provider that uses the O2 network). Here are other networks you can beat it on:
There's also a nice 75GB for £10 plan with them this month
just
£10
a month
✔ Unlimited mins and 75GB data See full deal
at o2.co.uk
(opens in new window)
To get even more data, another option for you on O2 is their discounted 12‑month SIM below, which costs £10 a month for 75GB data and comes with unlimited minutes and texts:
It's actually possible to beat this deal if you're not fussed whether your SIM is with a provider using the O2 network. But if you are, it is the current best-priced option. See the networks with cheaper plans here:
Or their £12 for 100GB SIM plan is worth a look too
just
£12
a month
✔ Unlimited mins and 100GB data See full deal
at o2.co.uk
(opens in new window)
For people who need even more data, O2 have got a discounted £12 deal on SIM only we think's worth looking at. It gets you 100GB data, unlimited minutes and texts and it's a 12‑month plan:
It might not be the lowest-cost SIM only deal with 100GB data or more on the entire market but if you're sure you need a SIM using the O2 network, it is the best-priced. 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