Best SIM only on O2: 40GB for £8, 10GB for £7
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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: 16th July 2026.
O2's best SIM only deals
Our best-rated O2 SIM only deal this month
just
£8
a month
✔ Unlimited mins and 40GB data See full deal
at o2.co.uk
(opens in new window)
Looking at what you can get on SIM only with O2 this July, our best-rated deal would be their discounted 12‑month plan below, which comes with 40GB data, plus unlimited minutes and texts for £8 a month:
It's currently the best priced 40GB data or more SIM only deal on a provider using the O2 network, even if you can beat it on price if you're open to ones not on O2. See lower-priced networks' deals here:
Their £7 for 10GB plan is a decent deal for July
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, you might like the discounted £7 SIM only deal running on O2 at the moment. It's a 12‑month plan, which comes with 10GB data, unlimited minutes and texts too:
It's a good enough deal to get into O2's best SIMs but you can actually get a lower price for a similar plan elsewhere, even if you definitely want it to use the O2 network. Here are other networks you can beat it on:
They're also offering 75GB for £10 on SIM only currently
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, 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 75GB data, unlimited minutes and texts for £10 a month:
It might not be the lowest-cost SIM only deal with 75GB 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. See the networks with cheaper plans here:
£12 for 100GB is O2's next best SIM deal in July
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, have a look at O2's discounted 100GB SIM below at £12 a month, as it's another good deal. It's on a 12‑month plan and comes with 100GB data, unlimited minutes and texts:
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 100GB data or more option. 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