The best SIM only offers on O2: January 2025
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We've compared pricing on all of O2's pay monthly SIM only to find which ones stack up best against the rest of the market. Last updated: 15th January 2025.
O2's best SIM only deals
Our favourite SIM only deal of the month on O2
just
£10
a month
✔ Unlimited mins and 40GB data See full deal
at o2.co.uk
(opens in new window)
From all the options O2 have got available this January on SIM only, we think this discounted £22 £10 12‑month deal is their best. For your £10 a month, you get 40GB data alongside unlimited minutes and texts:
Unlimited minutes + Unlimited texts + 20GB 40GB data (5G) = £22 £10 a month (12‑month contract)
See full deal
That means a total saving of £144 when you add up the £12 discount over 12 months.
There are other networks charging less for a SIM with 40GB data or more but this is the best current option with a provider that uses O2. Here are other networks you can beat it on:
Unlimited minutes + Unlimited texts + 50GB data (5G) = £7.95 £3.98 a month for 3 months, then £7.95 (12‑month contract)
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Unlimited minutes + Unlimited texts + 40GB data (5G) = £7 a month (1‑month contract)
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Unlimited minutes + Unlimited texts + 16GB 50GB data (5G) = £8 a month (1‑month plan, no contract)
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Unlimited minutes + Unlimited texts + 40GB data (4G) = £8 a month (12‑month contract)
See full deal
🛈 Increased to: £9.00 on April 1 2025
Unlimited minutes + Unlimited texts + 25GB 40GB data (5G) = £16 £8 a month (12‑month contract)
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Unlimited minutes + Unlimited texts + 120GB data (5G) = £10 a month (12‑month contract)
See full deal
Their £8 SIM with 20GB is our next favourite this January
just
£8
a month
✔ Unlimited mins and 20GB data See full deal
at o2.co.uk
(opens in new window)
For people who don't need that much data, we think this discounted 20GB is one of the best SIM only plans on O2 too. It's on a 12‑month deal, comes with unlimited minutes and texts - all for £22 £8 a month:
Unlimited minutes + Unlimited texts + 20GB data (5G) = £22 £8 a month (12‑month contract)
See full deal
In total, that discount of £14 a month means you’re looking at a saving of £168 over the 12‑month deal.
It can actually be beaten on price if you don't need your SIM to be with a provider that uses the O2. If you do need that, it is the cheapest SIM with 20GB data or more. See the networks with cheaper plans here:
Unlimited minutes + Unlimited texts + 25GB data (5G) = £8 £4 a month for 12 months, then £8 (24‑month contract)
See full deal
Unlimited minutes + Unlimited texts + 20GB data (5G) = £9.90 £6.90 a month (1‑month plan, no contract)
See full deal
Unlimited minutes + Unlimited texts + 50GB data (5G) = £7.95 £3.98 a month for 3 months, then £7.95 (12‑month contract)
See full deal
Unlimited minutes + Unlimited texts + 40GB data (5G) = £7 a month (1‑month contract)
See full deal
Unlimited minutes + Unlimited texts + 20GB data (5G) = £8 £4 a month for 6 months, then £8 (1‑month plan, no contract)
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Unlimited minutes + Unlimited texts + 16GB 50GB data (5G) = £8 a month (1‑month plan, no contract)
See full deal
Unlimited minutes + Unlimited texts + 40GB data (4G) = £8 a month (12‑month contract)
See full deal
🛈 Increased to: £9.00 on April 1 2025
Unlimited minutes + Unlimited texts + 25GB 40GB data (5G) = £16 £8 a month (12‑month contract)
See full deal
We also like their £22 for unlimited data plan
just
£22
a month
✔ Unlimited mins and unlimited data See full deal
at o2.co.uk
(opens in new window)
For even more data, we also think this £22 O2 SIM is one of their best options. It comes with unlimited data, unlimited minutes and texts on a 24‑month deal:
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £22 a month (24‑month contract)
See full deal
If you're open to joining other networks than O2, you can actually get a similar deal for less, even with providers whose SIMs also use the O2 network. Here's which other networks can beat it:
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £16 £8 a month for 6 months, then £16 (24‑month contract)
See full deal
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £18 £0 a month for 3 months, then £18 (24‑month contract)
See full deal
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £20 £16 a month (1‑month plan, no contract)
See full deal
🛈 No annual price rises
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £16 a month (1‑month contract)
See full deal
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £26 a month (12‑month contract)
See full deal
🛈 Annual Price Increase: monthly plan increases annually on 1 April by £1.80
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £20 a month (24‑month contract)
See full deal
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £25 £20 a month (24‑month contract)
See full deal
🛈 No annual price rise for Clubcard holders
Unlimited minutes + Unlimited texts + Unlimited data (5G) = £22 a month (24‑month contract)
See full deal
🛈 Prices rise each year on March 31st by £1.50
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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