Three's best SIMs: 25GB for £7, 60GB for £9
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Compare pricing on Three's SIM only this month vs all the other UK mobile networks. We've identified their best options. Last updated: 7th October 2025.
Three's best SIM only deals
This month's overall best Three SIM only deal
just
£7
a month
✔ Unlimited mins and 25GB data See full deal
at three.co.uk
(opens in new window)
Three's best SIM only plan this October in our opinion is their discounted £16 £7, 12‑month deal below, which comes with 25GB data, plus unlimited minutes and texts for your money:
With £9 off per month, the total saving over the deal’s 12 months adds up to £108.
In comparison to the rest of Three'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 Three network. See lower-priced networks' deals here:
Their £9 SIM with 60GB is our next favourite this October
just
£9
a month
✔ Unlimited mins and 60GB data See full deal
at three.co.uk
(opens in new window)
To satisfy bigger data needs, we'd say this is one of Three's best deals on SIM only this month too. It's a discounted 12‑month plan, comes with 60GB data, unlimited minutes and texts for £16 £9 a month:
You’ll save £84 in total when you add up that £7 monthly saving over the deal’s 12 months.
It does enough to get into our pick of Three's best SIMs but that doesn't mean it's unbeatable on price. Other providers (even ones that use the Three network) can beat it. Here are other networks you can beat it on:
We also like their £12 for 120GB plan
just
£12
a month
✔ Unlimited mins and 120GB data See full deal
at three.co.uk
(opens in new window)
If you think you'll need even more data, have a look at Three's discounted 120GB SIM below at £18 £12 a month, as it's another good deal. It's on a 12‑month plan and comes with 120GB data, unlimited minutes and texts:
It’s a total discount of £72 over the 12 months, when you add up the deal’s monthly £6 saving.
Compared to Three'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 Three network. See the networks with cheaper plans here:
Their unlimited data for £18 SIM is another good option
just
£18
a month
✔ Unlimited mins and unlimited data See full deal
at three.co.uk
(opens in new window)
For those needing even more data, another option for you on Three is their discounted 12‑month SIM below, which costs £28 £18 a month for unlimited data and comes with unlimited minutes and texts:
Add up that monthly saving of £10 over the full 12 months and you’re looking at a total discount of £120.
It might be one of Three'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 Three network. Here's which other networks can beat it:
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How Three compare on SIM only prices and benefits
We said in our full review of the Three network that our favourite thing about them is their fast 4G and 5G speeds as well as their encouraging 5G coverage.
On SIM only you can take a 1-month, 12-month or 24-month contract. Typically the longer the contract, the lower your monthly cost. But it’s always worth shopping around to find their best current deal.
Three’s “Lite” plans are much cheaper than the sorts of deals you’d get on other main networks. Three also have some premium plans with extra benefits baked in. You can take these on 12 or 24-month contracts.
All Three plans give you access to their handy Three+ rewards app. And you get EU and worldwide roaming passes included on their premium Value and Complete plans, as well as these other benefits.
Useful link: Read our full Three review
Other good things to know about Three’s SIM only plans
Three will send your SIM card within 3-5 working days. You’ll receive a package with every size of SIM in it, so you can fit your SIM into every phone. Three also offer eSIMs (see more info here).
You can return your SIM within 14 days to get a full refund if you’re not satisfied. Returning things you bought in a Three store is a bit more tricky, so read the full terms and conditions here to learn more.
To join on any Three SIM only contract you’ll have to pass a credit check. If you were rejected for a contract on Three then you can either take a monthly PAYG bundle or top up with credit and pay as you go.
If you want to keep your number when switching to Three from another network, you can do so by requesting a PAC from your old provider and giving it to Three at any time. Here’s their guide on how to do this.
Useful link: Compare all Three SIMs