Best SIM offers on iD Mobile: 20GB for £6, 40GB for £7
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We check iD's SIM only pricing against other mobile networks to identify the best offers they've got running this month. Last updated: 13th March 2026.
iD Mobile's best SIM only deals
This month's overall best iD Mobile SIM only deal
just
£6
a month
✔ Unlimited mins and 20GB data See full deal
at idmobile.co.uk
(opens in new window)
We'd say the best SIM only plan iD Mobile are selling this March is their discounted 1‑month 20GB deal below, which comes in at £6 a month and includes unlimited minutes and texts too:
It's not actually the cheapest SIM only deal on the market at the moment with 20GB data or more but it is the lowest-priced plan on any provider using the Three network. Here are other networks you can beat it on:
iD's £7 for 40GB is our next best choice now
just
£7
a month
✔ Unlimited mins and 40GB data See full deal
at idmobile.co.uk
(opens in new window)
If you want more data, iD Mobile are also offering this discounted £7 SIM, which includes 40GB data, unlimited minutes and texts on a 1‑month plan. It's another of their best deals:
Compare this with similar deals from other networks with 40GB data or more and you'll find iD's actually comes out best on price. Have a look at the nearest other providers get for comparable SIM only deals:
Their £8 SIM with 60GB is our next favourite this March
just
£8
a month
✔ Unlimited mins and 60GB data See full deal
at idmobile.co.uk
(opens in new window)
For even more data, you might like the discounted £8 SIM only deal running on iD Mobile at the moment. It's a 1‑month plan, which comes with 60GB data, unlimited minutes and texts too:
It's certainly a good deal from iD. No other network can beat them for price on a SIM only plan with 60GB data or more. See under the dropdown to see how the competition it undercuts:
We also like their £9 for 108GB plan
just
£9
a month
✔ Unlimited mins and 108GB data See full deal
at idmobile.co.uk
(opens in new window)
If you're even more data-hungry, we'd say this is one of iD's best deals on SIM only this month too. It's a discounted 1‑month plan, comes with 108GB data, unlimited minutes and texts for £10 £9 a month:
With £1 off per month, the total saving if you spent a year on the deal adds up to £12.
There's not currently a better SIM only deal on the market than iD's one above if you want 108GB data or more. Here's the closest their competitors get for similar plans:
Their unlimited data for £15 SIM is another good option
just
£15
a month
✔ Unlimited mins and unlimited data See full deal
at idmobile.co.uk
(opens in new window)
To satisfy even bigger data needs, have a look at iD Mobile's discounted unlimited data SIM below at £18 £15 a month, as it's another good deal. It's on a 1‑month plan and comes with unlimited data, unlimited minutes and texts:
You’ll save £36 if you stayed on the deal a whole year, adding up that £3 monthly saving.
iD's is actually the best-priced SIM only deal in the UK at the moment for unlimited data. No other providers can beat it for monthly cost. Here's each network's nearest plan:
Compare all SIM only plans
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How iD Mobile's deals compare with other networks
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How iD’s benefits and SIM only prices stack up
In our review of iD Mobile, we said we liked that they offered full access to Three’s network (including identical 5G speeds and coverage) on low-cost deals. And they have an excellent WiFi calling scheme as well.
You can choose either a 1-month, 12-month or 24-month contract on iD. It tends to be the case that longer contracts cost you less per month. But it’s still worth checking to see what their best current deals are.
iD tend to offer great value on all their SIM only plans, and the cost of your plan won’t increase during your contract so you can hold onto that value. They’re usually one of the cheapest ways onto Three’s network.
They’re fairly low-frills, but they do have a good data rollover scheme that lets you keep unused data for your next month. They also offer inclusive EU roaming. But they don’t offer much else.
Useful link: Read our full iD Mobile review
What else you should know about iD’s SIM only plans
Your iD Mobile SIM card will be delivered within 2-3 working days after ordering. You’ll get each size of SIM card in your package to fit any phone. iD don’t offer eSIMs yet (see the providers that do here).
When you order anything online you have 14 days to get a full refund, and this is also the case for SIM cards. Here’s how you can get a refund if you’re unhappy with your SIM.
You’ll have to pass a credit check to join iD, no matter if you want to join on a 1-month, 12-month or 24-month contract. If you’ve been rejected for a contract you can still join on a PAYG monthly bundle.
If you’re switching from one network to get onto iD Mobile then you can keep your number by requesting a PAC from your current provider to give to iD. Here’s more info on how to do that.
Useful link: Compare all iD SIMs