Unlimited data.
Actually unlimited.
Compare unlimited data SIM deals from the UK's leading networks. No bloated phone contracts, just the data you need at a price that makes sense.
The cheapest unlimited data SIMs we compare are Chattr's Freedom One and iD Mobile, both at £15 per month on 30-day rolling plans. Chattr runs on O2 with no price hikes and no credit check; iD Mobile runs on Three with EU roaming included. Asda Mobile's £22 plan locks its price for 12 months on Vodafone coverage, and O2's Unlimited Classic is £23 direct on a promo price. Nobody needs a 24-month contract for unlimited data any more.
Best unlimited data SIM deals right now
Chattr Freedom One (Unlimited)
iD Mobile Unlimited (1 month)
1p Mobile Unlimited
Asda Mobile Unlimited
O2 Unlimited Classic
VOXI Unlimited
How the plans compare
| Network | Price/month | Contract | Standout | Underlying network |
|---|---|---|---|---|
| Chattr Freedom One | £15.00/month | 30-day rolling | No price hikes, no credit check | O2 |
| iD Mobile Unlimited | £15.00/month | 1-month rolling | EU roaming included | Three |
| 1p Mobile Unlimited | £20.00/30 days | 30-day rolling | Half price first 3 months | EE |
| Asda Mobile Unlimited | £22.00/month | 12 months | Price locked for the term | Vodafone |
| O2 Unlimited Classic | £23.00/month | Promo price to 2 Sep | O2 Priority perks | O2 (direct) |
| VOXI Unlimited | £30.00/month (was £35) | 30-day rolling | No speed restrictions | Vodafone |
Prices verified August 2026 and may change. Click through to see current offers and confirm availability.
What you need to know before you choose
Unlimited data SIM deals have got genuinely good value over the past couple of years. You no longer have to pay a premium for the peace of mind of not watching your data counter. The question now is less about whether to go unlimited and more about which network and which contract length makes sense for you.
Is unlimited data actually unlimited?
For almost all practical purposes, yes. Most UK networks do not impose a hard data cap on unlimited plans. What some networks do have is a fair use policy that can throttle your speed after extremely heavy usage in a short period. For normal streaming, browsing, and working, you will never hit it.
One thing worth checking: some cheaper unlimited plans cap your maximum download speed even if the data itself is unlimited. If you want genuinely fast 5G speeds rather than just unlimited slower data, look at the speed tier on the plan before you buy. 1p Mobile and VOXI both advertise no speed restrictions on their unlimited plans.
Do I still need a long contract for unlimited data?
No. Four of the six plans we compare are 30-day rolling, so you can cancel or switch any time with no penalty. Chattr's Freedom One and iD Mobile's rolling plan, both at £15, are currently the cheapest ways to get unlimited data full stop, and Chattr also commits to no mid-contract price hikes, which the big networks can't say. The exception worth considering is Asda Mobile, which locks its £22 price for 12 months.
Watch for intro pricing too. 1p Mobile runs its unlimited plan at half price for the first three months, and VOXI's unlimited plan is currently £30 instead of £35. Both revert to the standard rate afterwards, so judge the deal on the ongoing price, not the promo.
Does it matter which network the SIM runs on?
More than people realise. Most providers on this page don't own their own network infrastructure. They rent capacity from the big four operators and pass the savings on to you. Between them they cover all four: Chattr runs on O2, iD Mobile on Three, Asda Mobile and VOXI on Vodafone, and 1p Mobile on EE, while O2's Unlimited Classic puts you on the host network directly. Check coverage at your home address and regular locations before you commit. See our full SIM only comparison for more options.
Questions people ask
The cheapest unlimited SIMs we currently compare are Chattr's Freedom One and iD Mobile, both at £15 per month on rolling plans. Chattr runs on O2 with no price hikes and no credit check; iD Mobile runs on Three with EU roaming included. On Vodafone coverage, Asda Mobile's 12-month price-locked plan at £22 is the best value.
For normal use, yes. Most UK networks do not apply a hard cap. Some have fair use policies that may reduce speeds after very heavy usage in a single session, but this rarely affects typical users. Always worth checking the specific terms of the plan before you buy.
The providers we compare cover all four UK host networks: Chattr runs on O2, iD Mobile on Three, Talkmobile, Asda Mobile and VOXI on Vodafone, and 1p Mobile on EE. The best choice depends on which host network has the stronger signal at your specific location, so check coverage at your address first.
Yes. Chattr and iD Mobile at £15, 1p Mobile at £20, and VOXI at £30 are all 30-day rolling with no long-term commitment, so you pay month to month and can cancel any time. Asda Mobile's £22 plan trades that flexibility for a 12-month price lock.
Most do now, but check the specific plan. Some entry-level unlimited deals cap you at 4G speeds even with unlimited data. If 5G matters to you, confirm the plan explicitly includes 5G access and that your handset supports it.
Related deals and guides
Not sure which unlimited SIM is right for you?
Our team can help you find the best deal for your network, budget, and how long you want to commit.
Get help choosingWe may earn a commission when you switch or sign up through links on this page. It’s paid by the provider and never affects the price you pay. Read more about how we earn revenue.