The quick answer
Chattr's Freedom One plan is the cheapest unlimited data SIM we list, at £15 a month, falling to £14 from month 6 and £13 from month 12. It's a rolling plan with no contract and no credit check.
Unlimited SIM deals compared
| Network | Price | Contract | Good to know |
|---|---|---|---|
| Chattr | £15/mo (drops to £13) | Rolling monthly | Price falls the longer you stay |
| Rewild Mobile | £20/mo | 24 months | 25% of net profits go to nature; £22 on rolling |
| Asda Mobile | £22/mo | Rolling monthly | Acceptable use policy applies |
| 1pMobile | £25/mo | 30-day rolling | Extra SIMs £12.50 each; or £275 a year |
Is "unlimited" really unlimited?
Mostly, yes, for normal use. Most unlimited plans have a fair use or acceptable use policy that lets the network slow speeds for extremely heavy users or stop the SIM being used in things like home broadband routers. For example, 1pMobile says it may slow speeds at busy locations after 500GB in a period. That's far more than most people use.
Do you actually need unlimited?
Most people use under 20GB a month. If you're often on Wi-Fi, a 50GB plan from £10 (1pMobile) could save you money. Try the data calculator on our SIM-only deals page to see what you really need.
Best unlimited deal for families
1pMobile lets you add extra SIMs to its £25 unlimited bundle for £12.50 each, so four unlimited SIMs cost £62.50 a month, about £15.63 per person.
