Cheapest unlimited data SIM-only deals today
Quick answer
The cheapest unlimited data SIM-only plan today is iD Mobile at £14.00 a month on a 1-month rolling plan. Prices checked 30 October 2026.
These are the cheapest unlimited data SIM-only plans we list today, ranked by monthly price. We show the cheapest plan from each network. Check the contract length: one-month plans let you leave at any time, but can cost more.
| # | Network and data | Monthly | Contract | Minimum-term cost |
|---|---|---|---|---|
| 1 | iD Mobile Unlimited data (5G) Unlimited minutes · Unlimited texts · Sold by Mobiles.co.uk | £14.00 | 1-month plan | £14.00 |
| 2 | Sky Mobile Unlimited data (5G) Unlimited minutes · Unlimited texts · Sold by Sky | £20.00 | 24-month contract | £480.00 |
| 3 | Honest Mobile Unlimited data (5G) Unlimited minutes · Unlimited texts · Sold by Honest Mobile | £22.50 | 12-month contract | £270.00 |
| 4 | O2 Unlimited data (5G) Unlimited minutes · Unlimited texts · Sold by O2 | £23.00 | 24-month contract | £612.00 |
| 5 | giffgaff Unlimited data (5G) Unlimited minutes · Unlimited texts · Sold by giffgaff | £25.00 | 18-month contract | £450.00 |
| 6 | Vodafone Unlimited data (5G) Unlimited minutes · Unlimited texts · Sold by Mobiles.co.uk | £26.00 | 24-month contract | £684.00 |
Prices include VAT and can change. Check the price on the retailer’s site before you buy.
Frequently asked questions
What is the cheapest unlimited data SIM-only deal today?
The cheapest unlimited data SIM-only plan today is iD Mobile at £14.00 a month on a 1-month rolling plan. Prices checked 30 October 2026.
Is unlimited data really unlimited?
On most UK networks, yes, for normal use in the UK. Some limit tethering or speeds on cheaper plans, so check the plan’s terms before you buy.
Which network has the best coverage?
It depends on where you live and work. Check your postcode with our mobile coverage checker.
How do you rank these deals?
On price alone, using the live deals we compare from UK networks and retailers. Monthly prices are what you pay after any introductory offer ends. We may earn commission if you buy, but it never changes the order. See how we make money.