SIM only · unlimited
Unlimited data SIM only deals
The cheapest unlimited data SIM on every UK network, ranked by what you pay over 24 months once April rises are added.
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Is unlimited really unlimited?
For your own phone, yes — but most networks cap tethering and roaming, and some slow speeds on cheaper unlimited plans.
Is unlimited worth it?
If you stream on mobile data or use a hotspot, often yes: unlimited can cost only a few pounds more than 100GB.
Which networks have no April rise?
SMARTY, giffgaff, Lebara, VOXI and iD Mobile’s SIM only plans don’t rise every year.
No price rise- Runs on Three
- 30-day rolling plan
- Credit check applies
- Roaming in 50 countries, 30 GB
£14 a month
Get this dealiD Mobile review →Live price, checked several times a day.
Unlimited data SIM only: every network ranked
| # | Network | Data | Contract | Monthly | Annual rise | 24 months, rises included | |
|---|---|---|---|---|---|---|---|
| 1 | iD Mobile | Unlimited | 30 days | £14 | None on SIM only; phone plans +£1.80 | £336 | Get deal |
| 2 |  Three | Unlimited | 12 months | £12.42 | +£1.80 to £2.30 every April by data | £343.68 | Get deal |
| 3 |  Talkmobile | Unlimited | 30 days | £16 | Check at sign-up | £384 | Get deal |
| 4 |  SMARTY | Unlimited | 30 days | £17 | No annual rise | £408 | Get deal |
| 5 |  Lycamobile | Unlimited | 24 months | £18 | No annual rise announced | £432 | Get deal |
| 6 |  Tesco Mobile | Unlimited | 24 months | £17 | Fixed rise of about 6% every April | £432.48 | Get deal |
| 7 |  Asda Mobile | Unlimited | 24 months | £19 | Check at sign-up | £456 | Get deal |
| 8 |  Sky Mobile | Unlimited | 24 months | £20 | +£1.50 from Feb 2026, not fixed in contract | £480 | Get deal |
| 9 |  Lebara | Unlimited | 12 months | £22.50 | No annual rise | £540 | Get deal |
| 10 |  giffgaff | Unlimited | 18 months | £25 | No annual rise | £600 | Get deal |
| 11 |  O2 | Unlimited | 24 months | £23 | +£2.50 every April | £612 | Get deal |
| 12 |  Vodafone | Unlimited | 24 months | £26 | +£2.50 every April (Basics +£1.50) | £684 | Get deal |
| 13 |  VOXI | Unlimited | 30 days | £35 | No annual rise | £840 | Get deal |
Cheapest plan per network matching this page, checked 27 October 2026. “24 months” adds each network’s April rise for a plan starting this month; on 30-day plans you can leave before a rise.
What to check on an unlimited plan
- Speed caps — some cheaper unlimited plans limit download speeds; fine for streaming on a phone, slower for hotspot use.
- Tethering limits — sharing data with a laptop is often capped by a fair use policy.
- Roaming — unlimited at home doesn’t mean unlimited abroad; EU allowances are usually 5–30GB.
- April rises — on EE, O2, Vodafone and Three a £2.50 rise each April adds about £75 over a two-year plan starting now, as the rises stack.
All matching deals, live
FAQ
Common questions
What is the cheapest unlimited data SIM?
The first row of the table — the lowest 24-month cost today, with rises included.
Can I use unlimited data as home broadband?
Some people do, but fair use rules on tethering often apply. Look at 5G home broadband for a dedicated plan.
Is there a 30-day unlimited SIM?
Yes — several networks sell unlimited on 30-day plans you can cancel any month.