How to compare SIM-only deals
- Start with your data needs — check 3 months of real usage before choosing an allowance.
- Compare the total contract cost, not just the monthly price: a £10/month 12-month deal costs £120.
- Check what's included: EU roaming, tethering, 5G access and speed caps vary a lot.
- Look at the network underneath: many cheap SIMs run on the big four networks — coverage is what matters.
Traps to avoid
- Introductory prices that jump after 3–6 months — read the full term, not the headline.
- Annual price rises written into the contract (usually CPI + a few percent each April).
- Auto-renewal onto a pricier rolling plan when the term ends — set your own reminder.
- Paying for unlimited data you'll never use — match the plan to your actual usage.
Don't let it auto-renew
The cheapest SIM deal today becomes an expensive one the day it rolls over. Add your plan to UK Bill Tracker — free — and get an email before the contract ends, so you switch to the next cheap deal instead of drifting onto the expensive default.
Track your SIM deal freeFrequently asked questions
Are SIM-only deals cheaper than phone contracts?
Almost always, once you own your phone — you're paying for service, not repaying a handset.
Should I choose 12-month or 30-day?
12-month is cheaper monthly; 30-day rolling gives freedom to switch any time.