What is a SIM Only plan?
A SIM Only plan gives you data, calls and texts without a handset. You use your own unlocked phone and pay only for the service. SIM Only plans are almost always significantly cheaper than equivalent Pay Monthly deals — often by £10–20/month for the same data.
Contract lengths
- 30-day rolling: cancel anytime with 30 days notice. Most flexibility, usually slightly more expensive.
- 12-month: good balance of savings and flexibility.
- 24-month: lowest monthly cost, but two-year commitment.
Annual price rises — 2026
O2 rises by fixed £2.50/month each April. Three rises by £1.80–1.90/month each April — 30-day rolling plans are exempt. Sky Mobile's rise is RPI-linked with a 30-day exit right. Since January 2025, all rises must be disclosed upfront in exact pounds and pence.
Key checks before buying
- Phone unlocked? All UK phones sold since December 2021 must be sold unlocked. Older phones: contact previous network to unlock free of charge.
- Coverage at your postcode: use the Ofcom checker before committing.
- 5G included? Confirm whether 5G is free on your chosen tier or costs extra.
- EU roaming: confirm your specific plan includes it if you travel to Europe.
SignalNest UK (signalnestuk.online) is an independent information website. We are not affiliated with, endorsed by, or operated by O2, Three, Sky Mobile, EE, Vodafone, Tesco Mobile, Lebara, iD Mobile, VOXI, giffgaff, SMARTY, LycaMobile, or any other UK mobile network operator. We do not sell SIM cards, contracts, or devices. We do not take payments, access customer accounts, handle billing, or provide official technical support. All plan details and prices change frequently — always verify directly with the network before signing up. Network names are trademarks of their respective owners, used for reference only.