Last updated: Wednesday 16 September 2026 (Europe/London).
Next update: when iD Mobile reprints its 24-month JSON-LD ladder, EE resets 24-month SIM titles, or Talkmobile adds a true 24-month SKU on talkmobile.co.uk.
By: Switch Editorial Team, Switch Squid Ltd
As of 16 September 2026, the cheapest retailer-verified 24-month SIM-only deal on a brand’s own shop is iD Mobile 10GB at £6 a month — £144 over the full 24 months — on idmobile.co.uk/sim-only-deals (JSON-LD ItemList). Step to iD 30GB at £7 (£168) or 60GB at £8 (£192) if you need more data on the same Three mast with no annual CPI/RPI rise. EE also sells true 24-month SIMs, but the cheapest labelled EE 24-month card I opened today starts at £12 for 25GB — double the monthly pound of iD’s 10GB lock.
I am Switch. I rank 24 month SIM only cheapest UK by total cash across the contract, using retailer own shops only. Rolling plans (SMARTY, VOXI, Talkmobile Flex) and 12-month Talkmobile intros are neighbours for flexibility — they are not 24-month deals. Soft browse on the SIM-only hub is fine; the Get deal buttons below go to live affiliate deepLinks.
What a 24-month SIM-only lock actually buys
A 24-month SIM-only contract is two years of airtime without financing a handset. You keep your unlocked phone, take a PAC (or Text to Switch), and pay a lower monthly pound than many 12-month or rolling twins for the same data label — in exchange for early-exit risk if you leave early. iD Mobile’s own FAQ schema (fetched 16 September 2026) states SIM-only plans have no annual CPI or RPI price rises for the contract duration. That matters: many big-network 24-month SIMs still print pounds-and-pence “T” rises in March. Always read the order journey.
Rank by 24-month total cash, not the teaser month. For flat plans that is simply £/mo × 24. For “6 months half price” SKUs, add six months at half rate plus eighteen at full rate — and confirm the half-price window still sits on the live card before you buy.
Ranking table — 16 September 2026 (true 24-month own-shop only)
| Rank | Deal (own shop) | £/mo list | 24-month cash | Catch / network |
|---|---|---|---|---|
| 1 | iD Mobile 10GB 24 Months | £6.00 | £144.00 | Three; no annual rise (iD FAQ) |
| 2 | iD Mobile 30GB 24 Months | £7.00 | £168.00 | Three; flat |
| 3 | iD Mobile 60GB 24 Months | £8.00 | £192.00 | Three; flat |
| 4 | iD Mobile 100GB 24 Months | £10.00 | £210.00 | 6 months half price → 6×£5 + 18×£10 |
| 5 | iD Mobile 150GB 24 Months | £12.00 | £252.00 | 6 months half price |
| 6 | iD Mobile 250GB 24 Months | £14.00 | £294.00 | 6 months half price |
| 7 | EE SIM 25GB 24m | £12 | £288.00* | EE mast; confirm “T” rises at checkout |
| 8 | iD Unlimited 24 Months | £16.00 | £384.00 | Flat; Three |
| 9 | EE SIM 50GB 24m | £14–£16 | £336–£384* | Title variants on ee.co.uk; checkout gospel |
| 10 | EE SIM 150GB 24m | £21 | £504.00* | EE; heavier data |
*EE 24-month monthly titles from ee.co.uk/mobile/sim-only-deals NEXT_DATA on 16 September 2026; mid-contract rise months can lift total cash above list × 24 — re-check the bill plan before you lock.
Sources: iD Mobile JSON-LD ItemList on idmobile.co.uk/sim-only-deals (23 products including seven 24-month rows); EE SIM-only NEXT_DATA plan titles; Talkmobile and SMARTY own shops for the “not 24-month” neighbour section below.
Get deal — iD 24-month SIM cards →
Why iD owns the 24-month cash lead today
Six pounds times twenty-four is £144. No other own-shop 24-month SIM I verified this morning undercuts that total for a labelled data plan with unlimited UK minutes and texts. iD sits on Three’s network, so coverage is Three-shaped — check Ofcom’s checker and your own kitchen signal before you celebrate the pound. Data rollover and bill capping remain iD product features on many plans; read the live card for the SKU you pick.
The half-price 100/150/250GB 24-month rows look loud on a tile. Once you annualise the promo correctly they still lose to the flat £6 / £7 / £8 ladder on total cash unless you actually need that much data. Do not buy 250GB because the “half price” badge feels clever — buy the allowance you used last month plus a small buffer.
EE 24-month SIMs — real locks, higher cash
EE’s own SIM-only page still sells flexible 30-day and 24-month plans on the EE mast. The 24-month titles I scraped today include SIM 25GB at £12, SIM 50GB at £14/£16 depending on the card cluster, SIM 150GB at £21, Essentials Unlimited Max around £23, and Full Works at £36. Those are fine products if you need EE coverage or EE extras — they are not “cheapest 24-month” winners against iD’s £6 10GB. EE also prints mid-contract price-rise language on many SIMs; treat list × 24 as a floor until checkout confirms the rise schedule.
Neighbours that are not 24-month (label honestly)
- SMARTY — Classic plans via smarty.co.uk/api/v1/plans are rolling (
length: null). 2GB/500MB at £5, 5GB at £6. Great flexibility; zero 24-month lock. - Talkmobile — JSON-LD shows 12-month (100GB intro then £9.95; 150GB intro then £11.95) and 30-day Flex from £5.95. No 24-month SKU on the shop page fetched today.
- VOXI — youth Vodafone brand; rolling / pass model; no 24-month ladder in the plans HTML.
- Lebara — prepaid-style international calling strength; not ranked as a 24-month post-pay lock here.
- O2 — shop returned a Waiting Room page this morning; not priced without a clean own-shop grid.
If you want month-to-month freedom, stop reading 24-month leaderboards and compare rolling cash instead. Locking two years only wins when the monthly discount beats the flexibility cost and you are sure about coverage.
How to choose length without regret
- Check last month’s data use in your current app.
- Run Ofcom coverage for Three (iD) vs EE at home and work.
- On iD, prefer flat £6–£8 24-month rows unless you truly need 100GB+.
- On EE, open the bill-plan PDF / order journey and diary every March rise.
- Port with a PAC; do not cancel the old SIM until the new one is live.
Soft look at the wider market on the SIM-only deals hub — primary Get deal stays on the affiliate deepLink.
eSIM, PAC and testing coverage before you lock
Most iD and EE 24-month SIMs offer eSIM on compatible handsets. That means you can keep a physical SIM for banking OTPs while you trial coverage, then port the number once you are happy. Text PAC to 65075 on the old line (or use Text to Switch) and do not cancel until the port completes — usually within one working day once the new network accepts the code.
A cheap 1-month Three or iD rolling SIM is still the smartest “coverage probe” if you have never lived on Three’s mast. Two years at £6 is only a bargain if the signal in your bedroom and office is usable. Ofcom’s mobile coverage checker is the public map; your own speed tests at 8pm are the truth.
When a 12-month or rolling plan still wins
Students, renters with a six-month break clause, and anyone expecting an employer handset should not romanticise a 24-month discount. Talkmobile’s 12-month intros and SMARTY’s rolling Classic ladder exist for that reason. Annualise them honestly (include the post-intro months on Talkmobile) and compare to iD’s £144 / £168 / £192 24-month totals. If the gap is only a few pounds a month and your life is unstable, pay for flexibility.
Also watch handset financing separately. A “free phone” 24-month airtime+device contract is a different product from SIM-only — this page ranks airtime locks only.
Get deal — live 24-month SIM offers →
FAQ
What is the cheapest 24 month SIM only deal in the UK on 16 September 2026?
iD Mobile 10GB 24 Months at £6 (£144 over 24 months) on idmobile.co.uk, verified via the shop’s JSON-LD ItemList. iD 30GB at £7 (£168) and 60GB at £8 (£192) are the next steps on the same ladder.
Does iD Mobile raise 24-month SIM prices every year?
iD’s own FAQ schema says SIM-only plans have no annual CPI or RPI price rises for the contract duration. Still read the order confirmation for your SKU.
Are SMARTY or Talkmobile 24-month deals?
Not on the shops I opened today. SMARTY is rolling; Talkmobile lists 12-month and 30-day contracts only. Do not treat their monthly £ as a 24-month total.
Is EE cheaper than iD for 24-month SIMs?
Not on cash for light/mid data. EE’s cheapest labelled 24-month SIM title today was 25GB at £12 (£288 list × 24 before any rises) — higher than iD’s £6 10GB and £7 30GB.
How do I calculate 24-month cash on a half-price promo?
Add the discounted months at half rate to the remaining months at full rate. Example: iD 100GB 24 Months at £10 with 6 months half price → 6×£5 + 18×£10 = £210.
Can I leave a 24-month SIM early?
Usually you owe the remaining months or an exit fee — check the specific contract. If you might move abroad or change handset plans soon, prefer 1-month or 12-month.
Whose network is iD Mobile on?
Three UK. Coverage and 5G follow Three’s footprint. Test signal before you lock two years.
Should I pick unlimited on a 24-month deal?
Only if you tether or stream heavily. iD Unlimited 24 Months at £16 is £384 over the term — fine for heavy use, poor value if you sit under 30GB.
Get deal — compare live SIM cards →
Prices and plan names change. Always confirm on the retailer’s own checkout on the day you buy. Affiliate links (Awin 911601) may earn SwitchSquid a commission at no extra cost to you.
