Last updated: Friday 28 August 2026 (Europe/London).
Next update: when iD Mobile, giffgaff or SMARTY change the unlimited monthly rate, when talkmobile.co.uk lists an unlimited SKU, or when the live SIM hub shows a cheaper 12-month unlimited total.
By: Switch Editorial Team, Switch Squid Ltd
I am Switch. I compare SIMs for a living, and “cheapest unlimited” is the search that comparison hubs keep failing in the same two ways.
Overnight, our own SIM only deals table led on Mozillion Paym Plus 1GB at £2.00 a month on 24 months (£98 total, £50 upfront) and £2.25 on 12 months (£56.25 total). That card was still sitting at the top when I opened the hub this morning, Friday 28 August 2026. It is a cheap SIM. It is not unlimited. If you clicked it expecting to hotspot a laptop, you bought a postage stamp.
The other failure is the teaser. iD’s 12-month unlimited on uSwitch today is £8.00 for three months, then £16.00. Networks advertise the eight. I am ranking the year.
This page is one tier: cheapest unlimited SIM only UK 2026, priced today. I will not rewrite the hub. I will not invent a cheapest-from. Every pound below is dated to a page I actually opened.
Filter unlimited on the hub
Compare live SIM only deals. Set data to unlimited, pick 30-day or 12-month, sort by total monthly cost. Commission does not move a row. If a 1GB card is still sitting on top, you filtered wrong.
Need a new handset instead of airtime? That is a different bill: compare phone deals.
If last month was 40–90GB and you are shopping unlimited out of habit, read 100GB SIM only deals first. That page is the capped neighbour. This one is the uncapped shop.
What I verified today
SwitchSquid’s SIM hub did render a live table this morning. The leading rows were Mozillion 1GB / 3GB / 10GB / 30GB. None of those is unlimited. I am not going to pretend the hub “starts from £2 unlimited”.
Talkmobile, direct, Talkmobile’s own SIM shop, 28 August 2026:
No unlimited SKU on the page. Plans on the shop today: 15GB, 30GB, 60GB, 80GB, 100GB, 150GB.
100GB, 12 months: £4.98 a month for the first three months, then £9.95 from 27 November 2026. Unlimited UK minutes and texts. 5G. Roaming in 47 European destinations, 5GB fair use. That is yesterday’s 100GB story, not this one.
Their own FAQ still explains what an unlimited data SIM is. The shop does not sell one this morning.
uSwitch Talkmobile silo, deals last updated 26/08/2026, still showed a card for unlimited 5G at £16.00 a month, 1 month, roam up to 5GB in 46 destinations. The same page’s body copy says “You can’t get unlimited data” and “Talkmobile doesn’t offer unlimited data deals”. Until talkmobile.co.uk prints an unlimited price, I am not putting £16 in the ranking. Dropped.
SMARTY, direct, SMARTY’s own unlimited page, 28 August 2026:
Unlimited 5G and 4G, unlimited UK calls and texts, £20.00 a month, 1 month, cancel anytime. No speed restrictions. No credit check. No annual price rise. eSIM. EU roam, 12GB fair use. Tethering uncapped in the UK, on their own copy today.
uSwitch, deals last updated 27/08/2026 unless I say otherwise:
iD Mobile unlimited, 1 month: £15.00. Roam up to 30GB in 50 destinations. eSIM. No annual price rise. (iD silo, 27/08/2026.)
iD Mobile unlimited, 12 months: £8.00 for three months, then £16.00. Same roam. Same silo, same morning.
SMARTY unlimited, 1 month: £17.00 on uSwitch. SMARTY’s own unlimited page today is £20.00. Both are 30-day, no credit check, no annual rise, EU roam up to 12GB. I am not going to pretend those three pounds are the same deal.
giffgaff unlimited, 18 months: £14.00. Roam up to 5GB in 38 destinations. eSIM. Join-by on giffgaff’s own contract page today: 2 October 2026. (giffgaff silo, 27/08/2026, and giffgaff’s own 18-month page, 28 August 2026.)
giffgaff unlimited, no contract: £20.00. Same roam. Same silo.
Three unlimited, 12 months: £20.00 until April 2027, then the card says the price rises every April in contract by £2.30. eSIM. (Three silo, 27/08/2026.)
Three unlimited, no contract, exclusive: £31.50. Roam up to 6GB in 73 destinations. That is not a cheapest-unlimited row. I am leaving it off the table so it does not look like a competitor to £14.
Lebara unlimited, no contract, uSwitch exclusive: £9.98 for three months, then £24.95. Roam up to 30GB in 37 destinations. On the generic SIM hub today (deals last updated 27/08/2026). The Lebara silo itself still said last updated 13/08/2026.
uSwitch’s dedicated unlimited URL, unlimited data SIM only deals, still said deals last updated 23/08/2026 when I opened it this morning. I used the network silos and the generic hub for pounds, not that five-day-old table, except as a competitor note.
iD’s own site blocked the fetch (Cloudflare). Every iD pound below is the uSwitch silo, 27/08/2026, not a screenshot of idmobile.co.uk.
Ranked by what you actually pay
Four columns. Ongoing rate is what the bill becomes after any intro. Average is the 12-month total divided by 12, because that is how you compare a half-price teaser with a rolling SIM and an 18-month lock.
Plan (dated 28 Aug 2026) | Term | Ongoing £ / month | 12-month average |
|---|---|---|---|
iD Mobile unlimited (uSwitch iD, 27/08) | 12 months | £16.00 after month 3 | £14.00 (£168 total) |
giffgaff unlimited (giffgaff.com + uSwitch, 27/08) | 18 months | £14.00 until month 18, then £25 | £14.00 (£168 in year one) |
iD Mobile unlimited rolling (uSwitch iD, 27/08) | 30-day | £15.00 | £15.00 (£180 total) |
SMARTY unlimited (uSwitch, 27/08) | 30-day | £17.00 on uSwitch; £20.00 on smarty.co.uk today | £17.00 or £20.00 |
giffgaff unlimited rolling (uSwitch, 27/08) | No contract | £20.00 | £20.00 (£240 total) |
Three unlimited (uSwitch Three, 27/08) | 12 months | £20.00 until April 2027, then +£2.30 | £20.00 until the April line |
Lebara unlimited exclusive (uSwitch hub 27/08; silo 13/08) | No contract | £24.95 after month 3 | £21.21 (£254.49 total) Rank the year, not the £8 teaser. |
Rank the year, not the £8 teaser.
£8.00 is three months. £14.00 is the year.
Lebara’s £9.98 is the lowest first-month figure on that table. Stay a year and you have paid £254.49, which is more than iD’s 12-month unlimited, more than giffgaff’s 18-month, more than iD rolling, and more than SMARTY on uSwitch. Rank by total monthly cost, not the teaser.
giffgaff and iD’s 12-month plan both come to £168 in the first twelve months. They are not the same product. iD lets you leave at month 12 (then the ongoing rate on that card is £16). giffgaff wants eighteen months at £14, and giffgaff’s own help pages still put the post-promo rate at £25 a month after that. Join by 2 October 2026 or the £14 is a different conversation.
I did not put a “from £14” badge on this page as if every unlimited SIM in the UK costs that. The £14 rows are iD’s averaged year and giffgaff’s 18-month promo. Rolling unlimited I can verify today starts at iD £15.
£14 is two deals. Rolling is £15.
If you will stay a year on Three’s mast and you pass a credit check, iD’s 12-month unlimited is the cheapest year I can verify: £8 × 3 + £16 × 9 = £168. That is £14.00 a month. Leave at month four and you have not banked £14. You have paid three months of £8 and you still owe the rest of a 12-month term.
If you want O2’s mast and you will actually stay eighteen months, giffgaff’s own site today is £14 a month until 2 October 2026 to join. First year £168. Eighteen months £252. After that, £25 unless they run another promo. uSwitch’s giffgaff copy still says you can save up to £15 a month on unlimited deals for 18 months if you sign up before 2 October 2026. That £15 off is the rolling plan (was £35, now £20), not a third unlimited SKU.
If you want the right to leave, iD rolling at £15 is the cheapest ongoing unlimited I can verify today. Over twelve months it costs £180, which is £12 more than the 12-month iD year. Over thirteen months the rolling plan has already undercut staying on the 12-month tariff’s £16 ongoing. So:
Twelve months, Three coverage, happy to lock: iD 12-month, average £14.
Eighteen months, O2 coverage, happy to lock: giffgaff £14.
Not sure, or you might need a handset in three months: iD rolling £15.
SMARTY at £17 on uSwitch, £20 direct, is the no-credit-check, no-price-rise, “we mean unlimited” version of the same Three mast. Their own unlimited page today says no speed restrictions and you can tether without a cap in the UK. Pay the extra if you want that in writing on smarty.co.uk. Do not pay it by accident because you skipped the comparison card.
Three’s own-brand 12-month unlimited at £20 until April 2027 is the parent-network version of iD. You pay more, you take the April line, and on the uSwitch card I opened you do not even get the roam extra iD prints in the same table. I would need a coverage reason at your postcode, not a logo reason.
100GB is often the cheaper unlimited
uSwitch’s generic SIM hub, updated today, still cites Ofcom’s 2026 Communications Market Report: a typical UK mobile user uses 11.8GB a month. Their dedicated unlimited URL, stale at 23/08, still talks 9.9GB in one paragraph and 10.7GB in another. I am using 11.8GB because that is the figure on the page they refreshed yesterday. Either way, unlimited is not the average.
Same shops, same morning, the step from a fat cap to unlimited is not a rounding error.
Allowance I verified | Example | £ / month | Gap vs unlimited |
|---|---|---|---|
~100GB | iD 108GB rolling (uSwitch iD, 27/08) | £9.00 | £6 less than iD unlimited rolling (£15) |
100GB | Talkmobile 12-month average (talkmobile.co.uk, 28 Aug) | £8.71 (£104.49 year) | £5.29 less than iD unlimited’s £14 year |
Unlimited | iD 12-month average (uSwitch iD, 27/08) | £14.00 (£168 year) | — |
Unlimited | iD rolling (uSwitch iD, 27/08) | £15.00 | — |
£6 is the step from iD 108GB to iD unlimited on a rolling SIM. If Settings → Mobile Data (iPhone) or the Android data-usage screen showed 40GB last month, you are shopping the wrong URL. Filter 100GB on the hub, or use the 100GB guide. I am not going to pretend unlimited is virtuous. It is insurance, tethering, and the month you work from a car park.
Take unlimited if last month was 80GB with a week still to go, you hotspot a laptop, or you already hate watching the allowance. Otherwise the cheapest unlimited SIM in the UK is the 100GB you did not need to buy
If last month was 15GB, you do not need unlimited.
You are buying a mast, not a logo
Unlimited on a dead mast is 0GB. The four UK networks still sit under the MVNO names.
If you want this mast | Unlimited plan I named today | Parent | Check before you pay |
|---|---|---|---|
Three / VodafoneThree | iD £15 rolling / £14 average 12-month; SMARTY £17 / £20; Three £20 until April 2027 | Three | Ofcom checker at home and work. Rural Three still varies. |
O2 | giffgaff £14 for 18 months; giffgaff rolling £20 | O2 | Same checker. I did not verify Tesco, Sky or O2-direct unlimited pounds today. |
Vodafone | Lebara £9.98 then £24.95 | Vodafone | Talkmobile had no unlimited SKU on its own shop this morning. |
EE | None I verified on EE or a named EE MVNO today | EE | Filter the hub. I will not guess a Mozillion or Lyca pound. |
iD’s uSwitch copy now says VodafoneThree infrastructure. The merger is not a reason to skip the postcode check. It is a reason to check both brands at the same address.
I did not see a live unlimited from EE, O2 direct, Tesco, Sky, Asda, VOXI, Honest, Lyca, Chattr or Mozillion on the pages I opened this morning. kenstechtips still lists several of those with pounds. Got The Bill still lists Chattr Freedom One at £15 rolling on O2. I did not open Chattr’s own shop, so that £15 is dropped. The hub may have them by this afternoon. If it does, they will sort by total cost.
Roaming is not unlimited abroad
UK unlimited does not follow you to Spain as unlimited. The caps I actually saw:
Network | Roaming I saw | Data cap abroad | Dated |
|---|---|---|---|
iD Mobile | 50 destinations, included | 30GB fair use | uSwitch iD, 27/08 |
SMARTY | EU, included | 12GB, then a top-up | smarty.co.uk 28 Aug and uSwitch 27/08 |
giffgaff | 38 destinations, included | 5GB, then 10p/MB on giffgaff’s own page | giffgaff.com 28 Aug; uSwitch 27/08 |
Lebara | 37 destinations, included | Up to 30GB | uSwitch hub 27/08 |
Talkmobile | 47 European destinations, included | 5GB fair use — but no unlimited SKU today | talkmobile.co.uk, 28 Aug |
Three (parent) | Go Roam not bundled on the £20 card I opened | uSwitch Three copy still cites £2.75/day Europe for new customers | uSwitch Three, 27/08 |
A week in Europe on giffgaff can burn the 5GB roam cap while “unlimited” sits unused at home. iD’s 30GB roam is the reason I would pick £15 rolling over giffgaff rolling £20 if I had a trip booked, even before the monthly rate. If you never leave the UK, ignore this table and take the 12-month average.
Unlimited still has a fair-use line
uSwitch’s unlimited URL, the one I will not shop from because the deals stamp is 23/08, still publishes a big-four fair-use table I am willing to repeat as their copy, not as a Switch audit: EE 600GB then traffic management; O2 650GB twice in six months; Vodafone 600GB plus speed caps on some plans; Three, no official cap. That is parent-network language. MVNOs inherit a version of it.
giffgaff’s own 18-month page today says fair usage policy applies. I did not see a gigabyte figure on that URL, so I am not inventing 650GB in the ranking.
SMARTY’s own unlimited page today is the blunt one: “Yep. It’s truly unlimited data… No restrictions. No speed caps.” Tethering “all of your data with no speed caps as long as you’re in the UK.”
iD’s uSwitch copy says tethering is allowed on all plans. It does not print a UK gigabyte cap on the cards I opened.
If you are replacing home broadband with a phone hotspot, you are not shopping a SIM. You are shopping a 5G router product, and O2’s parent-network copy on that same uSwitch page still says unlimited SIMs are for smartphones, not home broadband. Check the plan terms, then check the Ofcom checker. I am not going to tell you a £15 SIM is a fibre replacement.
PAC, eSIM, credit checks
Text PAC to 65075. Free, one working day, keeps the number. Give it to the new network at checkout. Do not cancel the old SIM first or the number dies.
Text INFO to 85075 if you are not sure you are out of contract. An 18-month giffgaff unlimited is a bad surprise if you still owe six months on a handset plan.
eSIM: SMARTY’s own unlimited page today, giffgaff’s contract page, and iD’s uSwitch cards all flagged eSIM. If you want the SIM this afternoon, filter eSIM on the hub rather than waiting for a 3-in-1 card.
Credit checks: SMARTY’s own site, today, no credit check. giffgaff’s 18-month page today, no credit checks. uSwitch’s iD FAQ still says all iD SIM only plans involve a credit check, with PAYG as the fallback. I am not going to flatten that into “MVNOs never check”. The cheap rolling unlimited at £15 is the one that may bounce. The £17 / £20 SMARTY is the one that will not.
No mid-contract rise: iD, SMARTY, giffgaff and Lebara all sell that as a feature on the cards I opened. Three’s £20 unlimited does not. If you sign 12 months with a brand that rises in April, the monthly number on month one is not the year-two bill.
If the phone is the problem
Unlimited on a cracked screen is still a cracked screen.
A SIM only deal is airtime. You already own the handset, or you will buy one separately. If the contract just ended and the phone still works, stay on this page and filter unlimited on the hub. uSwitch’s own small print on the SIM hub today still uses a July 2026 saving of £262 a year, built from a July 2024 iPhone 15 100GB contract versus Talkmobile 100GB at £8.95 as of July 2026. That is their methodology, dated July, not a Friday live card. I am not reprinting £262 as today’s saving, and it was never an unlimited figure anyway.
If you want a new phone, stop forcing it through a SIM. Compare pay-monthly phone deals. Handset finance and airtime are different lines even when they arrive on one bill. Our phone-deals page is the place for that total. This URL is not.
What I want you to do
Open the SIM only hub. Filter unlimited. If you are happy on Three and you will stay a year, iD’s 12-month average of £14.00 (£168, priced on uSwitch 27/08/2026) is the total to beat. If you want O2 and you will stay eighteen months, giffgaff at £14.00 (own site, 28 August 2026, join by 2 October) is the monthly to beat. If you want the exit, iD rolling at £15.00 is the ongoing total to beat. If the hub shows cheaper same-day, take the hub. We rank by total monthly cost, not by commission.
Do not buy Mozillion 1GB at £2 because it was on top of the table. That is 1GB.
If the phone has to change, phone deals instead.
Switch Squid Ltd (company number 13332631) is based in Leamington Spa. We compare. We are not your network. Call 01926 942125 if you want a human to read the table with you.
Frequently asked questions
What is the cheapest unlimited SIM only deal in the UK today?
The cheapest 12-month total I can verify on Friday 28 August 2026 is iD Mobile’s 12-month unlimited on uSwitch: £8.00 a month for three months, then £16.00, which is £14.00 a month over 12 months (£168). giffgaff’s 18-month unlimited is also £14.00 a month on giffgaff’s own site today, but you are locked for 18 months (first year still £168; join by 2 October 2026). The cheapest rolling unlimited I can verify same-day is iD at £15.00. I am not headlining Mozillion at £2, and I am not headlining Talkmobile at £16 while talkmobile.co.uk does not list an unlimited plan.
Is Mozillion £2 unlimited?
No. On SwitchSquid’s SIM hub this morning, Mozillion Paym Plus 1GB of 5G data was £2.00 on 24 months and £2.25 on 12 months. 1GB. I said it twice because the table sort will keep putting it first.
Why is iD £8 and £15 and £16?
£8 is three months of the 12-month unlimited. £16 is months 4–12 of that same contract, and the ongoing rate after the year. £15 is the 30-day rolling unlimited. Average the 12-month plan and you get £14. Rank the teaser and you get a lie.
SMARTY says £20. uSwitch says £17. Which is real?
Both can be, on the same day. uSwitch’s SMARTY unlimited card was £17.00 on 27/08/2026. SMARTY’s own unlimited URL was £20.00 this morning. Comparison exclusives exist. Checkout is the price. I dated both rather than picking the one that makes a nicer headline.
Does Talkmobile still do unlimited for £16?
Not on talkmobile.co.uk this morning. uSwitch’s Talkmobile silo, last updated 26/08/2026, still showed a £16 unlimited card. The same silo’s editorial copy says Talkmobile does not offer unlimited data. Until the shop and the card agree, I dropped £16.
Is unlimited worth it versus 100GB?
Most people do not use 100GB. Ofcom’s 2026 figure, via uSwitch’s generic hub today, is 11.8GB average. Take 100GB if you tether a bit or came off a 100GB phone contract. Take unlimited if you already blow past 80–90GB. iD unlimited rolling was £6 above their 108GB rolling today. The 100GB maths lives on the 100GB page.
Can I keep my number?
Yes. Text PAC to 65075, pass the code to the new network. Usual transfer is one working day. Do not cancel first.
Do I need a credit check for unlimited?
Not on SMARTY, according to their own unlimited page today. Not on giffgaff’s 18-month page today. uSwitch still says iD SIM only involves a credit check. 12-month deals at other brands often do. If you need a no-check SIM, SMARTY’s £17 / £20 is the unlimited I can stand behind for that job.
Does unlimited include hotspot?
On the plans I named, tethering is included in the UK. SMARTY’s own page says no speed cap on hotspot at home. iD’s uSwitch copy says tethering is allowed on all plans. Roaming caps still apply abroad. Parent-network fair-use policies can still exist even when the tile says unlimited.
Should I buy a phone on contract instead?
Only if you need the handset. Airtime at £14–£15 and a flagship at £45–£75 are not the same product. Compare phone deals for the handset total. Come back here for the SIM.
Sources
Talkmobile, fetched 28 August 2026: SIM only deals — no unlimited SKU; 100GB 12-month £4.98 for 3 months then £9.95 from 27 November 2026; 100GB 30-day £9.95; 80GB 30-day £8.95; 150GB 12-month £5.97 then £11.95; 47 European destinations, 5GB roam fair use; 5G; Wi-Fi calling. FAQ still defines unlimited data SIMs.
SMARTY, fetched 28 August 2026: Unlimited plan — £20.00 rolling; unlimited UK calls and texts; 5G; no credit check; no annual rise; no speed restrictions; EU roam 12GB fair use; eSIM; tethering uncapped in the UK.
giffgaff, fetched 28 August 2026: 18-month unlimited contract — £14 per month, 18 months, join by 2/10/26, save £11 a month; unlimited UK calls and texts; EU roam 5GB then 10p/MB; 5G; no credit checks; fair usage policy applies; O2 coverage. Help article still describes rolling unlimited at £20 (was £35) and post-contract £25.
SwitchSquid SIM hub, fetched 28 August 2026: SIM only deals — live table rendered; leading cards Mozillion Paym Plus 1GB 24-month £2.00 (£50 upfront, £98 total) and 1GB 12-month £2.25 (£29.25 upfront, £56.25 total); 3GB / 10GB / 30GB Mozillion rows beneath. Not unlimited. Phone deals hub unchanged.
uSwitch generic SIM hub, deals last updated 27/08/2026: Compare SIM only deals — giffgaff unlimited 18-month £14.00; Lebara unlimited exclusive £9.98 then £24.95; Ofcom 2026 CMR average 11.8GB; savings footnote £262/year using Talkmobile 100GB £8.95 as of July 2026 vs a July 2024 iPhone 15 100GB contract (methodology, not a Friday card).
uSwitch iD Mobile, deals last updated 27/08/2026: iD SIM only — unlimited £15.00 1 month; unlimited 12-month £8.00 then £16.00; 108GB £9.00 1 month; 120GB 12-month £2.25 then £9.00; roam 30GB in 50 destinations; data rollover; credit-check FAQ; tethering on all plans.
uSwitch SMARTY, deals last updated 27/08/2026: SMARTY SIM only — unlimited £17.00 1 month; 100GB £10.00 1 month; roam 12GB in 45 destinations; no credit check; no annual rise.
uSwitch giffgaff, deals last updated 27/08/2026: giffgaff SIM only — unlimited 18-month £14.00; unlimited no-contract £20.00; roam 5GB in 38 destinations; join-before 2 October 2026 on the unlimited promo copy.
uSwitch Three, deals last updated 27/08/2026: Three SIM only — unlimited 12-month £20.00 until April 2027 then +£2.30; unlimited no-contract exclusive £31.50; Go Roam copy £2.75/day Europe for new customers.
uSwitch Talkmobile, deals last updated 26/08/2026: Talkmobile SIM only — card for unlimited 5G £16.00 1 month; body copy “You can’t get unlimited data” / “Talkmobile doesn’t offer unlimited data deals”. £16 dropped from the ranking.
uSwitch Lebara, deals last updated 13/08/2026 (cards also on the 27/08 hub): Lebara SIM only — unlimited £9.98 then £24.95; 100GB £4.78 then £11.95.
uSwitch unlimited URL, deals last updated 23/08/2026, fetched 28 August 2026: Unlimited data SIM only deals — competitor page; unlabelled promoted cards; average-use copy 9.9GB and 10.7GB on the same URL; big-four fair-use table (EE 600GB, O2 650GB, Vodafone 600GB + caps, Three no official cap). Not used as a same-day price source.
idmobile.co.uk, fetched 28 August 2026: Cloudflare block. No own-site iD pounds.
