Last updated: Thursday 27 August 2026 (Europe/London).
Next update: when Talkmobile, iD Mobile or SMARTY change the 100GB / 108GB monthly rate, or when the live SIM hub shows a cheaper 12-month total.
By: Switch Editorial Team, Switch Squid Ltd
I am Switch. I compare SIMs for a living, and 100GB is the search our own hub cannot rank for without lying about what the page is.
/mobile/sim-only-deals/ is every network, every allowance, ranked by total monthly cost. This page is one tier: 100GB SIM only deals UK, priced on Thursday 27 August 2026. If you already know you want 100GB, start there and filter. If you want the maths before you click, stay here.
I will not rewrite the hub. I will not invent a cheapest-from. Talkmobile’s own site and the comparison tables still disagree on the rolling 100GB rate. The 12-month average is the number I can stand behind.
Filter 100GB on the hub
Compare live SIM only deals. Set data to 100GB, pick 30-day or 12-month, sort by total monthly cost. Commission does not move a row.
Need a new handset instead of airtime? That is a different bill: phone deals.
What I verified today
SwitchSquid’s SIM hub did not render a live deal table in this morning’s fetch, so every pound below is dated to the page I actually opened.
Talkmobile, direct, talkmobile.co.uk/sim-only, 27 August 2026:
100GB, 12 months: £4.98 a month for the first three months, then £9.95 from 26 November 2026. Unlimited UK minutes and texts. 5G. Roaming in 47 European destinations, 5GB fair use.
100GB, 30-day rolling: £9.95 a month. Same extras.
80GB, 30-day: £8.95. Same extras. That is not 100GB.
Twelve months of the 12-month plan is £4.98 × 3 + £9.95 × 9 = £104.49, which is £8.71 a month. That is the cheapest 100GB total I can verify on a network’s own site today. It is not the rolling price.
uSwitch, deals last updated 27/08/2026 unless I say otherwise:
iD Mobile 108GB, 1 month: £9.00. Unlimited minutes and texts. Roam up to 30GB in 50 destinations. Data rollover. (iD silo, 27/08/2026.)
SMARTY 100GB, 1 month: £10.00 on uSwitch. SMARTY’s own 100GB page today is £12.00. Both are 30-day, no credit check, no annual rise, EU roam up to 12GB. I am not going to pretend those two pounds are the same deal.
Lebara 100GB, no contract, uSwitch exclusive: £4.78 for three months, then £11.95. Roam up to 30GB in 37 destinations. On the generic SIM hub today; the Lebara silo itself still said last updated 13/08/2026.
VOXI 100GB, no contract: £12.00. Unlimited social media. Roam up to 20GB in 4 destinations. VOXI silo last updated 26/08/2026.
iD’s 120GB 12-month on uSwitch today is £2.25 for three months, then £9.00. That is 20GB more than the search, so it is not in the 100GB ranking. If the hub shows it when you filter 100GB+, look at the 12-month total, not the teaser.
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.
Plan (dated 27 Aug 2026) | Term | Ongoing £ / month | 12-month average |
|---|---|---|---|
Talkmobile 100GB (talkmobile.co.uk today) | 12 months | £9.95 from 26 Nov 2026 | £8.71 (£104.49 total) |
iD Mobile 108GB (uSwitch 27/08) | 30-day | £9.00 | £9.00 (£108 total) |
SMARTY 100GB (uSwitch 27/08) | 30-day | £10.00 on uSwitch; £12.00 on smarty.co.uk | £10.00 or £12.00 |
Lebara 100GB exclusive (uSwitch hub 27/08) | No contract | £11.95 after month 3 | £10.16 (£121.89 total) |
Talkmobile 100GB rolling (talkmobile.co.uk today) | 30-day | £9.95 | £9.95 (£119.40 total) |
VOXI 100GB (uSwitch 26/08) | No contract | £12.00 | £12.00 (£144 total) |
£4.98 is three months. £8.71 is the year.
Lebara’s £4.78 is the lowest first-month figure on that table. Stay a year and you have paid more than Talkmobile’s 12-month 100GB and more than iD’s 108GB. Rank by total monthly cost, not the teaser.
I did not put a “from £8.95” badge on this page. MyMobiles still listed Talkmobile 100GB rolling at £8.95 when it last checked 27 August 2026. SmartphoneChecker’s 100GB URL had the same £8.95 at 20:00 on 26 August. Talkmobile’s own site this morning is £9.95. uSwitch’s Talkmobile silo still showed £8.95, last updated 10/08/2026. Until the hub and the network print the same rolling pound, I will not make it the headline.
MoneySuperMarket’s Talkmobile page was blocked by Cloudflare this morning. I am not recycling a May 2026 MSM snippet as a Thursday price.
12 months is the cheap 100GB. Rolling is the exit.
The 12-month Talkmobile plan is £1.24 a month cheaper than iD’s rolling 108GB, if you keep it for a year. It is £1.24 a month cheaper than Talkmobile’s own rolling 100GB. The catch is the catch: leave before month 12 and you will usually owe the rest.
Rolling is for three jobs.
You are not sure the mast works at home. Thirty days, then a PAC, then someone else.
You might need a handset in three months. A 12-month SIM plus an early termination fee is a stupid way to buy a phone. Compare phone deals first if the handset is the point.
You want to hop when a new-customer teaser appears. That only works if you actually hop.
If you already know you want Vodafone coverage and 100GB for a year, the Talkmobile 12-month average of £8.71 is the bill I would sign. If you want Three coverage and the right to leave, iD at £9.00 for 108GB is the cleaner rolling number I saw today.
SMARTY at £10 on uSwitch, £12 direct, is the no-credit-check, no-price-rise version of the same Three mast. Pay the extra if you want the brand’s one-month simplicity in writing on their own site. Do not pay it by accident because you skipped the comparison card.
100GB is not the average. That is the point.
uSwitch’s SIM hub, updated today, cites Ofcom’s 2026 Communications Market Report: a typical UK mobile user uses 11.8GB a month. 100GB is roughly eight times that. Most people searching 100GB are not average. They are doing one of these:
Hotspot a laptop because the Airbnb Wi-Fi is a rumour.
Commute on data, not station Wi-Fi.
Share a phone as a tablet for a kid.
Work on the train and refuse to think about a 20GB cap.
Came off a 24-month 100GB handset contract and want the same allowance without the phone finance.
If your iPhone Settings → Mobile Data (or Android’s data usage) shows 15GB last month, you are shopping the wrong tier. The hub will show 20GB and 50GB rows that undercut everything on this page. I am not going to pretend 100GB is virtuous. It is insurance, tethering, and habit.
If last month was 70GB and you still have two weeks to go, 100GB is the right search. Unlimited is the next conversation, not this one.
80GB, 100GB, unlimited
Same day, same shops. This is why 100GB exists as a keyword: it sits in a gap, and the gap is small.
If last month was 15GB, stop shopping 100GB.
Allowance | Example I verified | £ / month | Gap vs 100GB |
|---|---|---|---|
80GB | Talkmobile 30-day (talkmobile.co.uk, 27 Aug) | £8.95 | £1 less than Talkmobile’s own 100GB rolling (£9.95) |
~100GB | iD 108GB rolling (uSwitch 27/08) | £9.00 | — |
100GB | Talkmobile 12-month average (talkmobile.co.uk, 27 Aug) | £8.71 | Cheapest 12-month total on this page |
Unlimited | iD unlimited rolling (uSwitch 27/08) | £15.00 | £6 more than iD 108GB |
£1 is 20GB on Talkmobile rolling, on their own site today. If you never tether, take the 80GB and stop reading. If you hotspot a laptop twice a week, do not cheap out for a pound and then buy a bolt-on.
£6 is the step from iD 108GB to iD unlimited. Unlimited is not “free extra”. It is a fair-use policy and a higher bill. iD’s own unlimited on uSwitch today is £15 rolling, or £8 for three months then £16 on 12 months. SMARTY unlimited is £17 rolling on uSwitch today; SMARTY’s own unlimited page still prints £20. uSwitch already has a dedicated unlimited URL. I am not writing it again.
VOXI at £12 for 100GB looks dear next to £9. It is less daft if you actually use their data-free social apps. That perk does not travel: uSwitch’s VOXI page (26/08) says social and streaming extras do not apply while roaming, and EU roaming is £2.45 a day, not bundled like Talkmobile or iD. Date that before a holiday.
You are buying a mast, not a logo
100GB on a dead mast is 0GB. The four UK networks still sit under the MVNO names.
If you want this mast | 100GB-ish plan I named today | Parent | Check before you pay |
|---|---|---|---|
Vodafone | Talkmobile 100GB; Lebara 100GB; VOXI 100GB | Vodafone | Ofcom checker at home and work |
Three / VodafoneThree | iD 108GB; SMARTY 100GB | Three | Same checker. Rural Three still varies |
O2 | None at 100GB that I verified today | O2 | Do not invent a giffgaff 100GB |
EE | None at 100GB that I verified on EE or a named EE MVNO today | EE | Filter the hub; I will not guess a pound |
Talkmobile, Lebara and VOXI all ride Vodafone. Coverage should match. Price, roaming and the right to leave will not.
iD and SMARTY ride Three. uSwitch’s iD 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 100GB from EE, O2, Tesco Mobile, Sky or giffgaff on the pages I opened this morning. The hub may have them by this afternoon. If it does, they will sort by total cost. I am not filling the gap with a memory.
Roaming is not your 100GB
UK 100GB does not follow you to Spain as 100GB. The caps I actually saw:
Network | Roaming I saw | Data cap abroad | Dated |
|---|---|---|---|
Talkmobile | 47 European destinations, included | 5GB fair use | talkmobile.co.uk, 27 Aug |
iD Mobile | 50 destinations, included | 30GB fair use | uSwitch iD, 27/08 |
SMARTY | EU, included | 12GB, then a top-up | smarty.co.uk and uSwitch, 27 Aug |
Lebara | 37 destinations, included | Up to 30GB on the 100GB plan | uSwitch hub, 27/08 |
VOXI | Not bundled like the others | 20GB in 4 destinations at £2.45/day (uSwitch) | VOXI silo, 26/08 |
A week in Europe on Talkmobile can burn the 5GB roam cap while 95GB sits unused at home. iD’s 30GB roam is the reason I would pick £9 over Talkmobile rolling £9.95 if I had a trip booked. If you never leave the UK, ignore this table and take the 12-month average.
If the phone is the problem
100GB 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 100GB 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 Thursday live card. I am not reprinting £262 as today’s saving.
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.
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. A 12-month 100GB is a bad surprise if you still owe six months on a handset plan.
eSIM: SMARTY and iD both flagged eSIM on the uSwitch cards I opened today. Talkmobile’s own FAQ says eSIM is available on compatible devices. 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. Talkmobile’s own FAQ, today, no credit check on SIM only. uSwitch’s iD FAQ still says iD SIM only plans involve a credit check, with PAYG as the fallback. I am not going to flatten that into “MVNOs never check”. Read the card.
No mid-contract rise: Talkmobile’s own 100GB pages, SMARTY, iD and Lebara all sell that as a feature. The big four still tend to put an April rise on longer SIMs. If you sign 12 months with a brand that rises in April, the £8.71 average is not the year-two bill.
What I want you to do
Open the SIM only hub. Filter 100GB. If you are happy on Vodafone and you will stay a year, the Talkmobile 12-month average of £8.71 (priced on their site, 27 August 2026) is the total to beat. If you want Three and an exit, iD 108GB at £9.00 rolling (uSwitch, 27/08/2026) is the rolling total to beat. If the hub shows cheaper same-day, take the hub. We rank by total monthly cost, not by commission.
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 100GB SIM only deal in the UK today?
The cheapest 100GB total I can verify on a network site on 27 August 2026 is Talkmobile’s 12-month 100GB: £4.98 a month until 26 November 2026, then £9.95, which is £8.71 a month over 12 months (£104.49). The cheapest rolling ~100GB I can verify same-day on uSwitch is iD Mobile 108GB at £9.00. I am not headlining Talkmobile rolling at £8.95 while talkmobile.co.uk prints £9.95.
Is 100GB enough, or should I get unlimited?
Most people do not use 100GB. Ofcom’s 2026 figure, via uSwitch today, is 11.8GB average. Take 100GB if you tether, commute on data, or came off a 100GB phone contract and liked the headroom. Take unlimited if you already blow past 80–90GB. iD unlimited was £15 rolling on uSwitch today, £6 above their 108GB.
Why is 108GB in a 100GB article?
Because iD does not currently sell a card labelled 100GB on the uSwitch page I opened. 108GB at £9 is the SKU people get when they search 100GB on Three’s mast. I labelled it 108GB every time I used it.
Is the Talkmobile 12-month 100GB really £4.98?
For three months, yes, on talkmobile.co.uk today. Then £9.95 from 26 November 2026. Networks advertise the teaser. I advertised the average. If you leave at month four you have not banked £8.71.
SMARTY says £12. uSwitch says £10. Which is real?
Both can be, on the same day. uSwitch’s SMARTY 100GB card was £10.00 on 27/08/2026. SMARTY’s own 100GB URL was £12.00 the same morning. Comparison exclusives exist. Checkout is the price. I dated both rather than picking the one that makes a nicer headline.
Does 100GB include hotspot?
On the plans I named, tethering is included. SMARTY’s own 100GB page says you can hotspot with no speed cap in the UK. iD’s uSwitch copy says tethering is allowed on all plans. Talkmobile’s FAQ says the allowance can be shared. Roaming caps still apply abroad.
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 a 100GB SIM?
Not on Talkmobile SIM only or SMARTY, according to their own sites 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, filter that on the hub rather than assuming.
What about 30-day rolling 100GB as a whole category?
Plenty of rolling 100GB exists. This URL is the 100GB shop, not a 30-day explainer. The hub already covers rolling vs 12 vs 24. Rolling 100GB I verified today: Talkmobile £9.95 direct, iD 108GB £9, SMARTY £10 / £12, Lebara £11.95 after the intro, VOXI £12.
Should I buy a phone on contract instead?
Only if you need the handset. Airtime at £9 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 27 August 2026: SIM only deals — 100GB 12-month £4.98 for 3 months then £9.95 from 26 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; no credit check (FAQ); 5G; Wi-Fi calling.
SMARTY, fetched 27 August 2026: 100GB plan — £12.00 rolling; unlimited UK calls and texts; 5G; no credit check; no annual rise; EU roam 12GB fair use; eSIM; tethering uncapped in the UK. Own-site unlimited £20.
uSwitch generic SIM hub, deals last updated 27/08/2026: Compare SIM only deals — Lebara 100GB exclusive £4.78 then £11.95; 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 Thursday card).
uSwitch iD Mobile, deals last updated 27/08/2026: iD SIM only — 108GB £9.00 1 month; 120GB 12-month £2.25 then £9.00; unlimited £15.00 rolling / £8 then £16 on 12 months; roam 30GB in 50 destinations; data rollover; credit-check FAQ.
uSwitch SMARTY, deals last updated 27/08/2026: SMARTY SIM only — 100GB £10.00 1 month; unlimited £17.00 1 month.
uSwitch VOXI, deals last updated 26/08/2026: VOXI SIM only — 100GB £12.00; 80GB £10.00; 140GB £15.00; unlimited £35.00; EU roam £2.45/day; social extras off while roaming.
uSwitch Lebara silo, deals last updated 13/08/2026 (cards also on the 27/08 hub): Lebara SIM only — 100GB £4.78 then £11.95; unlimited £9.98 then £24.95.
uSwitch Talkmobile silo, deals last updated 10/08/2026: still listed 100GB at £8.95 1 month — not treated as a same-day refresh.
MyMobiles, last checked 27 August 2026: SIM-only deals — Talkmobile 100GB rolling £8.95; Talkmobile 100GB 12-month £9.95 (ongoing, no intro on that row); iD 108GB £9.00; VOXI 100GB £12.00. Used as a third-party cross-check, not as SwitchSquid live cards.
SmartphoneChecker, prices last updated 26 August 20:00: 100GB SIM only — Talkmobile 100GB 30-day £8.95; iD 108GB £9. Closest dedicated 100GB competitor URL. Not same-morning.
SwitchSquid, fetched 27 August 2026: SIM only hub — generic SIM explainer, no 100GB slug, live deal table not present in the fetch. Phone deals. Homepage still describes 24-month 100GB SIM as typically £12 to £20/month.
