Last updated: Tuesday 1 September 2026 (Europe/London).
Next update: when Lycamobile’s £3.50 first-month offer ends on 30 September 2026, when SMARTY or giffgaff change the 5GB monthly rate, when iD’s 20GB £6 promo ends on 8 September 2026, or when the live SIM hub shows a cheaper same-allowance 12-month total on a retailer page I can open.
By: Switch Editorial Team, Switch Squid Ltd
I am Switch. I compare SIMs for a living, and 5GB SIM only deals UK September 2026 is the search comparison sites keep answering with a 5GB tile that is not on the retailer’s own shop — or with a 5G filter that mixes 5GB, 50GB and unlimited on the same grid.
uSwitch has no dedicated 5GB URL. You land on the generic 5G SIM page or a 30-day hub, tick a box, and hope the card still means 5GB by checkout. This morning Talkmobile’s 5GB tile is still floating around comparison tables. It is not on talkmobile.co.uk. I dropped it. Lebara’s £1.48-then-£4.95 5GB exclusive is the same trick — not on lebara.co.uk. I dropped that teaser. What Lebara’s own shop does sell is a flat 5GB at £5 rolling or £4.50 on 12 months. That shop price is in the table. The comparison teaser is not.
Our SIM only hub is every network and every allowance, ranked by total monthly cost. This page is one tier: 5GB, priced from retailer pages on Tuesday 1 September 2026.
The cheapest cash row is Lebara 5GB at £4.50 on a 12-month toggle on lebara.co.uk — twelve months £54.00. That SKU is 1,000 UK minutes and texts, not unlimited, plus 100 international minutes, Vodafone masts. The honest lead for most people who want unlimited UK calls is still spusu 5 at £4.90 rolling on spusu.co.uk/plans — uncapped 5G, EE masts, twelve months £58.80. Lycamobile’s UK Plan Smart is £58.50 if you take the website-only £3.50 first month then £5. Also 1,000 UK calls and texts, also not unlimited. Different products. I am ranking them, and I am saying so.
Ofcom’s Communications Market Report 2026 puts average monthly data per mobile data user at 11.8GB in 2025 (CMR 2026 PDF). So 5GB is a light-user bucket, not the average. If last month was 8–15GB, you are on the wrong URL — start with 20GB SIM only deals. If it was 40GB-plus, use 100GB or unlimited.
Same-cash warning, because it is the whole point of ranking a thin allowance in September: SMARTY’s 5GB is £6 a month on smarty.co.uk. iD Mobile’s 20GB is also £6 a month on idmobile.co.uk until 8 September 2026 (new customers). Four times the data, same pound, while that promo holds. Do not buy 5GB out of habit if 20GB is the same bill.
I will not invent a 5GB SKU. I will not rank a uSwitch tile the retailer’s own site does not sell. Every pound in the ranking table below is dated to a retailer page I am standing behind on 1 September 2026.
Filter 5GB on the hub
Open the SIM only hub. Set data around 5GB, pick 30-day, sort by total monthly cost. Commission does not move a row. If a 1GB or 20GB card is still sitting on top, you filtered wrong.
Need a new handset instead of airtime? That is a different bill: compare phone deals.
Already sure you want a fatter cap? Neighbour guides are 20GB SIM only deals UK, 100GB SIM only deals UK and cheapest unlimited SIM only UK 2026. This URL stays on 5GB.
What I verified today
Five retailer-verified 5GB plans. Dated Tuesday 1 September 2026 unless I say otherwise. Comparison exclusives that are not on the shop today live in the “What I dropped” section, not here.
Lebara 5GB, lebara.co.uk/en/best-sim-only-deals.html, fetched 1 September 2026: 30-day toggle £5.00, 12-month toggle £4.50 (labelled 10% off). No intro/then teaser on the shop — a single flat price per toggle. 5GB, 1,000 UK minutes and texts, 100 international minutes. No credit checks, no annual price hikes. Vodafone masts. EU and India roaming on the page copy (comparison table on the same URL says free EU roaming up to 30GB — confirm the 5GB fair use at checkout). Twelve-month total on the 12-month toggle: £54.00, average £4.50. Rolling year at £5 is £60.00. This is the cash lead if you will lock 12 months and stay inside 1,000 UK calls.
spusu 5, spusu.co.uk/plans and spusu.co.uk/spusu5, fetched 1 September 2026: £4.90 a month rolling. 5GB, unlimited minutes, unlimited texts. EU and Switzerland roam 3GB / 500 minutes / 500 SMS. Uncapped 5G. eSIM, VoLTE, Wi-Fi calling. No credit check. EE masts. Twelve-month total £58.80, average £4.90. This is the lead for anyone who wants unlimited UK calls.
Lycamobile UK Plan Smart, lycamobile.co.uk UK Plan Smart, fetched 1 September 2026: £3.50 first month, then £5.00, new customers through the website, offer 20 July–30 September 2026, not in store. 5GB, 1,000 UK calls and texts (not unlimited), 100 international minutes, EU roaming with a 5GB data cap. Lyca’s own page still walks you through 4G APN settings and says 5G is on its way. Twelve-month total £3.50 + 11 × £5.00 = £58.50, average £4.88. Cheaper than spusu by 30p. Not cheaper than Lebara’s 12-month shop price. Different product.
SMARTY 5GB, smarty.co.uk/plans/5gb-data (homepage and all-plans both match), 1 September 2026: £6.00 a month rolling, unlimited UK calls and texts, eSIM, Three network, no annual price rises, EU roaming with a 12GB fair-use line on SMARTY’s 5GB page. Twelve-month total £72.00, average £6.00.
giffgaff 5GB Golden Goodybag, giffgaff £8 Golden Goodybag, research-verified 1 September 2026 (live fetch blocked by giffgaff’s bot wall): £8.00 a month rolling, 5GB, unlimited UK calls and texts, O2 masts, EU roam up to 5GB. Twelve-month total £96.00, average £8.00. Reopen the URL before you treat the pound as gospel after this morning.
What I dropped
Comparison hubs still try to sell these as 5GB. Retailer shops do not, or I could not match the pound on the shop today. I am naming them so you know I looked.
Talkmobile 5GB £4.95 on uSwitch — not on talkmobile.co.uk. The shop’s cheapest rolling SKU this morning is 15GB at £5.95, then 30GB at £6.95. That is 15GB. It is not in the 5GB ranking.
Lebara 5GB £1.48 then £4.95 on uSwitch — comparison exclusive. A full scan of lebara.co.uk this morning found no £1.48 and no £4.95. The shop price is £5 rolling / £4.50 on 12 months. I ranked the shop. I dropped the teaser.
iD Mobile 5GB — no 5GB SKU. PAYG on idmobile.co.uk is 1GB £6, 4GB £8, 6GB £10. Contract promo cards start at 12GB / 20GB. Nearest neighbour is the 20GB £6 promo (to 8 Sept), which is 20GB, not 5GB.
VOXI — no 5GB. Cheapest live plan on voxi.co.uk is the £10 social-unlimited lane (60GB promo to 30 Sept, then 20GB). Wrong URL.
Tesco Mobile — 2GB is the cheap rung on comparison silos, not 5GB. Not ranked here.
If a tile is cheaper than Lebara’s shop £4.50 and the retailer’s own site does not print that SKU, the tile is not a deal. It is a trap for people who do not click through.
Ranked by what you actually pay
Four columns. Ongoing rate is what the bill is while the current promo or rolling rate holds. Average is the 12-month total divided by 12. Every row below is retailer-verified on 1 September 2026 except giffgaff, which is research-verified the same morning.
Plan (dated 1 Sep 2026) | Term | Ongoing £ / month | 12-month average |
|---|---|---|---|
Lebara 5GB 12-month (lebara.co.uk, 1,000 UK mins/texts, 10% off toggle) | 12-month | £4.50 flat | £4.50 (£54.00 total) |
Lycamobile UK Plan Smart 5GB (lycamobile.co.uk, 1,000 UK calls/texts, £3.50 then £5, to 30 Sept) | 30-day, website new customers | £5.00 after month 1 | £4.88 (£58.50 total) |
spusu 5 (spusu.co.uk/plans, unlimited mins/texts, uncapped 5G) | Rolling | £4.90 flat | £4.90 (£58.80 total) |
SMARTY 5GB (smarty.co.uk 5GB plan, unlimited mins/texts, Three) | Rolling | £6.00 | £6.00 (£72.00 total) |
giffgaff 5GB Golden Goodybag (giffgaff.com, research-verified 1 Sep) | Monthly rolling | £8.00 | £8.00 (£96.00 total) |
£4.50 is the Lebara 12-month month. £54 is that year. £4.90 is the unlimited-calls month. £58.80 is that year.
Over twelve months Lebara’s 12-month toggle is £54.00. Lycamobile is £58.50. spusu is £58.80. Lebara and Lyca both cap UK calls at 1,000. spusu does not. SMARTY at £6 is £72 — about £13 more than spusu for Three coverage, eSIM and SMARTY’s own checkout. giffgaff at £8 is £96 — the O2-mast tax at this tier, £37 more than spusu for the year. Lebara rolling at £5 is £60 for the year if you will not lock 12 months — still cheaper cash than SMARTY, still not unlimited calls.
Lebara’s old teaser maths (£1.48 × 3 + £4.95 × 9 = £48.93) would have looked six pounds cheaper than the shop’s 12-month toggle. It is not on lebara.co.uk this morning. I ranked £4.50. I am not putting a ghost SKU above a live retailer price.
Purple nano SIM going into a phone — 5GB SIM only deals ranked by 12-month cash.
£4.90 is the unlimited-calls year
If EE coverage works at your postcodes and you want unlimited UK calls and texts on a rolling SIM, the cheapest retailer-verified 5GB year I can print today is spusu 5 at £4.90 × 12 = £58.80 on spusu.co.uk. No promo clock on that SKU this morning. No 24-month lock.
If you want the absolute lowest cash and you will lock 12 months on 1,000 UK minutes, Lebara’s shop 12-month toggle at £4.50 is £54 for the year on lebara.co.uk. Rolling Lebara 5GB is £5 / £60 a year. Lycamobile’s website-only first month at £3.50 then £5 is £58.50 for the year if you want EE masts instead of Vodafone. Offer ends 30 September 2026, new customers, not in store. After month one you are on £5. After 30 September, reopen lycamobile.co.uk before you treat £3.50 as live.
If you want SMARTY’s no-drama Three option — unlimited UK calls and texts, eSIM, cancel anytime — £6 rolling is the direct price. Fair if you want that brand. Not fair if you only looked at a comparison teaser that is not on the retailer. And not fair if you could still join iD’s 20GB at the same £6 before 8 September.
giffgaff at £8 is the O2-mast rolling Goodybag. Fine if O2 is the only mast that works in your building. Expensive if you are only here because a comparison grid sorted by “from” price.
5GB is below the average. Check Settings first.
Ofcom’s 2026 CMR figure is 11.8GB average per mobile data user in 2025. A 5GB SIM is less than half that average. This URL is for people who live on Wi-Fi, use maps and WhatsApp on the commute, and do not stream video on mobile data.
Illustrative only, labelled as such: at a rough 3GB per hour for HD streaming, 5GB is about ninety minutes of video a month. Maps, social apps and app updates eat the rest. If Settings → Mobile Data (iPhone) or the Android data-usage screen showed 6–10GB last month, 5GB will run out. If it showed 2–4GB with a week still to go, you are in the right shop.
Phone data usage at 3.4GB of a 5GB cap.
I am not going to pretend 5GB is “plenty for everyone”. Ofcom’s average user would hit the wall before mid-month. That is why the 20GB page exists, and why iD’s £6 20GB promo is sitting in the same price band as SMARTY 5GB.
Same £6 as SMARTY 5GB buys 20GB on iD until 8 Sept
This is the September-specific trap. SMARTY 5GB is a clean £6 rolling on Three. iD Mobile’s 20GB promo is also £6 on Three until 8 September 2026, new customers, on 1-month, 12-month and 24-month terms when I last stood on idmobile.co.uk. Same network family. Four times the data. Same monthly pound while the promo holds.
If you actually use 5GB, SMARTY is the simpler Three checkout. If you think you use 5GB because that is what a comparison filter offered, open last month’s usage first. Crossing 5GB on SMARTY means buying add-ons at £1 per GB. Crossing nothing on iD 20GB means you already paid for the headroom.
The 20GB ranking lives on its own URL. I am not stuffing iD 20GB into this table. It is 20GB. It is the reason not to treat 5GB as the default cheap SIM.
You are buying a mast, not a logo
5GB on a dead mast is 0GB. The four UK networks still sit under the MVNO names.
If you want this mast | 5GB plan I named today | Parent | Check before you pay |
|---|---|---|---|
EE | spusu 5 £4.90 (unlimited-calls lead); Lycamobile UK Plan Smart £3.50 then £5 | EE | Ofcom checker at home and work. Lyca 5GB is 1,000 mins/texts and 4G-first on their own page. spusu is uncapped 5G. |
Three | SMARTY 5GB £6 | Three | Rural Three still varies. Same £6 as iD 20GB promo to 8 Sept — do not buy 5GB by habit. |
O2 | giffgaff 5GB Golden Goodybag £8 | O2 | Research-verified 1 Sep on giffgaff’s Goodybag URL. Confirm at checkout. |
Vodafone | Lebara 5GB £4.50 12-month / £5 rolling on lebara.co.uk | Vodafone | Shop price, not the uSwitch £1.48 teaser. Talkmobile shop still starts at 15GB £5.95 — no 5GB SKU. |
Coverage beats £4.80 saved. Run Ofcom’s Map Your Mobile checker for the address you sleep at and the address you work at before you celebrate £54.
When to step up to 20GB, 100GB or unlimited
Stay on 5GB if last month was under about 4GB and you do not hotspot a laptop. Step to 20GB if you sit near 5–15GB or you can still grab iD at £6 before 8 September. Step to 100GB if you regularly clear 20GB. Unlimited is insurance for 80GB+ months, not virtue.
Same morning context, not 5GB rows:
20GB ranking: 20GB SIM only deals UK August 2026 — iD £6 lead while the promo holds.
Talkmobile 100GB and other fat-cap maths live on the 100GB guide.
Unlimited ranking: cheapest unlimited SIM only UK 2026 — year averages, not Mozillion 1GB at £2.
I am not going to flatten those into this page’s table. Different search. Different bill.
Roaming at 5GB
UK data does not follow you abroad as the same allowance. Caps I am dating from the retailer-verified cards today:
Plan | Roaming I saw | Data abroad | Dated |
|---|---|---|---|
spusu 5 | EU and Switzerland | 3GB / 500 mins / 500 SMS | spusu.co.uk/spusu5, 1 Sep 2026 |
Lycamobile UK Plan Smart | EU included on the plan page | 5GB data cap | lycamobile.co.uk, 1 Sep 2026 |
SMARTY 5GB | EU (SMARTY 5GB page) | 12GB fair-use line on that page | smarty.co.uk/plans/5gb-data, 1 Sep |
giffgaff 5GB Goodybag | giffgaff EU / destinations list | Up to 5GB roam like at home | research-verified 1 Sep |
Lebara 5GB | EU and India on the shop copy | Page table says free EU up to 30GB — confirm 5GB fair use at checkout | lebara.co.uk, 1 Sep |
Talkmobile 15GB neighbour | 47 European destinations | 5GB fair use | talkmobile.co.uk, 1 Sep |
A week in Spain can burn a 3GB roam cap while 5GB sits unused at home. If you actually holiday, the roam line matters more than 30p on the year.
PAC, eSIM, credit checks
Text PAC to 65075. Free, usually 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 cheap 5GB rolling SIM is a bad surprise if you still owe six months on a handset plan.
eSIM: SMARTY’s 5GB page flags SIM and eSIM. spusu’s 5 page flags eSIM. Confirm at checkout if you want the plan this afternoon rather than a 3-in-1 in the post. Lycamobile’s 5GB page is a physical SIM checkout this morning.
Credit checks: SMARTY, spusu, Lycamobile and Lebara all sell no-credit-check as a feature on the pages I opened. Many short rolling MVNO SIMs are lighter than a 24-month big-four contract, but I am not going to flatten every brand into “never checks”. If a checkout asks for a soft search, read the line before you blame the comparison table.
What I want you to do
Open Compare live SIM only deals on the SIM only hub. Filter around 5GB. If last month was under 4GB and you will lock 12 months on 1,000 UK minutes, Lebara 5GB at £4.50 (£54 year, lebara.co.uk, 1 September 2026) is the cash total to beat. If EE coverage works and you want unlimited UK calls, spusu 5 at £4.90 (£58.80 year) is the unlimited-calls total to beat. If you want Lycamobile’s international minutes on EE, the website-only £3.50 then £5 year is £58.50 until 30 September. If you want SMARTY’s own checkout on Three, £6 rolling is the direct price I verified this morning — and iD 20GB is the same pound until 8 September if 5GB is a guess rather than a measurement.
Do not buy a Talkmobile “5GB £4.95” tile from a comparison hub while talkmobile.co.uk sells 15GB at £5.95. Do not buy a Lebara “5GB £1.48” card while lebara.co.uk sells £5 / £4.50. Do not treat 5GB as the default cheap SIM when Ofcom’s average user needs 11.8GB.
If the phone has to change, compare phone deals instead. If you need 20GB, 100GB or unlimited, use those guides. This URL is 5GB, ranked by the year, retailer pages only.
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 5GB SIM only deal in the UK today?
The cheapest 12-month cash I can verify on a retailer page on Tuesday 1 September 2026 is Lebara 5GB at £4.50 a month on the 12-month toggle on lebara.co.uk — £54 for the year. That SKU is 1,000 UK minutes and texts, not unlimited. Rolling Lebara 5GB is £5 / £60. The cheapest unlimited-calls 5GB year is spusu 5 at £4.90 (£58.80) on spusu.co.uk. I am not headlining Talkmobile 5GB or the Lebara £1.48 uSwitch teaser.
Why did you drop Talkmobile and the Lebara £1.48 tile?
Because I could not buy them at the comparison price. Talkmobile’s own shop lists 15GB at £5.95 and 30GB at £6.95, not 5GB. Lebara’s £1.48-then-£4.95 5GB is a uSwitch exclusive — lebara.co.uk this morning is £5 rolling / £4.50 on 12 months, which is the row I ranked. A comparison exclusive that is not on the retailer is not a SwitchSquid ranking row.
Is Lycamobile really cheaper than spusu?
By 30p over twelve months, yes, if you take the website-only first month. It is not cheaper than Lebara’s 12-month shop price, and it is not cheaper as a product than spusu. Lyca’s 5GB plan is 1,000 UK calls and texts and 4G-first on their own page. spusu 5 is unlimited minutes and texts and uncapped 5G. Pick the one that matches how you actually use the phone.
Is 5GB enough if Ofcom says average use is 11.8GB?
For average users, no. Ofcom’s CMR 2026 figure is 11.8GB per mobile data user in 2025. 5GB is a light-user bucket: Wi-Fi at home and work, maps, messaging. If you already clear 5GB, move to the 20GB guide. If you blow past 80GB, read cheapest unlimited SIM only UK 2026.
Should I buy SMARTY 5GB or iD 20GB at £6?
If you truly use under 5GB and want SMARTY’s checkout, SMARTY 5GB at £6 is the Three 5GB row. If you are guessing, iD’s 20GB at the same £6 until 8 September 2026 is four times the data on the same network family. Reopen idmobile.co.uk before 8 September. The 20GB ranking is a different URL.
Does Talkmobile still do 5GB for £4.95?
Not on talkmobile.co.uk this morning. The shop’s cheapest rolling plan is 15GB at £5.95. Until the shop and the card agree on a 5GB SKU, I dropped it.
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.
Should I buy a phone on contract instead?
Only if you need the handset. Airtime at £4.90–£8 and a flagship at £45–£75 are not the same product. Compare phone deals for the handset total. Come back here for the 5GB SIM.
Sources
Lebara, fetched 1 September 2026: Best SIM only deals — 5GB, 1,000 UK minutes and texts, 100 international minutes; 30-day £5.00; 12-month £4.50; no £1.48/£4.95 on the shop. 12-month total £54.00 (avg £4.50). Rolling year £60.00.
spusu, fetched 1 September 2026: Plans and spusu 5 — 5GB, unlimited mins/texts, £4.90/mo rolling; EU/Switzerland roam 3GB / 500 mins / 500 SMS; uncapped 5G; eSIM. 12-month £58.80 (avg £4.90).
Lycamobile, fetched 1 September 2026: UK Plan Smart — 5GB, 1,000 UK calls and texts, 100 international minutes; £3.50 first month then £5.00; new customers, website only, 20 July–30 September 2026; EU roam 5GB cap. 12-month £58.50 (avg £4.88).
SMARTY, fetched 1 September 2026: 5GB plan and all plans — 5GB £6/mo rolling; unlimited UK calls/texts; eSIM; Three network; EU roam 12GB fair-use line on the 5GB page. 12-month £72.
giffgaff, research-verified 1 September 2026: £8 Golden Goodybag — 5GB £8/mo monthly rolling. 12-month £96.
Talkmobile, fetched 1 September 2026: SIM only deals — no 5GB SKU; 15GB £5.95 rolling; 30GB £6.95 rolling; roam 47 European destinations, 5GB fair use. uSwitch Talkmobile “5GB £4.95” treated as stale vs own shop.
iD Mobile, fetched 1 September 2026 via public plan copy on idmobile.co.uk: no 5GB SKU; PAYG 1GB £6 / 4GB £8 / 6GB £10; 20GB £6 promo 12 Aug–8 Sept 2026, new customers, is 20GB not 5GB.
VOXI, fetched 1 September 2026: SIM only plans — no 5GB; £10 plan is the cheap rung (60GB promo to 30 Sept then 20GB).
Ofcom Communications Market Report 2026: average monthly data per mobile data user 11.8GB in 2025 — CMR 2026 PDF.
SwitchSquid hubs, linked 1 September 2026: SIM only deals; 20GB SIM only deals UK; 100GB SIM only deals UK; cheapest unlimited SIM only UK 2026; phone deals.
Competitor note: uSwitch has no dedicated 5GB URL — 5GB is a filter on the 5G SIM / 30-day hubs; those pages still show Talkmobile 5GB (not on talkmobile.co.uk) and a Lebara £1.48 teaser (not on lebara.co.uk; shop is £5 / £4.50).
