Last updated: Wednesday 21 October 2026 (Europe/London).
Next update: weekly, and whenever Lebara, Mozillion, Chattr or 1pMobile change a price or an October offer.
By: Switch Editorial Team, Switch Squid Ltd
As of 21 October 2026, the best-value SIM only deal we found is Lebara’s 30GB plan at £8 every 30 days on the plan our link opens, with no contract and no credit check. Mozillion’s 30GB rolling plan is £9 a month if you want no price rises and the option to leave each month, and Chattr’s unlimited plan drops to £3.75 for month one with code OCT75 this October. The catch with the cheapest offers is the small print: introductory discounts last one month, and roaming and data caps differ by network.
This SwitchSquid guide puts the price first. You get five picks at the top, a full comparison table with codes, and separate sections for cheap SIMs and refurbished phones, so you can choose in a couple of minutes rather than an evening.
New this week: Mozillion 120GB a month for 24 months is £132 paid once, which works out at £5.50 a month, with no credit check and no mid-contract price rises. Mozillion says this runs to midnight on Sunday 25 October. See the 120GB Mozillion deal
We may earn a commission if you buy through links on this page. It doesn’t change the price you pay.
Top picks this month
Cheapest 30GB: Lebara 30GB, £8 every 30 days, no contract.
Most flexible 30GB: Mozillion 30GB, £9 a month on a 1-month plan (£8 a month on 24 months).
Cheapest unlimited month one: Chattr Freedom One, £3.75 for month one with Code: OCT75, then £15.
Cheapest 50GB: 1pMobile 50GB, £10 every 30 days.
Phone upgrade: £5 off any new or refurbished phone at Mozillion with Code: TREAT5.
Lebara 30GB — £8 every 30 days
30GB of 4G and 5G data with unlimited UK minutes and texts, plus 100 international minutes, for £8 every 30 days on the plan this link opens (checked 21 October 2026)
30-day rolling, no credit check and no yearly price rises, on Vodafone’s network
Main limitation: it renews every 30 days rather than each calendar month, so you pay 13 times a year, not 12
Which SIM only deal is best this month?
For most people who use between 10GB and 30GB a month, Lebara’s £8 30GB plan is the best value we found on 21 October 2026. It undercuts Lebara’s own standard 30GB price of £10 on its main SIM page, and it carries the things that matter on a cheap SIM: no contract, no credit check, 5G at no extra cost and no annual price rise.
If you would rather stay on a calendar-month plan and want the freedom to change your allowance or leave, Mozillion’s 30GB plan is £9 a month on a 1-month term. Commit to 12 months and it is £8.50, or 24 months for £8. Mozillion says its plans have no mid-contract price rises and no credit check for SIM only.
Heavy users are better served by Chattr. Its Freedom One plan gives unlimited 5G data, calls and texts on O2’s network for £15 a month, and the price falls the longer you stay: £14 from month six and £13 from month twelve. With the October code OCT75, month one costs £3.75.
Cheap SIM only deals compared
Prices are from each network’s own website on 21 October 2026. “Year one” is our estimate of what you would pay over the first 12 months if nothing changes, including any first-month discount.
Brand | Offer | Data | Contract | Code | Upfront | Best for |
|---|---|---|---|---|---|---|
Lebara | £8 every 30 days (about £104 a year, 13 renewals) | 30GB | 30-day rolling | No code needed | £0 beyond the first payment | Low cost, calling abroad, Vodafone coverage |
Mozillion | £9 a month rolling (£108 a year); £8.50 on 12 months; £8 on 24 months | 30GB | 1, 12 or 24 months | No code needed | £0 beyond the first payment | No price rises, flexibility |
Chattr | £3.75 month one, then £15, £14 from month six, £13 from month twelve (about £161 in year one) | Unlimited | No contract, monthly | Code: OCT75 (October, month one only) | £0 beyond the first payment | Heavy data users on O2 |
1pMobile | £10 every 30 days (about £130 a year, 13 renewals) | 50GB | 30-day rolling | No code needed | £0 beyond the first payment | Mid users who want 50GB and EU roaming |
Mozillion phones | £5 off any new or refurbished phone, SIM-free or on a monthly plan | Depends on plan | SIM-free or 24 months | Code: TREAT5 | Phones from £450 SIM-free (Galaxy S25 FE and S25 when we checked) | Upgrading the handset as well as the SIM |
Mozillion 30GB — £9 a month, leave any month
30GB with unlimited calls and texts and EU roaming for £9 a month on a 1-month plan (checked 21 October 2026)
Total over a year at that price: £108. The same 30GB is £8.50 a month on 12 months or £8 a month on 24 months
Main limitation: EU roaming on the 30GB plan has a 7.5GB fair-use allowance
Best cheap SIM for light and mid users
If you mostly use your phone on Wi-Fi and want a low bill, the 30GB tier is the sweet spot this month. Paying extra for unlimited only makes sense if you stream on mobile data, hotspot a laptop or rarely sit on Wi-Fi.
Lebara is the cheapest 30GB we found. Its plans include international minutes to more than 50 countries, which makes it a strong pick if you call family abroad. You can use your allowance in the EU and India at no extra cost. The thing to watch is the 30-day cycle: it renews 13 times a year, so the true annual cost of £8 a period is about £104, still well under most rivals.
Mozillion costs a little more on a monthly plan but suits anyone who likes a calendar-month bill and wants to lock in a price. Its 24-month 30GB plan at £8 a month works out at £96 a year with no mid-contract price rises, which is the same as Lebara over 12 renewals and avoids the 13th payment.
1pMobile is worth a look if 30GB feels tight. Its 50GB plan is £10 every 30 days with unlimited UK calls and texts, 5G and roaming in 46 European destinations. The 100GB plan is £15.
Best SIM only deal for heavy data users
Chattr’s Freedom One is the stand-out unlimited offer this month. At £15 it is already competitive, and the October code OCT75 takes 75% off the first month, bringing it to £3.75. After that you pay £15 for months two to five, £14 for months six to eleven, and £13 from month twelve. There is no contract and no credit check, and Chattr runs on O2’s network, which also brings O2 Priority perks.
Two points to check before you order. The code applies to month one only, so budget for £15 from month two. And because Chattr has no contract, the discount is a one-off rather than a reason to stay; the falling price is what rewards loyalty.
To use the code, choose Freedom One on Chattr’s website and enter OCT75 in the promo code box at checkout before you pay. Chattr describes it as an October offer for month one.
Refurbished phones: where the October code helps
If your handset is the reason you are tied to an expensive contract, buying a refurbished phone outright and pairing it with a cheap SIM is often the lowest total cost over two years. Mozillion sells new and refurbished phones, and it is offering £5 off any new or refurbished phone with Code: TREAT5, either SIM-free or on a monthly plan. When we checked on 21 October 2026, its phone listings started at £450 SIM-free for the Samsung Galaxy S25 FE and Galaxy S25, and you can filter the range by condition, including refurbished grades.
A £5 saving is small on a £450 phone, so treat it as a bonus rather than the deciding factor. The bigger saving comes from the combination: a SIM-free phone plus a £8 to £9 30GB SIM usually beats a 24-month handset contract once you add up the total cost. Our guide to whether refurbished phones are any good covers grades, batteries and warranties.
Planning a trip? Travel eSIMs are covered in our separate best travel eSIM deals guide, so this page sticks to UK SIM plans.
How to switch and keep your number
Check your current contract end date. If you are still in a minimum term, your network may charge an early exit fee.
Text PAC to 65075 from your current phone. You get a free PAC code by text, valid for 30 days.
Order your new SIM or eSIM and enter the PAC when asked, or add it in your new network’s app once the SIM arrives.
Your number moves within one working day, and your old contract is cancelled automatically.
Not sure which allowance you need? Squid AI can suggest a plan from a short description of how you use your phone, and our cheap SIM only deals page lists more options.
What to check before you buy
Billing cycle. 30-day plans renew 13 times a year. Monthly plans renew 12 times.
Introductory codes. Discounts such as OCT75 cover month one only. Budget for the full price afterwards.
Roaming. EU roaming caps vary. Mozillion’s 30GB plan allows 7.5GB in the EU, while Lebara covers the EU and India.
Network coverage. Lebara uses Vodafone and Chattr uses O2. Check coverage at your postcode before switching.
Price rises. Lebara and Mozillion both say there are no annual or mid-contract price rises on these plans.
Frequently asked questions
What is the cheapest 30GB SIM only deal right now?
On 21 October 2026, the cheapest 30GB plan we found was Lebara at £8 every 30 days on the plan our link opens, with unlimited UK minutes and texts. Mozillion’s 30GB plan is £9 a month on a 1-month term, or £8 a month on 24 months.
How do I use Chattr code OCT75?
Choose Chattr’s Freedom One plan, then enter OCT75 in the promo code box at checkout before paying. It takes 75% off month one, so the first month costs £3.75, and Chattr describes it as an October offer. From month two you pay £15.
Is a 30-day SIM the same as a monthly SIM?
Not quite. A 30-day plan renews every 30 days, which means 13 payments a year instead of 12. Lebara’s £8 plan therefore costs about £104 over a full year, while Mozillion’s monthly 30GB plan costs £108 on the 1-month term.
Do these SIM only deals need a credit check?
Lebara, Chattr and Mozillion’s SIM only plans are sold without a credit check, according to each network’s website on 21 October 2026. Phones bought on monthly finance are different and may involve a credit check.
Can I keep my number when I switch?
Yes. Text PAC to 65075 from your current phone to get a free PAC code, then give it to your new network when you order or activate the SIM. Your number usually moves within one working day.
Is unlimited data worth it?
Only if you stream on mobile data, use your phone as a hotspot or rarely connect to Wi-Fi. If you are mostly on Wi-Fi at home and work, a £8 to £10 plan with 30GB to 50GB is usually enough. Chattr’s unlimited plan at £15 is good value if you do need it.
Can I get money off a refurbished phone this month?
Mozillion is offering £5 off any new or refurbished phone with code TREAT5, SIM-free or on a monthly plan. Its phone listings started at £450 SIM-free for Samsung Galaxy S25 models when we checked on 21 October 2026.
Our verdict
For a low bill with no contract, Lebara’s 30GB plan at £8 every 30 days is the one to beat this month. Pick Mozillion at £9 a month if you want a calendar-month plan you can leave any time, Chattr with code OCT75 if you need unlimited data, and Mozillion’s phones with code TREAT5 if the handset needs replacing too.
Mozillion new and refurbished phones — £5 off with code TREAT5
£5 off any new or refurbished phone, SIM-free or on a monthly plan, as an October offer from Mozillion
Phones from £450 SIM-free (Samsung Galaxy S25 FE and S25 when we checked on 21 October 2026), with refurbished grades alongside new
Main limitation: £5 is a small saving on a phone, so compare the total cost with a cheap SIM before you buy
Check availability Code: TREAT5
