If your mobile bill went up in April and you shrugged it off, you are not alone — and it is costing you real money. Ofcom confirmed that in-contract mobile price rises announced for 2026 landed between £1.80 and £2.50 a month. On a £10 tariff, £2.50 is a 25% increase. On a £36 tariff, the same £2.50 barely registers. The flat-cash system that replaced inflation-linked rises hits the cheapest plans hardest, which means the people least able to absorb it are absorbing the most.
The good news is that a SIM-only plan is the single easiest bill in your house to cut. There is no engineer visit, no installation window, no equipment to return. You keep your phone, you keep your number, and the whole switch takes about ten minutes. This guide compares the best SIM-only deals UK 2026 has to offer — the budget challengers, the big four networks, and the small print that decides whether your cheap deal stays cheap.
⚡ Quick Answer
For most UK users in 2026, iD Mobile offers the lowest headline prices (from around £6 a month) with data rollover and no CPI-linked mid-contract rises on SIM-only plans. VOXI is the better pick if you live in social and streaming apps, because that usage does not touch your data allowance. Choose giffgaff or SMARTY if you want no credit check and total flexibility. Only go direct to EE, O2, Vodafone or Three if you specifically need their coverage strength or bundled perks — you will pay more for the same masts.
Best SIM-Only Deals UK 2026: Full Comparison Table
Prices below reflect entry-level SIM-only tariffs available in July 2026. Allowances on budget networks change frequently, so treat the data figures as indicative and confirm at the point of sale.
| Network | Runs on | From (per month) | Contract options | Standout feature | Mid-contract rises? |
|---|---|---|---|---|---|
| iD Mobile | Three | Around £6 | 30-day, 12, 24 month | Data rollover + capped bills | No CPI/RPI rise on SIM-only |
| VOXI | Vodafone | £10 | 30-day rolling only | Unlimited social media data | No — rolling plan, cancel anytime |
| giffgaff | O2 | Around £6 | Rolling or 18 month | No credit check, Payback scheme | No rise guarantee on 18-month |
| SMARTY | Three | Low single figures | 30-day rolling | Data-only SIMs available | No — rolling plan |
| Tesco Mobile | O2 | Mid range | 30-day, 12 month | Clubcard perks, roaming pledge | Check tariff terms |
| EE | Own network | Premium | 12, 24 month | Widest rural coverage, Inclusive Extras | Yes — £2.50/month each April |
| O2 | Own network | Premium | 12, 24 month | O2 Priority rewards | Yes — £2.50/month from April 2026 |
| Three | Own network | Mid to premium | 12, 24 month | Fastest urban 5G speeds | Yes — check pounds-and-pence figure |
| Vodafone | Own network | Mid to premium | 12, 24 month | Strong overall coverage | Yes — check pounds-and-pence figure |
First, Understand What You Are Actually Buying
The UK has only four mobile networks that own physical infrastructure: EE, O2, Vodafone and Three. Every other brand you see advertised is a virtual operator renting capacity from one of those four. That single fact is the most valuable thing on this page, because it means you can often buy the exact same signal for half the price.
- Three’s network carries iD Mobile and SMARTY
- O2’s network carries giffgaff, Tesco Mobile and Sky Mobile
- Vodafone’s network carries VOXI and Talkmobile
- EE’s network carries BT Mobile and Plusnet Mobile
The practical consequence: if Three has poor indoor signal where you live, then iD Mobile and SMARTY will have poor indoor signal too. No amount of marketing changes that. Before you commit to any budget SIM, check the coverage map of its host network at your home postcode and your work postcode. Opensignal’s January 2026 UK report put EE ahead overall, with Three leading on urban 5G download speeds and O2 ranking highest for overall coverage reach.
iD Mobile: The Price Leader
Owned by Currys and running on Three’s masts, iD Mobile has been quietly winning the price war for years. Ofcom’s own pricing research found that iD Mobile offered the cheapest pay-monthly SIM-only tariffs across the 10GB to 100GB data range for a sustained multi-year stretch. That is not a marketing claim — it is a regulator’s finding.
Entry plans start around £6 a month, and the mid-tier deals are where it gets genuinely aggressive: three-figure data allowances routinely appear under £10. The two features that matter most day to day are data rollover, which pushes unused allowance into next month, and capped contracts, which stop you accidentally running up a bill you cannot pay. For anyone managing a household budget, that cap is worth more than an extra 20GB.
✔ Pros
- Consistently the lowest price per GB in the UK market
- Data rollover on all SIM-only plans
- Capped contracts prevent bill shock
- SIM-only plans exempt from annual CPI/RPI increases
- Free EU and worldwide roaming across 50 destinations
✘ Cons
- Credit check required on all plans — you can be declined
- Inherits Three’s weaker rural and indoor coverage
- Some headline deals are 12 or 24 month, not rolling
- Customer service is online-first
Check iD Mobile SIM-Only Deals →
VOXI: Best for Social and Streaming Heavy Users
VOXI is Vodafone’s own budget brand, and it solves a specific problem better than anyone else. Every VOXI plan includes unlimited data for selected social and messaging apps — WhatsApp, Instagram, Snapchat, Facebook, Messenger, Pinterest and others — which does not count against your allowance at all. On higher tiers, that extends to unlimited video streaming on services such as Netflix, Prime Video and YouTube.
If you are the kind of person who burns 40GB a month on scrolling and streaming, a £10 VOXI plan can genuinely outperform a £20 plan elsewhere, because the bulk of your usage is free. If you mostly browse, navigate and email, the maths flips and iD Mobile wins. Be honest about your own usage before choosing — check your phone’s own data breakdown for the last three months.
Two live offers are worth knowing about as of July 2026: VOXI is running a triple-data promotion on selected plans until 30 September 2026, which pushed the £10 tier from 20GB to 60GB, and a Double Rewards period on its VOXI Drop loyalty programme running through to early October. Everything is 30-day rolling, so there is no lock-in and no mid-contract rise to worry about.
✔ Pros
- Unlimited social media data on every single plan
- Unlimited video streaming on higher tiers
- Vodafone coverage and 5G at budget prices
- 30-day rolling only — change, pause or cancel anytime
- No credit check, and the old age restriction has been removed
✘ Cons
- Entry price of £10 is higher than iD Mobile or giffgaff
- Small range of plans — limited choice
- No genuinely light-user option
- No 12-month contracts, so no long-term discount
- Poor value if your usage is browsing rather than apps
giffgaff and SMARTY: The No-Credit-Check Options
Both of these deserve a place in any honest comparison, even though neither is a partner of ours. giffgaff runs on O2 and starts around £6 a month, with 5G included at no extra cost on every plan. Its distinguishing features are the absence of a credit check, the community-forum support model, and the Payback scheme that rewards members for helping other members. Unlimited data has recently been available from around £14 a month, though that figure sits on an 18-month term rather than giffgaff’s usual rolling plan — read the term length carefully before assuming it is flexible.
SMARTY runs on Three and takes a deliberately stripped-back approach: a handful of plans, no perks, low prices. It is one of the few networks offering data-only SIMs, which makes it a strong choice for a tablet, a mobile hotspot or a dashcam. If you want the cheapest possible way to get data into a second device, start here.
The Big Four: When Paying More Is Justified
Going direct to EE, O2, Vodafone or Three costs more for identical signal. There are three situations where it is still the right call.
Rural coverage. EE has the widest geographic footprint in the UK. If you live somewhere the budget brands struggle, EE direct may be the only plan that actually works — and a cheap SIM with no signal is not a saving.
Bundled subscriptions. EE’s higher tiers include Inclusive Extras such as Apple Music or Netflix. O2’s plans have offered Disney+, Amazon Prime or Audible periods. If you already pay for one of those separately, the bundle can close the price gap. Do the arithmetic rather than assuming.
Rewards schemes. O2 Priority is genuinely useful if you regularly buy event tickets or use high-street offers. Three+ works similarly. These have real cash value for some households and none at all for others.
The Small Print That Decides Everything: Mid-Contract Price Rises
This is the section most SIM comparison pages skip, and it is the section that determines what you actually pay over a year.
Since 17 January 2025, Ofcom has banned providers from tying mid-contract increases to inflation. Any rise written into a new contract must be stated in pounds and pence, clearly, before you sign. In principle that is a win for transparency. In practice it has produced an uncomfortable side effect: because the increase is now a flat cash sum rather than a percentage, it lands proportionally hardest on the cheapest tariffs. A £2.50 rise on a £10 SIM is 25%. The same £2.50 on a £40 SIM is roughly 6%.
Where the networks stand in 2026:
- EE applies a £2.50 monthly increase each April to SIM-only plans taken out from July 2025 onwards. Plans taken between April 2024 and July 2025 rise by £1.50. Older legacy plans still run on CPI plus 3.9%, which produced a 7.3% increase in April 2026 based on the December 2025 CPI figure of 3.4%.
- O2 increased bills by £2.50 from April 2026, higher than the £1.80 figure it had originally signalled. The move drew public criticism from consumer campaigners and prompted the Government to write to Ofcom asking for a review.
- iD Mobile states that its SIM-only plans are not subject to annual CPI or RPI increases.
- giffgaff guarantees no mid-contract price rises on its 18-month plans.
- Rolling 30-day plans from VOXI, SMARTY and giffgaff sidestep the issue entirely — if the price changes, you leave.
One further protection worth knowing: if your provider failed to set out the increase clearly before you signed, you are entitled to 30 days’ notice and a penalty-free exit. It is worth checking your original contract paperwork if a rise took you by surprise.
If Money Is Tight: Social Tariffs
If your household receives Universal Credit, PIP or similar support, you may qualify for a social tariff. These start at roughly £12.50 a month, there are more than thirty available across providers, and they are generally exempt from annual price rises. The uptake problem is awareness rather than eligibility — around 70% of eligible households do not know these tariffs exist. If that might be you, ask your provider directly; they are not always advertised prominently.
How to Switch and Keep Your Number in Under 10 Minutes
- Check your exit position. If you are still inside a minimum term, confirm any early termination fee before doing anything else.
- Check host-network coverage at home and at work using the coverage map of the network your new SIM actually runs on.
- Text PAC to 65075 from your current SIM. Your existing provider must send you a Porting Authorisation Code, free of charge, usually within minutes.
- Order the new SIM and give the PAC code during sign-up.
- Wait one working day. Your number transfers automatically and the old plan closes itself. You do not need to phone anyone to cancel.
A PAC code is valid for 30 days, so requesting one does not commit you to anything. If you would rather not keep your number, text STAC to 75075 instead.
Best SIM-Only Deals UK 2026: Verdict
For the majority of UK households, iD Mobile is the value winner. The prices are the lowest in the market on a per-gigabyte basis, data rollover reduces waste, capped contracts protect you from surprise bills, and the exemption from annual CPI increases on SIM-only plans means the price you agree is the price you keep paying. The trade-off is Three’s coverage, so check your postcode first.
VOXI wins decisively for one specific user: the heavy social and streaming user. If most of your screen time sits inside apps that VOXI zero-rates, you are effectively buying unlimited data for £10 a month on Vodafone’s network. That is difficult to beat, and the rolling contract means no price-rise exposure at all.
Choose giffgaff or SMARTY if a credit check is a barrier or you want maximum flexibility. Go direct to EE only if rural coverage genuinely requires it. And whatever you pick, set a calendar reminder for one month before your term ends — the single biggest cause of overpaying in the UK mobile market is simply forgetting to switch.
Doing all this on an older handset? A SIM-only plan pairs perfectly with a refurbished or mid-range phone, and the combined saving over two years is usually several hundred pounds compared with a bundled contract.
Frequently Asked Questions
What is the cheapest SIM-only deal in the UK right now?
Entry-level SIM-only plans currently start at around £6 a month from iD Mobile and giffgaff, with some smaller providers advertising even lower rates for very small data allowances. The cheapest plan is rarely the best value, though — compare the price per gigabyte and check whether the deal is rolling or fixed-term.
Do budget networks have worse coverage than EE, O2, Vodafone or Three?
No. Virtual operators use the same masts as their host network, so coverage and speeds are identical to that network in your area. iD Mobile and SMARTY match Three, giffgaff and Tesco Mobile match O2, and VOXI matches Vodafone. What you lose is extras such as rewards schemes and bundled subscriptions, not signal.
Can my SIM-only price go up mid-contract in 2026?
Yes, on fixed-term contracts with most major networks. Since January 2025 any increase must be shown in pounds and pence before you sign rather than linked to inflation. EE and O2 both applied £2.50 monthly increases in April 2026. iD Mobile states its SIM-only plans are not subject to CPI or RPI rises, and 30-day rolling plans avoid the issue completely.
Do I need a credit check for a SIM-only plan?
It depends on the provider. iD Mobile, O2, Three, Vodafone, Sky Mobile and Tesco Mobile run credit checks, particularly on 12 and 24 month terms. giffgaff, SMARTY, VOXI and most prepay-style networks do not, which makes a rolling plan from one of them the fastest route to a working SIM.
Is 5G included on cheap SIM-only plans?
Usually, but not always. Most networks now include 5G at no extra cost, though some of the very cheapest tiers still default to 4G only. You also need a 5G-capable handset and 5G coverage at your location for it to make any difference. Confirm 5G is included on the specific plan before paying extra for it.
How long does it take to switch and keep my number?
Text PAC to 65075 from your current SIM, give the code to your new provider during sign-up, and the transfer typically completes within one working day. Your old plan closes automatically — you do not need to call to cancel.
Should I choose a 30-day rolling plan or a 12-month contract?
Rolling plans give you the freedom to move whenever a better deal appears and protect you from mid-contract increases. Fixed 12-month terms usually carry a lower monthly price but may include an annual rise. If you enjoy shopping around, roll. If you want to set it and forget it, a fixed term with a stated pounds-and-pence rise can still work out cheaper overall.
Can I use a SIM-only plan abroad?
Many UK networks include roaming allowances in the EU and beyond. iD Mobile includes free roaming across 50 destinations with a data cap, and Tesco Mobile has committed to no EU roaming fees. Always check the fair use data limit, because exceeding it abroad is where unexpected charges appear.
Pair Your New SIM With the Right Handset
A SIM-only plan only saves you money if you already own a phone you are happy with. If yours is on the way out, buying a handset outright and pairing it with a cheap SIM almost always beats a bundled contract over two years.
Browse SIM-Free Smartphones on Amazon UK →
Prices and offers verified July 2026. Mobile tariffs change frequently — always confirm current pricing and terms on the provider’s own site before purchasing. MegaStore76 may earn a commission from links on this page at no extra cost to you.
