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SIM only deals are the cheapest way to run a phone in the UK. You keep the handset you own, pay only for minutes, texts and data, and skip the 24-month handset contract.
The market has changed a lot since our last guide. Vodafone and Three have merged. New players like Revolut and AO have launched. And while the big networks keep adding a fixed price rise every April, most smaller providers now promise no mid-contract rises at all.
This guide compares the big four networks and 15+ smaller providers (MVNOs) so you can find the best SIM only deal for how you actually use your phone.
Prices checked 21 to 22 October 2026, from each provider's website or from MoneySuperMarket, Uswitch and Confused where a provider's own page wouldn't load. Deals change weekly, so always confirm the price before you buy.
Best SIM only deals at a glance
| Best for | Pick | Why |
|---|---|---|
| Cheapest unlimited data | Lycamobile | Unlimited for £12.50 a month, 30-day rolling |
| Best all-round value | SMARTY | 100GB for £10, unlimited for £17, no annual price rises, refunds unused data |
| Cheap data on a budget | Lebara | 50GB for £7.95, intro offer for the first three months |
| Free EU roaming | O2 | Up to 25GB in the EU included. The only big network that doesn't charge |
| Best coverage and speed | EE | Top of RootMetrics H1 2026 and winner of 11 Opensignal awards |
| Heavy social media users | VOXI | Social apps don't use your data on any plan |
| Tesco shoppers | Tesco Mobile | Clubcard Prices frozen for the whole contract |
What's changed since 2024
- Vodafone and Three are now one company. VodafoneThree launched in mid-2025. Both brands still exist, along with SMARTY, VOXI and Talkmobile. Customers on Vodafone and Three now roam onto each other's masts automatically, which has improved coverage, especially for Three and SMARTY users.
- Annual price rises are fixed in pounds. Ofcom banned inflation-linked rises, so the big networks now add a set amount each April, usually £2.50 a month. Check what your contract will cost in year two, not just month one.
- Most MVNOs now freeze prices. SMARTY, iD Mobile, Lebara, Lycamobile, VOXI and giffgaff (on 18-month plans) all advertise no annual rises.
- New providers. Revolut Mobile and AO Mobile have both launched on Vodafone's network. BT Mobile is back, but only for BT Broadband customers.
- EU roaming costs more. O2 is now the only big network that still includes EU roaming as standard.
The big four networks
1. EE SIM only deals
Network: its own (owned by BT)
EE is still the UK's best network on the independent tests. It scored 95.6 in RootMetrics' H1 2026 study, first or joint first in every category, and took 11 awards in Opensignal's January 2026 report, including reliability and download speed.
- 200GB, 1-month: £27
- Unlimited, 1-month: £31.50
Prices via Uswitch. EE's own plan list didn't load when we checked.
Price rises: +£2.50 a month every 31 March.
Extras: Inclusive Extras like Netflix, Apple One and TNT Sports on some plans. EU roaming is a paid add-on on most plans.
Choose EE if coverage and speed matter more than price. Look elsewhere if you're on a tight budget or travel in Europe a lot.
2. O2 SIM only deals
Network: its own (Virgin Media O2)
O2 won Opensignal's overall Coverage Experience award. Its standout feature is roaming: up to 25GB of EU data is included on every plan.
- Classic 40GB, 24 months: £19.50
- Classic 100GB, 24 months: £21.50
- Plus Unlimited, 24 months: £25.49
Price rises: +£2.50 a month each April.
Extras: Priority rewards. Plus and Ultimate plans add roaming in the US, Canada and Australia.
Choose O2 if you travel in Europe. Look elsewhere if you want the cheapest price. O2 came last in RootMetrics' H1 2026 scores.
3. Vodafone SIM only deals
Network: VodafoneThree
Vodafone customers now get Three's masts too, which has filled in coverage gaps. It didn't win any Opensignal awards in the latest report but came third in RootMetrics with 88.4.
- 50GB Red, 24 months: £21
- 100GB, 24 months: £24
- Unlimited Plus, 24 months: £26 (includes 25GB roaming in 52 European destinations)
Price rises: +£2.50 a month each April (£1.50 on Basics plans).
Extras: discounted extra lines with Together. EU roaming only included on Plus and Premier plans. Otherwise a roaming pass costs extra.
Choose Vodafone if you want an unlimited plan with EU roaming built in. Look elsewhere if you just need data at the lowest price.
4. Three SIM only deals
Network: VodafoneThree
Three is now the cheapest of the big four by a distance. It also won Opensignal's 5G download speed award at 187Mbps, and came second in RootMetrics.
- 60GB, 12 months: £8
- 100GB, 12 months: £10
- 120GB, 12 months: £12
Prices via MoneySuperMarket. These rise by roughly £2 a month from April 2027.
Extras: Three+ rewards. Go Roam in the EU costs £2.75 a day for new customers, with a 12GB cap.
Choose Three if you want big-network backing at MVNO prices. Look elsewhere if you roam in Europe often.
Best MVNO SIM only deals
MVNOs (mobile virtual network operators) rent space on the big four networks. You get the same masts and coverage, usually for much less, often with no contract and no annual price rises.
| Provider | Network | Example plans (per month) | Annual rises? | Standout perk |
|---|---|---|---|---|
| SMARTY | Three | 18GB £6, 100GB £10, Unlimited £17 (30-day) | No | Refunds £1 per unused GB |
| Lebara | Vodafone | 50GB £7.95 (intro £3.18 for 3 months) | No | EU and India roaming |
| Lycamobile | EE | 30GB £5, 120GB £10, Unlimited £12.50 (30-day) | No | Cheapest unlimited, 100 international minutes |
| iD Mobile | Three | 100GB £12, Unlimited £20 (1-month). 24m Unlimited £17 | No | Data rollover, bill capping |
| giffgaff | O2 | Rolling: 20GB £10, Unlimited £35. 18m: 100GB £15, Unlimited £25 | No (18m plans) | No credit check, 5GB EU |
| VOXI | Vodafone | 20GB £10, 300GB £20 (promo), Unlimited £35 (30-day) | No | Endless social media on every plan |
| Talkmobile | Vodafone + Three | 30GB £6.95, 100GB £9.95 (30-day) | Not stated | Uses both networks |
| Tesco Mobile | O2 | 6GB £6 (12m), 12GB £9 (24m), 50GB £10 (1-month) | Clubcard Prices frozen | Clubcard points, EU roaming |
| Sky Mobile | O2 | 24m: 25GB £10 then £14, Unlimited £21 then £25 | May rise | Piggybank data rollover |
| Honest Mobile | Three | Unlimited £25 (£12.50 for first 2 months) | No | Bills drop up to 30% the longer you stay |
| Revolut Mobile | Vodafone | Unlimited from £14.99 | Not stated | 20GB roaming in EU and US |
| AO Mobile | Vodafone | 500GB £18, or £12 for AO members | Not in year one | One simple plan |
| Utility Warehouse | EE | 10GB £6, Unlimited £13 (rolling) | Not stated | Discounts when bundled with energy |
| 1pMobile | EE | 50GB £10, Unlimited £25 (30-day) | Not stated | 1p per minute, text or MB on PAYG |
| Asda Mobile | Vodafone | 10GB £5.95, 50GB £7.95, 100GB £12 (12m/24m) | Not stated | Low entry price |
| CMLink | EE | 20GB £9, Unlimited £30 (1-month) | Not stated | China and Hong Kong roaming |
SMARTY
Our top pick for most people. SMARTY runs on Three, which now shares Vodafone's masts, so coverage has improved. Plans are 30-day rolling, there are no annual rises, and it refunds you for data you don't use. Unlimited for £17 is hard to beat from a provider this established. Get a SMARTY SIM with Reboxed.
Lebara
Lebara is built for cheap data and international use. 50GB for £7.95 on Vodafone's network is strong value, and roaming covers the EU and India. A good fit if you have family abroad.
Lycamobile
The cheapest unlimited plan we found at £12.50 a month, with no contract and no annual rise. It also includes 100 international minutes. Customer service reviews are mixed, so it's best if you rarely need support.
iD Mobile
Owned by Currys and running on Three. iD has no annual price rises, rolls over unused data and lets you cap your bill. The 24-month unlimited plan at £17 is a good long-term option.
giffgaff
Runs on O2. Rolling plans are pricier than rivals, but the 18-month deals are good value and come with no mid-contract rises. No credit check, which helps if you've struggled to get a contract elsewhere.
VOXI
Vodafone's youth-focused brand. Every plan includes endless social media, so TikTok, Instagram and Snapchat don't touch your allowance. Price-locked and 30-day rolling.
Tesco Mobile
Runs on O2. If you shop at Tesco, Clubcard Prices are frozen for the whole contract and you earn points on your bill. Also includes roaming in 48 destinations.
Sky Mobile
Best for Sky TV customers. Unused data goes into a Piggybank you can use later or share with the family. Watch the intro pricing: most plans step up after 12 months.
Revolut Mobile and AO Mobile
Two newcomers on Vodafone's network. Revolut bundles roaming in the EU and US into a cheap unlimited plan for app users. AO keeps it simple with one 500GB plan and no price rise in the first year.
Talkmobile, Utility Warehouse, 1pMobile, Asda Mobile and CMLink
Talkmobile is a cheap way onto both the Vodafone and Three networks. Utility Warehouse makes sense if you already take its energy or broadband. 1pMobile suits very light users on pay as you go. Asda Mobile has some of the lowest entry prices around. CMLink is a niche pick for people who travel to China and Hong Kong.
Which network has the best coverage?
All MVNOs use one of the big four networks, so check coverage for the host network, not the brand.
| Network | RootMetrics H1 2026 | Opensignal (Jan 2026) | MVNOs using it |
|---|---|---|---|
| EE | 95.6 (1st) | 11 awards incl. reliability and speed | Lycamobile, Utility Warehouse, 1pMobile, CMLink |
| Three | 89.5 (2nd) | 5G download and upload speed | SMARTY, iD Mobile, Honest Mobile |
| Vodafone | 88.4 (3rd) | No awards | Lebara, VOXI, Talkmobile, Asda, Revolut, AO |
| O2 | 84.1 (4th) | Overall coverage experience | giffgaff, Tesco Mobile, Sky Mobile |
RootMetrics tests in 16 cities, so rural results can differ. Always check the host network's coverage checker for your postcode before switching.
How to choose: MVNO or big network?
Go with an MVNO if:
- You want to save money. Unlimited data from £12.50 to £17 versus £25+ on the big networks.
- You hate contracts. Most MVNOs offer 30-day rolling plans.
- You want a fixed price. Most MVNOs don't add annual rises.
Stick with a big network if:
- You want perks. Streaming bundles, rewards apps and extras.
- You travel. O2's included EU roaming can save more than a cheaper plan.
- You need the fastest speeds at busy times. Networks can prioritise their own customers when masts are congested.
Our pick for most people: SMARTY for value, Lycamobile for the cheapest unlimited, and O2 if you travel in Europe.
Pair your SIM with a refurbished phone
A SIM only deal plus a refurbished phone is the cheapest way to get a great phone. You own the handset outright, there's no 24-month lock-in, and you avoid the markup built into handset contracts.
- Refurbished iPhone 17 Pro Max
- Refurbished iPhone 16
- Refurbished Samsung Galaxy S25
- Refurbished Google Pixel 9
Every Reboxed® phone passes our 70-point TechCheck® and comes with at least 80% battery health. Got an old phone in a drawer? Trade it in to cut the cost further.
FAQs
What is a SIM only deal?
A plan that gives you a SIM card with minutes, texts and data, but no phone. You use a handset you already own, so it's much cheaper than a phone contract.
What's the cheapest unlimited SIM only deal in the UK?
When we checked in October 2026, Lycamobile had unlimited data for £12.50 a month on a 30-day plan. AO Mobile (for members), Revolut Mobile and SMARTY are close behind.
Do SIM only deals go up every year?
On the big four, yes. EE, O2, Vodafone and Three add a fixed amount each spring, usually £2.50 a month. Most MVNOs, including SMARTY, iD Mobile, Lebara and Lycamobile, don't.
Will my phone work with any SIM only deal?
Yes, as long as it's unlocked. If you're not sure, try a SIM from another network or ask your current provider.
Can I keep my number when I switch?
Yes. Text "PAC" to 65075 to get your code, then give it to your new provider. Your number moves in one working day.
Which network includes free EU roaming?
O2 is the only big network that includes it on every plan, up to 25GB. Many MVNOs, including SMARTY, Lebara, iD Mobile and Tesco Mobile, include it too.
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