Best unlimited data SIM 2023: The best SIM-only deals for bottomless browsing, streaming and gaming
Sick of running out of data? We’ve rounded up the best unlimited data SIM plans for serial streamers, social media butterflies and gamers
The best unlimited data SIM plans will give you peace of mind when you’re scrolling through the news on the train to work, sprinting along to Spotify on your run or finding the perfect restaurant on holiday. Slot one into your phone and you will never be caught short.
However, you shouldn’t simply buy the first unlimited data SIM you come across: there are lots of important factors to keep in mind, including the length of the contract, value for money, 5G compatibility and whether the price includes any extras.
To help, we’ve put together a handy buying guide that explains the basics, followed by a list of our favourite unlimited data SIM-only deals. Surf’s up!
How to choose the best unlimited data SIM for you
How much should you spend?
Prices for an unlimited SIM can vary wildly, depending on the length of the contract and additional features you’re getting. As a rule of thumb, though, we would hesitate to pay more than £30/mth for an all-you-can-use 5G SIM on a two-year plan. Anything under £20/mth might seem like a bargain, but you could be sacrificing speed or coverage so be sure to check the small print.
Third-party sites such as Affordable Mobiles and Mobiles.co.uk can offer eye-boggling savings on SIMs, although you will often have to claim back the money via cashback after a set period of time. If you don’t mind the bit of extra paperwork, go for it, but it’s always worth checking the network’s site beforehand to make sure you’re not missing out on goodies.
How long should the contract be?
You can normally pick between a one-month, 12-month or 24-month unlimited SIM contract. We would opt for a two-year plan because that’s how you can get the most browsing bang for your buck. The shorter contracts, meanwhile, will appeal to users who don’t want to be tied down for so long.
Does download speed matter?
Most mobile networks, with the notable exception of Vodafone, don’t specify a separate speed for their unlimited data SIM and include a flat rate across all of their plans. We’ve mentioned the most recent Opensignal 4G and 5G download speed results in the bite-size reviews below.
Is it worth getting a 5G-capable SIM?
5G has already been rolled out across dozens of towns in the UK, but huge swathes of the country still aren’t covered. Consequently, it’s worth checking if you’re able to get the fastest speeds before you make the buying decision – there’s no point paying for a service that you can’t access. That said, you will find that many of the best unlimited data SIMs are now 5G by default anyway.
Will I be able to use the SIM abroad?
Most of the leading mobile networks will offer some kind of scheme for using your SIM on your travels. Some opt for a daily data cap, while others let you use your entire allowance as usual. We’ve mentioned below if there’s a particularly holiday-friendly extra.
What extras should I look out for?
All unlimited data SIM plans come with endless minutes and texts as standard, but networks also try to stand out from the crowd by throwing in useful tools such as personal hotspots or treats like money off subscription services. We’ve mentioned any permanent extras below, but it’s worth perusing our list of the best time-limited SIM-only deals too.
READ NEXT: Best roaming SIM only deals
The best unlimited data SIMs you can buy in 2023
1. iD Mobile: The best budget unlimited data SIM
Price: £16/mth for 24 months | View offers at iD Mobile
iD Mobile’s unlimited offer is extraordinary, undercutting all of the competition at just £16/mth (was £18/mth) on a two-year deal. As you might expect, you’re not getting a cornucopia of features at such a low price, but the SIM is 5G-ready.
Even better, as iD Mobile piggybacks on Three’s network, you’re getting very respectable 4G download speeds: Three finished second in Opensignal’s latest 4G speed test behind the lightning-quick EE. Its 5G coverage is good too, with Three covering more of the UK than any other mobile network.
If you’re after a no-nonsense unlimited data SIM for a phenomenally low outlay, look no further than iD Mobile.
Read our full iD Mobile review
Key details – Contract length: 24 months; Price overall: £384; 5G: Yes; Unlimited texts and minutes: Yes; International roaming: Free in the EU; Optional extras: None
2. EE: The best unlimited data SIM for speed
Price: £36/mth for 24 months | View offers at EE
It’s the most expensive “vanilla” unlimited data SIM on this list by a country mile, but you’re getting the UK’s fastest 4G and 5G download speeds with EE.
In the Opensignal’s most recent round of tests, it was 21Mbits/sec faster than second-place O2 for 5G at 132Mbits/sec, while the gulf in class was even bigger for 4G: at 44Mbits/sec, it was 19Mbits/sec quicker than silver-medallist Three.
Its 5G coverage isn’t up there with Three or Vodafone, but the screamingly rapid speeds more than compensate for that. If you can afford it, EE’s unlimited data SIM is the gold standard. Bargain-seekers should look elsewhere, though.
Read our full EE review
Key details – Contract length: 12 months; Price overall: £396; 5G: Yes; Unlimited texts and minutes: Yes; International roaming: £2 per day in the EU; Optional extras: 6 months of Apple Music, Apple TV+, Apple Arcade
3. Three: The best-value unlimited data SIM
Price: £24/mth for 24 months | View offers at Three
Three was the perennial runner-up in Opensignal’s latest tests, finishing behind EE for 5G and 4G download speeds. However, it was streets ahead when it came to 5G coverage in the UK with 7.4%, a whole percentage point ahead of second-place Vodafone.
Useful extra features include a personal hotspot for sharing your bottomless data with devices such as a tablet or laptop and Three’s Go Roam Around the World, which lets you use your data in 71 countries for a daily fee (£2 in Europe and £5 elsewhere).
Even better, Three regularly chops 50% off the first six months of the plan, saving you a handy £69. It all adds up to an excellent-value package.
Read our full Three review
Key details – Contract length: 24 months; Price overall: £576; 5G: Yes; Unlimited texts and minutes: Yes; International roaming: £2 per day in the EU, £5 elsewhere; Optional extras: Three+ rewards app
4. Vodafone: The most versatile unlimited data SIM
Price: £26/mth to £41/mth for 24 months | View offers at Vodafone
Vodafone serves up a famous five unlimited data SIM plans, ranging from a 2Mbits/sec Unlimited Lite contract for £26/mth and 10Mbits/sec for £30/mth to an all-singing, all-dancing Unlimited Max + Entertainment package for a wallet-wilting £41/mth. You’re getting a lot with the latter, though: two years of YouTube Premium, Amazon Prime Video or Spotify.
Vodafone has the second-widest 5G coverage, but its speeds lag behind those of the other major networks, which is disappointing given the comparatively high price of its non-speed-limited plans. That said, most users will find an unlimited Vodafone plan that suits them – from news fanatics to content crunchers.
Read our full Vodafone review
Key details – Contract length: 24 months; Price overall: £624 to £984; 5G: Yes; Unlimited texts and minutes: Yes; International roaming: £2 per day in the EU, £6 elsewhere; Optional extras: 24 months of YouTube Premium, Amazon Prime Video or Spotify
5. O2: The best unlimited data SIM for extras
Price: £30/mth for 24 months | View offers at O2
O2 delivers the second-fastest 5G speeds after EE, according to Opensignal, but its 4G performance was the worst of the big four and its 5G coverage is nothing to write home about.
It’s all about the goodies here, though. The £30/mth cost on a two-year plan might initially seem steep, but you’re getting up to three months of free Apple Music and another three months free of another extra of your choice. Phew!
If that wasn’t enough, you can also get broadband savings if you’re a Virgin Media customer via the “Volt” scheme. If you’re someone who likes to get the most from their money, O2 is the SIM to pick.
Read our full O2 review
Key details – Contract length: 24 months; Price overall: £720; 5G: Yes; Unlimited texts and minutes: Yes; International roaming: Yes, via add-ons; Optional extras: 3 months of free Apple Music, plus 3 months of Disney+, Audible, McAfee Mobile Security Plus, Cafeyn, Amazon Music or Amazon Prime Video
6. Smarty: The best unlimited data SIM with a short plan
Price: £20/mth for one month | View offers at Smarty
Looking for a short-term, commitment-free contract? You will have to pay vast amounts for a one-month plan with the big providers. That’s where Smarty comes in: it piggybacks on Three’s network, which means excellent 4G and 5G speeds, and costs only £20 for a month of unlimited data.
You can cancel the contract at any time and it lets you roam as usual within the EU. Despite the lack of shiny extras, it’s an incredibly simple SIM-only plan that will leave you feeling like a smarty-pants.
Key details – Contract length: 1 month; Price overall: £20; 5G: Yes; Unlimited texts and minutes: Yes; International roaming: Yes; Optional extras: None
7. Lebara: The best unlimited data SIM for calling abroad
Price: £22.50/mth for 12 months | View offers at Lebara
Lebara is partnered with Vodafone in the UK, meaning you will be getting decent 5G coverage and so-so speeds, but it’s a brilliant choice for calling friends or family abroad.
If you sign up for the year-long £22,50/mth plan, you will get unlimited minutes when calling 41 countries around the world, including India, the US, China, Australia, New Zealand, Thailand, Malaysia, Canada, Hong Kong and South Korea. That’s staggering value compared to other SIMs on this list.
It doesn’t have the streaming extras of other options on this list, but it’s a phenomenal SIM for staying in touch, no matter where you are.
Key details – Contract length: 12 months; Price overall: £270; 5G: Yes; Unlimited texts and minutes: Yes, including unlimited minutes to 41 countries; International roaming: Free in the EU; Optional extras: None