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 list of our favourite unlimited data SIM-only deals based on our roundup of the best mobile networks, followed by a handy buying guide that answers the most important questions. Surf’s up!
The best unlimited data SIMs you can buy in 2024
1. EE: The best unlimited data SIM for speed
Price: £33/mth (free for first 3 months) | Data: Unlimited | Plan: 24 months
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
The monthly price shown will increase on 31 March 2024 by the Consumer Price Index rate of inflation plus 3.9%.
2. Smarty: The best unlimited data SIM on a budget
Price: £16/mth, was £20/mth | Data: Unlimited | Plan: 1 month
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 £16 for a month of unlimited data.
You can cancel the contract at any time and it lets you roam as usual within the EU (up to 12GB). Despite the lack of shiny extras, it’s an incredibly simple SIM-only plan that will leave you feeling like a smarty-pants.
Read our full Smarty review
3. iD Mobile: The best longer-term unlimited data SIM plan
Price: £8/mth for 6 months, then £16/mth | Data: Unlimited | Plan: 24 months
A mobile virtual network operator (MVNO) running on Three’s network, iD Mobile is an excellent choice if you’re after unlimited data without breaking the bank. In our most recent in-depth iD Mobile review, we awarded it four stars out of a possible five for its attention-grabbing deals, decent 5G performance and coverage, data rollover feature and free roaming in the EU up to 30GB. Unlike lots of its rivals, iD Mobile has also decided not to introduce mid-contract price hikes.
At the moment, the network is serving up unlimited 5G SIM-only data for just £8/mth for the first six months of a two-year plan. The price will then rise to a still-attractive £16/mth for the remainder of the contract, but make sure you get in there quickly because this half-price deal is unlikely to last for long.
Read our full iD Mobile review
4. Lebara: The best unlimited data SIM for calling abroad
Price: £22.50/mth | Data: Unlimited | Plan: 12 months
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 100 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.
Read our full Lebara review
5. Voxi: The best unlimited data SIM for social media, video and music
Price: £15/mth | Data: 90GB, plus unlimited use of social, video and music apps | Plan: 1 month
Voxi is our favourite mobile network overall, receiving five stars out of five and an Expert Reviews Best Buy award in our latest review, and SIM plans like this are why: for £15/mth on a rolling, 30-day plan, you’ll get 90GB (was 30GB) of 5G-compatible data plus unlimited usage of social media, video and music apps such as Instagram, TikTok, Twitter, Facebook, YouTube, Netflix, Spotify and Apple Music. That’s extraordinary value for money, especially if you spend most of your time on those apps anyway.
In our in-depth write-up of Voxi, we praised the mobile virtual network operator (MVNO) for its dazzling unlimited bonuses, fuss-free plans, rock-solid reliability and consistently high performance. No wonder it also scooped the top prize in the annual Expert Reviews Mobile Network Awards.
Read our full Voxi review
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 you 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 you 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.