Unlimited data SIM only deals: best UK networks in 2024
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Compare unlimited data SIMs and read which UK mobile networks' fair usage policies we rate best for being truly unlimited. Last updated: 8th February 2024.
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A better choice than ever
A few years ago, unlimited data almost disappeared off the radar. But network technology improvements have meant the cost of delivering data for mobile providers has come down.
This means more and more networks now offer unlimited data SIM deals than ever. But, like with all plans, there are some finer details on how these work, with fair usage limits and other restrictions on some of them.
In this guide, we rank each network’s unlimited data plans. We find any limits and try to answer whether the SIMs are truly unlimited. We also pick out some key networks for particular requirements.
Three are the best value main network for unlimited data
If you want to join a main network on an unlimited data SIM, our best choice for price is Three. They regularly have the best priced unlimited data deals. See their current options below:
Three have 5G live in these 580+ UK towns and cities. Typical 5G speeds are much faster than other networks according to results from Opensignal and Speedtest who measured speeds between 205.5 Mbps - 286.27 Mbps.
Opensignal also measured typical 4G speeds of 34.5 Mbps, putting Three in second place. These have improved over time and are catching up to the number one network, so speeds are a big strength of Three overall.
There are no speed or fair usage limits while in the UK. We think if you go over 1000GB then Three will make sure your plan isn’t being used for commercial purposes, but realistically this isn’t a limit.
Useful link: Three’s own guide to unlimited data
SMARTY's unlimited data is the most flexible and cheaper
Another provider high up our list for value is SMARTY. They’re owned by Three but run at an arm’s length. They therefore benefit from getting full access to Three's excellent network (check their map here).
SMARTY keep it simple by having only one unlimited data SIM only plan on a 1-month deal with no contracts. You can get this at a lower price by taking the deal SMARTY have shared with us, rather than buying from their site:
On top of that, you get the flexibility to put your SIM in a mobile broadband dongle, tablet, mobile WiFi device or any other device that can fit a SIM. This means you can get the most out of your unlimited data.
There are no speed caps vs being directly on Three (read our SMARTY vs Three guide here). You'll even get access to Three's famously fast 5G on SMARTY.
Useful link: SMARTY’s latest news on 5G launch
iD Mobile: very competitive prices on unlimited data SIMs
As with most their products, iD Mobile have extremely competitively priced unlimited data on phone contracts and SIM only, although SMARTY normally undercut them on 1-month SIMs on the same Three network.
We found no evidence of built in speed limits anywhere on iD’s website for unlimited data and they even say they don’t impose a fair usage limit in the UK. So while you’re at home it’s truly unlimited.
iD now offer 5G data too via the Three network, which currently measures in as the fastest, even though we think EE’s 5G is more widespread. Otherwise you’ll use Three’s 4G, which has massively improved over time.
In all, iD are one of the best networks for taking out an unlimited data plan on SIM only. Just check their coverage in your area before you join, to be safe.
Useful link: Our iD Mobile review
Talkmobile: excellent value on unlimited data
Talkmobile are a smaller provider that use Vodafone’s network and are worth looking at if Three don’t offer good signal near you. They offer identical coverage to their hosts and full speed 4G/5G data on all their plans.
They offer some of the best value deals around and if you shop at the right time you can find an even better unlimited data deal than their regular ones. And there are no credit checks to pass to join them.
There is a general acceptable usage policy in the UK but it's more about not hogging the network in one area, rather than overall usage. You also can't use Talkmobile's unlimited data for any commercial purposes.
Talkmobile are also one of the few networks that still offer inclusive EU roaming. While there you will be limited monthly to 5GB of your data allowance, but for short trips that shouldn't be an issue.
Useful link: Read our full Talkmobile review
Lyca Mobile: low cost and flexible unlimited data SIMs
Lyca Mobile are similar to Lebara in that they offer flexible 1-month unlimited data SIMs with international calls included. But they don’t have any unlimited data deals with unlimited international mins.
They offer 100 international mins on both their 1-month and 12-month unlimited data deals. Their 1-month deal lets you leave your plan whenever, while their 12-month contract gives you a better monthly deal.
Lyca claim that they will investigate and may even suspend your services if they think you’re using your SIM for commercial purposes. You’d have to use loads of data for them to think this, however.
They’re the best value network for unlimited data on EE’s network, even if they don’t offer full 4G access (here’s why). If you need to call abroad they’re an excellent choice, if you don’t they’re still worth considering.
Useful link: See all of Lyca Mobile’s SIM only plans
Lebara: unlimited data SIM deals with international mins
Lebara offer a few unlimited data plans that include either 100 or unlimited international minutes or come on either 1-month or 12-month contracts. Each of these comes with a different cost.
Their most expensive plan is their unlimited plan with unlimited international minutes on a 1-month contract, while their cheapest comes with 100 international minutes on a 12-month contract.
Lebara now offer a 12-month unlimited SIMs that include unlimited international minutes. While they get beat on price by some networks, the inclusive international calls might just make them worth it for you.
While their unlimited SIMs don’t technically have limits, they’ll look into your usage if they think you’re using your SIM for commercial purposes. But you’d have to use a huge amount of data for them to do so.
Overall, we think Lebara are the best option out there if you need to call abroad often. If not, there are other providers that beat them on price and might be better options for you.
Useful link: All providers that use Vodafone’s network
Vodafone: watch out for speed caps on unlimited SIMs
Vodafone offer lots of different unlimited data plans, each with a different cost, speed limit and number of added benefits on top, with all of them tending towards the higher end of the price range:
Their Unlimited Lite plan limits you to 2 Mbps, their Unlimited plan limits you to 10 Mbps and their Unlimited Max plans don’t limit your speeds. Typically, the lower the speed cap the lower the cost of the plan.
So on Unlimited Max you’ll get access to Vodafone’s fast typical 5G speeds between 114.3 Mbps - 146.19 Mbps according to Speedtest by Ookla and Opensignal. That puts them in second place of all networks.
If you’re looking to go abroad, it’s worth looking at Vodafone’s Unlimited plans with 3 Xtras. These are premium deals with added benefits and are the only way to get inclusive roaming (read their guide).
For us, their Unlimited Max plan is the best as there’s no point getting unlimited data if you’re slowed to a crawl. But there are cheaper providers on Vodafone’s network that are worth considering.
Useful link: Our full Vodafone review
EE: decent network, expensive unlimited SIMs
If you’re after unlimited data, because you want to use a lot of data as you travel around the country, we think EE are a very sensible choice. They offer unlimited data on phone contracts and SIM only:
EE’s prices are the biggest downside of taking one of their unlimited SIMs. They have the best 4G signal of all networks (check coverage here) with the fastest typical 4G data speeds, but these come at a high cost.
Opensignal measured typical 4G data speeds of 40 Mbps on EE. Typical 5G data speeds sit between 99.5 Mbps - 108.91 Mbps according to Opensignal and Speedtest by Ookla, putting them in third place.
As long as you use your SIM for personal use, there are no speed limits or fair usage caps on EE. So if you want to invest in quality, an EE unlimited data SIM gives the best overall experience in our view.
Useful link: Read our full EE network review
Honest Mobile: a clear unlimited data fair usage policy
If you’ve not heard of Honest Mobile, read our review here. They’re a carbon negative network, using Three (and sometimes backed up by O2/EE when their Smart Signal system is in operation).
They’re honest about their fair usage limit on their unlimited data deals. Each month you can use up to 650GB of full-speed data. After that they’ll cap your data speeds at 3G-level only.
If you want unlimited, because you’re worried about going over limits, this is fine. There’s still no way you can pay extra for data usage in the UK. It’s just you’ll be slowed down.
Honest offer 5G access on all plans, giving their users full use of Three’s brilliant 5G network. If their speed cap isn’t too big of an issue, Honest are a genuinely good choice for unlimited data.
Useful link: Honest Mobile’s network FAQs
O2: higher priced SIMs with slower data speeds
If you’re in the market for unlimited data, you’re more than likely quite an expert user that wants to rip through as many gigabytes as you can each month and have a quality network experience.
O2’s 4G signal is widespread, but a bit weaker than some networks in the countryside. The big downside of O2’s network for unlimited data users is their 4G data speeds, which sit at 20.9 Mbps in Opensignal’s report.
The same goes for 5G, with typical speeds between 77.0 Mbps - 78.88 Mbps according to results from Opensignal and Speedtest. You can get it in a massive 2000+ locations, but you won’t exactly go speeding ahead.
If you catch it while there’s an offer, O2 unlimited data SIMs can compare quite well on price:
O2 say they’ll investigate your usage if you go over 650GB twice in one year to make sure it’s for personal use. But this isn’t a cap. O2’s unlimited plans are good but are held back by their underwhelming speeds.
Useful link: O2’s guide to their 5G
spusu: a more flexible alternative to joining EE
spusu are a smaller provider who offer full access to EE’s call (3G/2G) and data (4G/5G) signal (check here). They usually offer low prices, but oddly their unlimited data SIM only deals are higher in price than EE’s.
That unfortunately makes them one of the most expensive networks for unlimited data. But they do offer great flexibility on their plans with 1-month deals you can leave whenever if you find it’s not working for you:
They also include 500 mins to EU numbers, which can save you quite a lot if you need to call abroad often. But there are other networks on this list that offer inclusive minutes abroad on better value deals.
spusu may investigate you if they think you’re using more data than is reasonable for personal use, but it’s very rare that they’d do so. They’re not a bad choice for unlimited data, just an expensive one.
Useful link: Our full review of spusu’s network
VOXI: flexible unlimited data SIM plans
VOXI are a sub-brand of Vodafone and as such offer full access to the entire Vodafone network and the fastest possible speeds. Join at the right time to get a healthy price on their unlimited data SIM:
If you look at the right time you can get a better deal on unlimited data. What’s even better is they’re on 1-month plans without contracts or credit checks. But other budget networks and longer deals can beat them.
There is an acceptable usage policy on VOXI but it’s less a personal limit on the number of gigabytes you can use, more about usage that disrupts the network for other users (hogging bandwidth in one locale).
We think if you’re genuinely using VOXI for your own personal use, you should never fall foul of this. We’re happy to describe it as a truly unlimited data deal.
Useful link: All VOXI benefits
giffgaff: truly unlimited data only comes at a higher cost
For a long time, the only unlimited plans giffgaff offered on SIM only and phone deals were called Always On plans. These let you use as much data as you wished, but limited speeds after you used up 80GB.
It’s still available and is fine if you just want the reassurance of not having any data limits to exceed. But if you know you’re a massive data user, it’s not really for you. Here’s the latest price on SIM only:
But now they do also offer a truly unlimited data plan. It’s more expensive than Always On and it isn’t particularly cheap compared to other networks. But it’s 5G on the O2 network:
As giffgaff use O2’s network, they’re not a particularly great choice for unlimited data users. While both 4G and 5G coverage is widespread, their data speeds are a bit of a let down (read our review here).
They also have the same “650GB twice in a year” fair usage policy as O2, where they’ll investigate if you go over that limit. So they’re not exactly good when it comes to speeds, prices or a lack of restrictions.
Useful link: Get £5 free credit
ASDA Mobile: built in speed caps on decently priced plans
ASDA are worth considering when looking for a short-term unlimited data SIM only plan on Vodafone’s network. Their 1-month deals compare quite well on price, but they are still beatable:
There are three separate unlimited plans on ASDA, each with a different data speed cap. We’d steer clear of the 2 Mbps cap plan though, as that’s barely enough to support video streaming.
The 10 Mbps one could be useable. That’s typically enough for video streaming but you wouldn’t want to use it if you’re someone that wants big downloads, fast. For that, you’d want the 150 Mbps capped unlimited plan.
You also don’t need to pass a credit check to join ASDA’s unlimited data deals since you pay up front for your mins, texts and data each month. So if you have a poor or no credit history they’re a good choice.
Useful link: See ASDA Mobile’s unlimited data page
Tesco Mobile: get unlimited data abroad until 2025
Tesco Mobile offer unlimited data on long-term, but low-cost SIM only contracts. You can take a 12-month or a 24-month contract, but their 24-month contracts tend to work out as better value.
Tesco have promised to keep their inclusive EU roaming until the end of 2024. That’s excellent for unlimited data users as they have no roaming fair usage policy, so there’s no data limits at home or in the EU.
And while they’re beatable on price, taking a Clubcard (which is free) lets you take better deals called “Clubcard prices”. They sometimes offer unlimited data deals on these, but they change now and again.
Their main downside is their speeds. They use O2’s network and as such have typical 4G speeds of 20.9 Mbps according to Opensignal and 5G speeds between 77.0 Mbps - 78.88 Mbps according to Opensignal and Speedtest.
Useful link: Tesco Mobile’s guide to their unlimited data plans