Compare unlimited data SIM deals

Best unlimited data SIMs this week

You'll find our pick of the best UK unlimited data SIM-only deals in the table above. All of which have been handpicked by our experts, taking into account price, coverage, speeds, reward schemes and more. 

What are unlimited data SIMs?

Unlimited data SIM cards effectively allow you to use the internet on your phone as much as you like, with no risk of running up high bills for exceeding your usage limit.

They're generally a bit more expensive than plans with usage limits, but that extra outlay means you won't have to worry about running out of data when you most need it. 

Unlimited SIMs are ideal for heavy users. And they're just the ticket if you've got a long commute to work, because they free you to stream endless video or play games online to keep yourself entertained. 

How do unlimited SIMs work?

Much like any other SIM, really. Just sign up, insert it in your smartphone and you're good to go. 

As for whether there are any restrictions on your usage or whether unlimited really does mean unlimited, that's a slightly different question.

In practice, some networks offer 'truly unlimited usage', while others apply usage limits of between 650GB-1,000GB per month. Both of which are so generous that the average person could use their phone all day every. 

Keen to know more about truly unlimited usage on SIMs? Read our guide and we'll explain all. 

Our best unlimited data SIMs this week

Deals change week to week, but here's our hand-picked selection of the best unlimited data SIM-only deals available right now. 

Which networks offer unlimited data SIMs?

Unlimited data SIM-only deals on Vodafone

Vodafone offers two categories of unlimited data plans: Unlimited and Unlimited Max, both of which let you use the internet as much as you like in the UK. There's no fair usage policy to restrict you.

However, it's worth noting that a usage cap of 25GB per month applies on Vodafone unlimited plans when you're overseas. 

The principal difference between Vodafone's selection of unlimited SIM plans are the speeds they offer.

The standard Unlimited plan features average speeds of 10Mbps, while if you choose the top-of-the-range Unlimited Max plan, you'll get access to Vodafone's 5G network and the 'fastest available' speeds. 

All Vodafone unlimited-data SIMs include a three-month trial of SecureNet, as well as inclusive roaming in 51 locations. 

Vodafone also offers Unlimited Entertainment plans. These offer the same unrestricted data usage and speeds as the standard Unlimited plans outlined above, but come with a choice of a 12-month subscription to YouTube Premium, Amazon Prime Video or Spotify. 

Unlimited SIM-only deals on O2

O2 doesn't offer a huge selection of unlimited data SIMs, but they all afford you the freedom to use your phone in the UK without worrying about usage limits or excess charges. 

As is the case with most networks, however, a fair usage cap applies. This limits your data usage to 650GB per month. 

A data cap of 25GB is also in force if you're roaming in destinations in O2's Europe Zone. 

All O2's unlimited data plans entitle you to daily offers with its Priority customer rewards app, as well as free O2 Wi-Fi hotspots. 

And select plans entitle you to a range of O2 Extras. These include six months' free Apple Music or Amazon Music Unlimited, or 12-month subscriptions to Audible, Amazon Prime Video or Calm. 

Unlimited SIM-only deals on Three

Three's unlimited SIMs stand out for being well priced and are all truly unlimited. That means there's no fair usage cap in the UK and you really can use as much data as you like.

And there are no restrictions on how much data you can use for tethering either.

However, a monthly cap of 12GB applies for using your phone when you're in any destination covered by Three's Go Roam in Europe or Go Roam Around the World.

Unlimited data SIMs on SMARTY

SMARTY's unlimited data plans are truly unlimited. This means there's no fair usage cap in the UK and you can use as much data as you like. 

You'll also be able to use your UK allowances in the EU for no extra charge. But a fair usage cap of 12GB per month applies. 

SMARTY SIMs also allow you to tether, so you'll be able to use your plan to get online with other internet-enabled devices, such as a laptop or tablet. 

You can get an unlimited data SIM that comes with unlimited calls and texts, or an unlimited Data Only plan (best suited for tablets or portable Wi-Fi devices like MiFis).

Unlimited data SIMs on iD Mobile

iD Mobile’s unlimited data SIM plan comes with roaming in 50 destinations around the world, though usage is capped at 30GB in these locations. There’s no fair usage policy in the UK, so you can use as much data as you like.

Unlimited data SIMs on VOXI

VOXI is all about unlimited data, so it’s little wonder that VOXI’s unlimited plan has truly unlimited data use.

All other VOXI plans come with unlimited social media as standard, while some also throw in Unlimited Music and Video streaming. This allows you to use social media apps and stream video as much as you like.

However, bear in mind that all plans have a 12GB fair use limit if you’re roaming. But if you buy a European Roaming Pass, you can use your data allowance as normal, or 20GB fair use (whichever is less).

Unlimited Social Media, Unlimited Music and Unlimited Video are all UK-only – so, if you use these whilst roaming, the data will be deducted from your allowance.

Unlimited data SIMs on Lycamobile

With Lycamobile, you can use your data unlimited, but if you exceed 450GB in a 30-day period, it may restrict your speed to 1Mbps.

When using it abroad, you’re limited to 10.5GB.

Unlimited data SIMs on Talkmobile

Talkmobile’s unlimited data SIM restricts your data use in the EU to 5GB (though if you joined the network before 14th March 2023, it’s 15GB). But here in the UK, you’re not limited.

How to find cheap SIM-only deals with unlimited data

You can find cheap SIM-only deals with unlimited data by using our search tool on the right. Click ‘Best SIM only deals’ and you’ll be taken to a new page showing all the best SIM-only deals. Click the ‘Unlimited data’ filter on the left, and you’ll see the best deals with unlimited data.

If you don’t need unlimited data, you can adjust the filter to a high data amount like 50GB or 100GB, which will usually be a cheaper option. Because if you don’t need unlimited data, there’s no point paying the extra for it.

Pros and cons of unlimited data SIMs

The good...

• No need to worry about running out of data 
• No need to worry about excess usage charges, either 

The bad...

• More expensive than SIMs with usage limits 
• Only heavy mobile internet users get through enough data to make them worthwhile 
• Some networks apply speed restrictions 
• Some networks also apply restrictions on tethering 

Alternatives to unlimited data SIM deals

Not sold on unlimited data, or can't find the right deal for you? You have other options. Take a look at...

• SIM-only deals with high data allowances: Nearly all networks offer SIM plans with lots of data, often 100GB and above. These are usually a little cheaper than unlimited data, and still give you more than enough for the odd on-the-go Netflix binge
• Mobile contracts with unlimited data: Want a new phone as well as a SIM? You can get contracts on handsets with unlimited data. Compare phone contracts here
• Using free public Wi-Fi. This means you don't need to pay for unlimited data, but can use Wi-Fi for free when you're out and about

How to switch to an unlimited data SIM plan

To switch to an unlimited data SIM plan, all you need to do is: 

• Check you're out of contract with your current mobile plan
• Choose a new unlimited data deal and sign up
• Cancel your old contract - and port your old number over, if you want to

By definition all unlimited data SIMs have the same mobile internet usage limit (subject to fair usage policies). 

So when you're choosing between them, you're going to want to look at price and customer incentives to help make your mind up. 

Cheapest unlimited data SIMs 

As long as you're not too fussed about sweeteners, such as reward schemes and freebies, you can usually get an unlimited data SIM from just under £20 per month.

Be sure to look out for Three and Smarty, both of whom usually offer very keenly priced unlimited data deals. 

Best unlimited data SIMs with freebies 

O2 and Vodafone offer unlimited data SIMs that get you appealing freebies to go with your bottomless data limit.

But expect to pay a fair bit more for your plan, compared to an unlimited data SIM from a budget network. 

Alternatives to unlimited data SIM deals

Don't need an unlimited

• Pay As You Go SIM Cards
• Affordable SIM Cards
• Best all-round SIM Cards
• Data-only SIM Cards
• 5G-enabled SIM cards

How do I find an unlimited data plan?

To find an unlimited data SIM head to the mobile SIM comparison table on this page and then...

• Adjust the filters at the side to include just those deals with unlimited data, or at least a nice high data allowance
• You can filter for other things too, such as minutes and texts allowances, networks, and budget.
• If you're only interested in unlimited data plans, bear in mind that your options are (ironically enough) a little more limited.

Can I get a mobile contract with unlimited data?

Yes - there are plenty of contracts on handsets that include unlimited data too.

• They're offered by the same networks as above, so once again your options are a little limited, but landing a deal is totally possible.
• You'll find unlimited data plans on a huge variety of handsets, including iPhones, Samsung Galaxy smartphones and more budget-friendly models too.
• It's also worth noting that many networks offer higher data allowances on phone contracts than they do on their SIM-only plans. If you can settle for, say, 20GB or 30GB of monthly data, your options for a contract plan open right up. It's worth considering if you fancy a new phone.

Can I use my unlimited data abroad?

Although unlimited data plans effectively allow you to use the internet as much as you like when you're in the UK, tighter restrictions on your usage apply when you're overseas. 

EE, for instance, allows customers on unlimited data tariffs to use 50GB per month. Meanwhile, Three customers with unlimited data are restricted to 20GB per month while travelling in locations covered by its Go Roam in Europe scheme.  

Is unlimited data really unlimited?

Not always. Most networks have a fair use policy, which puts restrictions on your use. This could be an amount of data that you’re limited to (though it’s usually quite a large amount), or a speed restriction that’s placed on your usage once you exceed a certain amount of data.

For example, Lycamobile will restrict your speed to 1Mbps if you exceed 450GB in a 30-day period.