Best unlimited data SIM only deals in December 2023

Unlimited data SIM only contracts

Are you looking for a SIM with unlimited data? We’ve got loads of great options for you to choose from to enjoy all the data you could want.

If you don’t want any limits on how much data you can use on your smartphone, a SIM only bundle with unlimited data might be the best deal for you.

All top UK networks now provide unlimited data plans to fit a variety of budgets. So all you need to do is pick the deal that suits you best.

Let’s dive into all the info on unlimited data SIM deals.

How to choose the best unlimited data SIM deal

If you frequently use your mobile to stream Netflix on the move, download hefty playlists for long commutes or are a big gamer and social media addict, an unlimited data SIM is definitely worth considering.

Unlimited data SIM cards allow you to use your mobile phone to get online as much as you want. So there’s no danger of getting cut off for going over your allowance or receiving extra charges when your bill comes at the end of the month.

If that sounds like the kind of SIM deal that you need, the next thing to do is start comparing deals across networks.

Different mobile phone providers will offer unlimited data deals at different prices and contract lengths.

Some may even include benefits like freebies and inclusive data roaming. So once you’ve found a deal that ticks all your boxes, you’ll be ready to pull the trigger and get yourself a SIM deal with unlimited data.


What is an unlimited data SIM?

Unlimited data means exactly what you think it does – unrestricted, limitless data. You’ll be able to use the internet on your smartphone as much as you like. Enjoy endless TV streaming binges, never-ending Spotify playlists, marathon Tik Tok sessions and anything else you like to do with your mobile phone.

If that sounds good to you, next time you look for a SIM only deal, bypass offers that provide 10GB, 20GB, or even 100GB – and click on the deals that say unlimited GB. Then you’ll never run out of data on your smartphone. 

If you’re a heavy user who runs out of data on your current plan, you probably end up paying extra at the end of the month. With an unlimited deal, you’ll only ever pay the amount you’ve agreed at the start of your plan. 

How do unlimited data SIMs work?

Unlimited data SIM only deals work just like any other SIM. When you sign up for a plan, you’ll get a SIM card that you simply need to put in your phone to start using. Your data allowance will automatically come into effect. And you’ll be free to get through as many GBs as you want. 

Do you need unlimited data?

Whether or not you need unlimited data comes down to your usage habits. If you’re a big-time data user who often runs out of GBs before the end of your monthly billing period then unlimited data could be ideal for you. It’s worth digging into your patterns of use by logging into your network’s app or your online account. This will let you check your data consumption over the last few months. If you’re regularly using large chunks of data that aren’t covered by your current deal, think about going unlimited. 

Such deals are also ideal if you simply want the freedom of never running out. 

Which networks offer unlimited data SIMs?

All of the best UK networks provide unlimited data deals. Here’s a quick look at what they offer:


British Vodafone Broadband logo on a phone broadband not working internet down

Vodafone offers unlimited data deals with different levels of download speed – like you get with broadband packages. They are completely unlimited, without fair usage restrictions.

Additionally, you can choose an Xtra Plan. This lets you roam in 83 countries for free. However, there is a data cap of 25GB.


VOXI logo

If you’re big on social media, VOXI is ideal. All its plans include unlimited social media usage as standard. That means you can use social media sites and apps without making a dent in your data. And if you want that freedom over the whole internet, you can simply choose the network’s unlimited data plan. 


EE offers a variety of unlimited SIM plans on 30-day,12 and 24-month data contracts. They all provide fantastic speeds, as EE is frequently highlighted as the UK’s fastest mobile network.

EE’s plans also come with some great perks. Some plans offer Inclusive Extras, which allow you to choose from BT Sport or Netflix subscriptions, Microsoft 365, Xbox Game Passes and more. 



SMARTY’s unlimited data package is available on a rolling month-to-month basis, with no restrictions or speed limits. It also provides completely unrestricted hotspot tethering.

It’s also very reasonably priced, making it an excellent choice for people who are on a tight budget. And you aren’t required to undergo a credit check to be eligible for it.

EU roaming is free too, albeit with a 12GB fair usage limit in place.


O2 store logo

O2 offers a selection of unlimited data plans available for 30-day rolling deals or longer-term 12-month and 24-month contracts.

Benefits included with some deals include free roaming in 75 countries (including the US and Australia) in addition to EU roaming. Also, plans include three-month free subscriptions to entertainment platforms like Disney Plus, Amazon Prime, Apple Music and more. 

O2 has a fair usage policy but it only comes into effect in extreme situations. Like if you use more than 650GB numerous times or if you frequently tether more than 12 devices to your smartphone. 

In addition, if you roam, you’re limited to 25GB while abroad.


giffgaff logo hero image

The ultra-flexible giffgaff 30-day plans are available with unlimited data. And they’re all 5G-ready and include EU roaming (up to 5GB per month) for free.  

Its fair usage policy states that you should not tether your phone to over 12 devices or use more than 650GB of data multiple times in six months.


Three phone store

Three’s unlimited SIM options are reasonably priced and available in 30-day, 12-month or 24-month contracts. Furthermore, all plans are genuinely unlimited and include 5G at no extra cost.

You can also take advantage of Three+ rewards, a loyalty programme for customers that provides special promotions at a variety of high-street retailers and eateries.

What are the benefits of having unlimited data?

The benefits are clear – mainly you’ll simply never have to worry about running out of data. That means you can watch as much streaming content as you like, listen to all the playlists, scroll through all the social videos and stay connected online at all times. 

It also means you won’t have to worry about accidentally exceeding your data limit and getting extra charges on your bill. Not to mention the comfort of knowing you’ll always have data to use whenever you need it. 

Alternative SIM only plans

If you’ve decided you don’t need an unlimited data SIM only deal after all, there are still plenty of alternative options available. You can choose from a wide range of data bundles ranging from low 5GB to high 100GB and sign up for short rolling plans or longer contracts. 

You can choose SIM deals that include 5G, roaming or extra bonuses. Compare SIM only deals across all networks today to find a deal that fits what you have in mind. 

Is there truly an unlimited data SIM plan?

Yes, although some providers impose fair usage policies, others have genuinely unlimited data plans. This means there are absolutely no limits on the amount of data you are able to use each month.

However, even if there is a fair usage limit on your unlimited data deal it will likely be so large that even heavy users will struggle to hit it.

That said, it’s always a good idea to double-check your network’s terms of use before you sign up.

Can I get unlimited 5G data?

Yes, most major networks, like Vodafone, Three, O2, iD Mobile and more, all offer free 5G connections with all of their unlimited data deals. The only thing you need to activate the 5G is a 5G-ready phone and you must physically be in a location that has 5G switched on. 

Can I use my unlimited data SIM abroad?

This comes down to your network’s roaming policy. While some networks continue to provide roaming as a benefit of their SIM contracts, the majority of major networks have stopped providing free EU roaming.

There will typically be a fair usage limit on the amount of data you are able to use while travelling. This limit could range from 5GB to 25GB per month. If that’s the case, you won’t be able to use unlimited data overseas, even if it’s part of your plan. 

For further flung trips, only a few networks provide international roaming if you’re going outside of the EU, often in the form of add-ons. 

If I have unlimited data, do I need Wi-Fi?

Short answer – no. You won’t need to connect to Wi-Fi on your smartphone to get online if you get an unlimited data SIM deal.

However, in some cases, Wi-Fi connection might be faster or stronger than your mobile data. And, in certain situations, you may not get any mobile signal at all, such as on the London Underground and other mobile blackspots. If this is the case, a Wi-Fi connection will certainly come in handy. 

Am I limited to how much data I can hotspot if I have unlimited data?

This is entirely dependent on your network. Some will limit the amount of gadgets you can connect to a hotspot, whereas others won’t. Have a look at your network’s terms of use to get an idea of  its hotspot policies. 

Can I get a mobile contract with unlimited data?

Yes, all the major UK networks – like Vodafone, EE, Three, O2, Sky Mobile, and iD Mobile – offer unlimited data deals with their mobile phone contracts. You can choose one of the latest devices like the iPhone 15 or Google Pixel and enjoy unlimited data to stream, scroll and share as much content as you want.