Unlimited data SIM deals
With the whole internet to explore, an unlimited data SIM could keep you connected with no need to top up your data.
Read our guide to discover whether an unlimited data plan could be the best value for your browsing needs.
What is an unlimited data SIM only deal?
A SIM-only deal with unlimited data lets you go online with your smartphone or tablet and never have to worry about exceeding your allowance. This way, you can avoid any hefty extra charges.
Having unlimited data also means you can keep on using the internet even if your Wi-Fi drops off or you can’t find another connection.
SIM-only deals with unlimited data may include:
- Unlimited 4G or 5G data
- Unlimited minutes
- Unlimited texts.
Simply pop the SIM into your mobile or tablet and you’re free to download, text and call as much as you like. Unlimited data plans are available on pay-monthly SIM-only deals and pay-as-you-go services.
You can also choose an unlimited data plan when you get a contract for a new phone.
Which networks do unlimited data deals?
The following mobile providers on our panel currently offer unlimited data deals:
- Asda Mobile
- Giffgaff
- ID Mobile
- Lebara
- Lyca Mobile
- Mozillion
- O2
- Sky Mobile
- Smarty
- Spusu
- Talkmobile
- Tesco Mobile
- Three
- Vodafone
- VOXI
Pros and cons of monthly contract and SIM only unlimited data deals
Pros
You can enjoy some big advantages with unlimited data:
- Stream, download and browse online as much as you like
- No need to worry about running out of data or wait for your allowance to reset
- Extra data use charges won‘t apply.
Cons
However, there are potential drawbacks to unlimited data plans:
- Prices tend to be more expensive than for limited data plans
- You could find a ‘fair usage’ policy in place despite it being ’unlimited’
- Watch out for tethering and speed ‘caps’. This means you could face a limit on the amount of data you can use for tethering (when you share your phone’s mobile data with other devices)
- Roaming data charges. If you don’t choose an unlimited data deal that includes data roaming, you may face added charges when you use your phone outside the UK.
Your contract should clearly state if your unlimited data plan has a fair usage policy and, if so, be clear about what it is.
If you have any doubts about how much data you should be using, contact your provider.
How to find the best unlimited data SIM for you
Whatever your data needs and budget, let us do the searching for you. Simply use our comparison service to explore our best data-only SIM deals in minutes.
Comparing deals is one of the easiest ways to find the best unlimited data plan for your browsing needs and budget. We’ve included a handy filter so that you can quickly narrow down your search.
Simply choose whether you want a SIM-only or contract deal, then filter to select ‘unlimited data’.
When comparing unlimited data plans, make sure you consider the following:
Price
The cost of unlimited data SIM plans can vary depending on the type of deal you choose. For example, an offer with 5G tends to be more expensive than its 4G equivalent, although it’s not always the case.
You could also find price differences between a SIM-only deal for your existing phone and what it might cost as part of a monthly contract with a new phone.
Start by working out if it could be good value for you by looking at past bills to see how often you’ve paid to top up your data. Add it all up and then compare it to the cost of a new unlimited data plan.
Under new Ofcom rules, from January 2025 telecoms providers must make their pricing and any potential rises transparent at the point of sale.
Contract length
When looking for the best unlimited mobile data deals, think about how long you’d like your deal to last.
Is a flexible, rolling monthly plan important to you? If not, and you’re happy to lock yourself into a longer-term unlimited data plan, you might get a better deal.
We compare a range of SIM-only unlimited data phone deals, as well as monthly plans if you want a new phone. Each offers a selection of contract lengths to suit your needs:
- One month – these unlimited data, pay-as-you-go SIM-only plans offer the most flexibility. They allow you to end your deal and swap to another after just a month. If you’re happy where you are, the contract simply rolls on. Because of this flexibility, they tend to be more expensive than longer fixed contracts.
- 12 months – less flexible than a rolling monthly plan. However, year-long contracts often reward you with a cheaper deal for locking yourself in.
- 24 months – these are usually offered as part of a new mobile phone contract (though you can get them for SIM-only deals too). Again, you can be rewarded with a cheaper price for locking yourself in for a longer term. But if a better deal comes along, you won’t be able to switch without paying a fee to cancel your contract early.
Text and call minutes
You can usually make as many calls as you like and send any number of texts with an unlimited data plan. If you’re weighing up a plan with limits versus one with unlimited data, make sure that you’ve got enough texts and call minutes to suit your lifestyle.
If you’re not sure how much you might need, a look at your old bills should help to give you an idea.
Unlimited social data
If you love to spend lots of time on social media and enjoy chatting on a variety of lifestyle apps, you could consider a limited data deal with a twist - it includes ‘unlimited social data’ that doesn‘t count towards your other data allowance.
Slightly cheaper than general ‘unlimited data’ plans, they let you use your monthly data allowance elsewhere online.
There aren’t as many deals to choose from, and some may cover only one or two social media apps. But it means you can scroll, swipe, snap, tweet, post or chat to your heart's content, and not worry you’ll run out of data or face extra charges.
Freebies
Some deals will throw in a free gift, such as headphones or a voucher. However, try not to be tempted by a freebie if the plan doesn‘t suit you. Think of it as a bonus instead, if you were already going to pick that plan regardless.
Network
The big four networks (EE, O2, Three and Vodafone) have almost nationwide coverage. Some of the smaller providers rent space from these networks so they can provide services all over the country. Use a network coverage checker to see the coverage where you live, work and make regular visits.
It’s also worth checking which networks have local indoor and outdoor coverage. This is particularly important if you live in a remote location.
Try the Ofcom coverage checker. You can also use it to see if 5G is available in your area.
Roaming
If you’re planning on using your phone abroad, check what – if any – roaming charges apply to your unlimited data contract.
Some providers offer data use overseas as part of their unlimited contract deals.
However, others may restrict it so always check the plan details before you sign up.
Do I actually need unlimited data?
Whether you need unlimited data depends on how much you use on average each month. You can check your data usage stats in your phone settings. Or look at your past bills to see what you typically use.
The average UK data usage is 8.0GB a month, according to Ofcom’s 2023 Communications Market Report - a big increase on the 5.6GB recorded in 2021. And with the growing availability of 5G networks, that figure is likely to keep rising.
If you’re not sure how much data you’re likely to need, a few mobile phone providers offer calculators that can help. Your suggested data needs are based on the balance of browsing, videos, texts, social media, video and music streaming you do.
What’s the best alternative to an unlimited data SIM?
Messaging services such as WhatsApp and Skype let you text, phone or videocall for free using Wi-Fi. For many, this means keeping in touch without eating into a data allowance can be easy.
For those who like the security of a decent data plan, there are large but limited data deals available. These can offer top limits of 100GB or 120GB of data and may be a cheaper option than an unlimited data deal.
If you use lots of data but don’t want a SIM-only deal, a good alternative would be a handset contract that includes unlimited data too. This could work for you if you want to upgrade to a 5G model to maximise data speed.
There are plenty of offers to look at, including handset deals on big names such as Apple iPhone and Samsung.
If you’re more interested in unlimited calls and texts than data, many networks tend to offer a higher data allowance with unlimited minutes and texts if you sign up for one of their phone contracts.
Frequently asked questions
Can I get a 5G unlimited data SIM?
Yes, 5G unlimited data SIMs are available, but only with some networks. The ‘big four’ (EE, O2, Three and Vodafone) each offer 5G. But other smaller networks may not.
This means you have fewer networks to choose from, so compare providers to find one that offers what you need.
Which company has the cheapest unlimited data plan?
The provider of the cheapest unlimited data plan changes all the time. But the SIM market is very competitive, which means it’s easy to find a cheap deal.
When you compare with us, we show the lowest price at the top to make it simple to spot our best unlimited data deals for your budget.
What is a hotspot?
A hotspot lets you connect your phone and other mobile devices to the internet via Wi-Fi when you’re out and about.
Some hotspots are attached to a physical location – a café or a railway station, for example. But you can also use your own phone to create a personal mobile hotspot, which lets you connect other devices, such as your laptop or tablet, to the internet at the same time. You do this by using Bluetooth or your phone’s mobile data.
Am I limited to how much data I can hotspot if I have unlimited data?
Some networks will let you hotspot as much data, on as many devices, as you’d like. But other networks will impose limits. Check the terms and conditions of your contract or ask your network provider.
Can you get unlimited pay-as-you-go deals?
Yes, you can. If you don’t want to be tied to a long contract and you’re happy with your current phone, a pay-as-you-go SIM with unlimited data is also a good alternative.
Does my phone have to be unlocked?
Mobile companies have been banned from selling locked handsets since December 2021.
If you have an old handset that needs to be unlocked to accept an unlimited data SIM, you’ll need to contact your old provider. This should be free if you’re out of contract.
But remember, if you switch to a different provider before your current contract ends, you may be charged a penalty for leaving your mobile contract early.
Can I keep my old number if I change network?
To keep the same number, you’ll need to contact your old network provider and request a 9-digit number PAC (Porting Authority Code). They should send the code within two working days.
You won’t be able to use your old number if it’s disconnected, so make sure you get the code and change over before you cancel your old contract.
What SIM card size will I need?
The size of SIM card you’ll need will depend on your handset. There are three types of SIM:
- Standard (15x25mm)
- Micro (12x15mm)
- Nano (8.8x12.3mm)
Older phones will usually have a standard SIM while newer phones are more likely to need a micro or nano SIM. Be sure to let your new unlimited data plan provider know which type of SIM you need.
Will I need a credit check to get an unlimited SIM plan?
Some unlimited data deals require a credit check, while others don’t. A traditional 12 or 24-month contract will normally involve a credit check.
More flexible SIM-only data deals, such as pay as you go or rolling monthly plans, can offer a pre-paid service without a credit check. If in doubt, it’s always best to check with the network before signing up for a plan.
Do I need Wi-Fi at home if I have unlimited data?
The likelihood is that you won’t need Wi-Fi if you have an unlimited data package, although most households already have it through their home broadband service.
And there may be times when you can’t connect to 4G or 5G networks at home if there’s a technical problem, and Wi-Fi could come in handy.
What our expert says...
"An unlimited data deal gives you the additional benefit of being able to use your phone as a Wi-Fi hotspot. To find the right deal for you, shop around and compare unlimited deals with plans that have a large data allowance."
- Matthew Brewer, Broadband and mobile expert
Why use Compare the Market?
Find a deal in less than 1 minute[1]
We compare leading SIM data providers including Asda, Giffgaff, O2, Sky Mobile and Tesco Mobile.
[1] Correct as of March 2025.