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Unlimited data SIM deals

Most of us work our smartphones pretty hard – social media, watching TV, downloading music and online shopping.

With the whole internet to explore, an unlimited data SIM could keep you connected without worrying whether you'll run out of data. But is uncapped mobile data necessary and are these data packages really the best value for you?

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What is an unlimited data SIM only deal?

An unlimited data deal allows you to use the internet on your mobile (or tablet) without having to worry about exceeding your data limit – and, in turn, avoiding hefty extra charges. It also means you don’t need to worry about finding somewhere with Wi-Fi to stay online anymore.

Unlimited data SIM deals include:

  • Unlimited 4G or 5G data
  • Unlimited minutes
  • Unlimited texts.

Simply pop the SIM into your mobile or tablet, then download, text and call as much as you like. Unlimited data deals are available on pay monthly SIM only plans and pay as you go services. You can also opt for an unlimited data plan when you get a contract for a new phone.

Which networks do unlimited data deals?

The following networks currently offer unlimited data deals:

  • Asda – comes with 5G up to 150 mps at no extra cost, one month rolling contract. Uses the Vodafone network.
  • giffgaff – specialise in rolling monthly deals, with unlimited data plans available.
  • iD Mobile – unlimited data available on a 12-month contract or rolling monthly plan.
  • Lebara – uses the Vodafone network and offers 100 International mins to 42 countries in its 30-day unlimited plan or to 44 countries in its 12-month unlimited plan.
  • O2 – one of the ‘big four’ UK networks, O2 offers both 12-month and 18-month unlimited data plans.
  • SMARTY – offers a rolling monthly contract with unlimited data for endless browsing with added flexibility.
  • Three – Three specialise in unlimited data plans, with rolling monthly and 12-month contracts available.
  • Virgin mobile – exclusive to existing customers only, Virgin mobile offers 12-month unlimited data plans.
  • Vodafone – another of the ‘big four’ networks, Vodafone offer unlimited data on rolling monthly, 12-month, and 24-month plans.
  • Voxi – exclusively offer rolling monthly contracts, with unlimited data available.

Pros and cons of monthly contract and SIM only unlimited data deals


There are some very obvious advantages of having an unlimited data SIM:

  • You can stream, download and browse as much as you like
  • You don’t need to worry about running out of data or when your allowance resets
  • No extra charges for using data.


Unlimited data plans are typically more expensive than limited plans. You should also be aware of any terms and conditions your provider may have in place, such as:

  • Fair usage policies
  • Tethering caps or allowance
  • Roaming data charges
  • Speed caps.

Your contract should clearly state if your provider has a fair usage policy and what it is. If you have any doubts about how much data you should be using, then 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 and find a deal in minutes.
To find a deal that’s right for you, choose a mobile phone plan or SIM only plan. We’ve included a handy filter so that you can narrow down your search. Simply choose ‘unlimited data’ and you’ll get a list of all SIM deals offering unlimited data.


The cost of unlimited data SIM plans can vary depending on the type of deal you’re on. What probably won’t surprise you is that 5G deals tend to be more expensive than their 4G equivalents, but that’s not always the case.

To see if the cost of an unlimited data deal is worth it, think about your typical usage and how frequently you’ve run out of data and had to pay to top up. Then compare the total with the cost of an unlimited data plan.

Also check whether your provider has an inflation clause that allows them to increase the price mid contract. With high inflation rates you could find your bill rising steeply if this is the case. Around a third of mobile customers don’t know whether their provider can increase their price.

Price will also depend on whether you’re getting a new phone on a monthly plan or choosing a SIM-only deal for your existing phone.

Contract length

When looking for a good SIM deal for unlimited data, decide whether you want a flexible, rolling monthly plan, or whether you’re happy to lock yourself into a longer-term deal.

We compare a range of SIM only unlimited plans, as well as monthly plans if you want a new phone. Each has a selection of contract lengths to suit your needs:

  • One-month contract – these unlimited data, pay-as-you-go SIM only plans offer the most flexibility, allowing 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 can be more expensive than longer contracts.
  • 12-month contract – while less flexible than a rolling monthly plan, these year-long contracts often reward you with a cheaper deal for locking yourself in for longer.
  • 24-month contract – these are usually offered as part of a phone plan, but 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 you lose out on flexibility. If a better deal comes along in a month or even a year, you won’t be able to switch without paying a fee to cancel your contract early.

Text and call minutes

Texts and call minutes are usually unlimited on an unlimited data plan. So if you’re weighing up a plan with limits against an unlimited data plan, make sure that you’ve got enough texts and call minutes to suit your needs. Checking an old bill should give you some idea of your typical usage.

Unlimited social data

If you're addicted to social media and messaging, a plan that offers unlimited social data but doesn't include video and streaming is an option. There aren't as many deals to choose from and some may cover only one or two apps, but they tend to be cheaper than all-in plans. It means you can scroll, swipe, snap, tweet, post or chat to your heart's content – or at least until any screen-time limiting apps you've installed kick in.


Some deals will throw in a free gift like headphones, a games console or a voucher. But don't opt for a deal because of the freebie if the plan doesn't suit you.


The big four networks (EE, O2, Three and Vodafone) have almost nationwide coverage, but some smaller networks may not, so it’s worth checking. It’s also worth checking which networks have local indoor and outdoor coverage – particularly if you live somewhere remote. Try the Ofcom coverage checker. It will help you see if 5G is available too.


If you’re planning on using your phone abroad, check how any roaming charges apply to your unlimited plan. You don't want a nasty shock when you come home to discover a bill for something you thought was included.

Do I actually need unlimited data?

Whether you actually need unlimited data depends on your average monthly usage. Around 73% of data connections are made over WiFi rather than a mobile network, according to telecom regulator Ofcom. Check out your data usage stats, which can be found in your phone’s settings.

The UK average data use is 5.6GB over the course of a month, and one third of users only use between 500MB and 2.5GB per month. So if you fall into one of these groups, paying for unlimited data perhaps isn’t worthwhile. However, if your limit is around 20GB and you find yourself exceeding this every month, an unlimited data deal might be worth it.

A few mobile phone providers have calculators that help you understand how much data you need, 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?

There are large but limited data deals available. These can offer top limits of 100GB or 120GB of data so it might be worth checking to see if you can find a large but limited deal that's cheaper than unlimited.
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 – especially if you want to upgrade to a 5G model to maximise data speed. There are plenty of deals around, 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 also offer a higher data allowance with unlimited minutes and texts on their phone contracts. So if you want a new phone and are happy with a fixed amount of data a month, this might work out better for you.

Frequently asked questions

Can I use my unlimited data abroad?

It depends – some providers offer data use abroad as part of their unlimited contract deals. For example, Three offers unlimited data deals including ‘Go Roam’ at no extra cost with its Advanced plans.

Other providers may restrict the limit when you go abroad, so always check the plan details before you sign up if you want unlimited data abroad.

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 SIM market is very competitive, which means it’s easy to find a cheap deal. Although offers are always changing, when you compare with us, we show the lowest cost at the top. It's simple to spot the cheap unlimited data deals.

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 some networks will have limits, so you should check the terms and conditions of your contract, or ask your network provider.

Can you get unlimited pay-as-you-go deals?

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 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 your 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?

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. 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.

Do I need unlimited calls and texts as well?

Popular messaging services, such as WhatsApp and Skype, let you text, phone or videocall for free using Wi-Fi or 4G. However, there will always be times when internet access is not possible, in which case, you’ll need to phone or text the traditional way.

Having unlimited minutes and texts may not be necessary for you, but most unlimited data plans will include them anyway.

Will I need a credit check to get an unlimited SIM plan?

Some deals require a credit check, while others don’t. A traditional 12 or 24-month contract will normally involve a credit check. More flexible plans, like pay as you go or rolling monthly plans, can offer a pre-paid service that avoids a credit check being run on you. If in doubt, it’s always best to check with the network before signing up for a plan.

When you compare with us, you can look out for plans that say "no credit checks" in the results, if this matters to you. But make sure you can afford your monthly payments.

Author image Sajni Shah

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."

- Sajni Shah, Utilities comparison expert

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Correct as of March 2024.