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Best Unlimited Data SIM Only Deals

Find cheap SIM only deals with no data limits.

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Best Unlimited Data SIM Only Deals

Unlimited Data SIM Only

Having unlimited data available to you on your smartphone may seem unnecessary, but there are many of us nowadays who like to enjoy full use of our phones wherever we go. If you like to stream, listen to music and browse the internet constantly then removing the data cap on your phone may be the way to go. Read our useful guide to find out more about unlimited data SIM options and discover the best deals available right now.

Do I need unlimited data?

There are various options for you when it comes to unlimited SIM deals and it can be confusing when deciding which is the right deal for you. The basic types of unlimited SIM deal are as follows:

  • Contract SIM only: A SIM for mobile phones with minutes, texts and data over a 12-month contract period.
  • Pay-as-you-go SIM only: A SIM for mobile phones where you pay for your personal usage of minutes, texts and data. They provide a flexible way to pay for your mobile phone usage.
  • Data-only SIM only: SIM cards for tablets, laptops and personal hotspot devices that only offer data, and include no minutes or texts.
  • 30-day SIM only: SIMs that are similar to PAYG SIMs, but instead offer 30-day ‘bundles’ where you have a monthly allowance of minutes, texts and data.

Whether you actually need an unlimited data SIM depends entirely on how you use your mobile device. Before deciding to buy unlimited data, it is a good idea to work out exactly how much data you use monthly. If your current limit is low at around 5GB and you have never exceeded it, then you probably won’t need unlimited data. However, if you already have a large data limit, say 20GB, and you find yourself running out of data a lot, then unlimited data is something you should consider. Some reasons you may want unlimited data are:

  • You don’t want to worry about running out: It isn’t that expensive to have unlimited data and it means that you never have to think about using your phone on the go. You have the peace of mind that you have no data limit and can use the internet as much as you want.
  • You stream or game a lot: If you are someone who uses their mobile device to watch a lot of television, listen to music and play games that require the internet, then it’s likely that you will be burning through your data rapidly! Unlimited data means that you can do all of these things without having to worry about a limit.
  • You need maps: Using map services such as Google or Apple Maps requires data. If you regularly use maps for long drives, running or cycling then your data can disappear quickly, and unlimited data could be the answer.

Which networks offer unlimited data SIM only deals?

Until recently, a few of the larger network providers didn’t have unlimited data deals, but now there are plenty of options available. A few providers still don’t offer unlimited data plans including Asda Mobile, BT Mobile, Plusnet Mobile, Sky Mobile and Tesco Mobile. Here are the networks that have unlimited data options:

  • Three: One of the first networks to offer unlimited data. Their SIMs are well priced and are available as one month, rolling contracts or 12-month deals.
  • EE: Flexible unlimited data plans with extra benefits such as BT Sport or passes for other streaming services. EE is also often named best network for its speed and coverage.
  • O2: Has an unlimited SIM only deal that offers unlimited calls, minutes and data. Unlimited data SIMs generally start at around £30 and include exclusive offers through O2 Priority.
  • Vodafone: Many unlimited data SIM only deals available. Multiple offers also available depending on the plan you choose, such as free subscriptions to Spotify, Now TV and Amazon Prime.
  • SMARTY: SMARTY is a sub-network of Three, but still has plenty of great unlimited data SIM only deals to choose from.
  • Virgin Mobile: Offers an unlimited data SIM only deal to their Virgin Media broadband or TV customers.
  • VOXI: Operates on the Vodafone network. Provides a plan called ‘Endless data’ which is 5G-ready.
  • iD Mobile: Has limited unlimited data SIM only deals, so it may be better to stick with the larger networks unless you are already with iD.
  • giffgaff: Offers 30-day SIM only deals which roll on each month, so you can choose to upgrade or downgrade your plan at any time.

How much does it cost to get unlimited data?

Unlimited data SIM only deals are the most expensive SIM only plans that you can buy, but this doesn’t mean that you can’t afford them.

Use our price comparison table above to find affordable unlimited data plans.

Why should I go SIM only?

SIM only deals provide a great way to save money on your mobile phone and stop you from getting stuck in long contracts. If you don’t need to upgrade your mobile, then getting a SIM only deal is an affordable, flexible way to continue using the phone you want the way you want.

Even if you do want a new phone it may be cheaper to buy the phone and the SIM separately, depending on the phone and the SIM only deal you choose of course. With unlimited data, take the iPhone as an example – you can get locked into a 24-month contract that will cost you around £1,500 over two years. Instead, you could buy an iPhone up front for around £1,000 and pay for a SIM only deal that over two years would cost you far less.

Best unlimited SIM only deals

Let's take a look a look at the best unlimited SIM only deals currently on offer from each provider:

Best Three unlimited SIM only deals

Provider Contract length Monthly cost
Three Mobile 1 month £30 See deal
Three Mobile 12 months £19 See deal
Three Mobile 24 months £18 See deal

Best O2 unlimited SIM only deals

Provider Contract length Monthly cost
O2 1 month £36 See deal
O2 12 months £33 See deal
O2 24 months £30 See deal

Best Vodafone SIM only deals

Vodafone international SIMS

Provider Contract length Monthly cost
Vodafone 1 month £37 See deal
Vodafone 12 months £27 See deal
Vodafone 24 months £26 See deal

Best unlimited SIM only deals from other providers

Provider Contract length Monthly cost
VOXI PAYG £30 See deal
iD Mobile 1 month £16 See deal
iD Mobile 12 months £16 See deal
iD Mobile 24 months £16 See deal

Frequently Asked Questions

What SIM card size do I need?

There are three sizes of SIM card – standard, micro and nano. Your network provider or retailer will help you choose the correct size so you shouldn’t have to worry.

Is my phone unlocked?

If your existing mobile was bought with a traditional contract, then it may be locked to the network provider. If the contract has ended it is easy and free to unlock the phone so you can use it with a different deal. If it is locked then be aware that unlocking can take up to 10 days and can cost up to £15 to complete, depending on your situation.

Can I keep the same number?

If you are switching deals, then it is possible to keep the same mobile number. Just make sure that you request your PAC (Porting Authorisation Code) from your old provider before you leave.  You can then give the PAC to your new provider within 30 days of your new deal and they will switch your number within one working days.

Can I use unlimited data abroad?

Your unlimited data plan will allow you to use the internet as much as you like when you’re in the UK, but unfortunately this won’t be the case when you’re overseas. Your data limit abroad will depend upon what plan you have chosen and which network you are on. Read our useful guide on International SIM card deals here for more information on the best SIM deals for travelling.

Last reviewed: 06 July 2023

Next review: 06 August 2023