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21 January 2021

Best Sim-only deals: Sky, Plusnet, ID Mobile, Giffgaff and more

Browse our pick of the best Sim-only deals for low, medium and high data users, including 5G Sim deals that won't tie you down
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Hamse Yusuf

Finding the right Sim-only deal can seem daunting – with a range of data limits to choose from, and some tying you down for as much as 24 months, you’ll need to make sure you choose a package that best serves your needs. 

We regularly scour the market to pick what we believe to be great value Sim-only deals across low, medium and high-data packages.

Find out how to get started, browse some great deals, and decide what other considerations you need to take into account.

See where you provider ranks in the Best and worst UK mobile networks for 2021 based on our in-depth customer survey.

How much mobile data do I need?

With most packages now coming with unlimited data and minutes, the main factor driving the price of Sim-only deals is mobile data. In terms of how much data you need, consider how often you use your phone outside your home or place of work (which are both places where you're likely to connect to a wi-fi network). 

Also, it's important to note the types of activities you do on your phone. If you only use mobile data for light browsing you needn't pay a lot, but if you like to stream on-demand video on your commute, you'll need a bigger bundle. That's why we've split the best deals into low, medium and high data. We've also included 5G data deals – bear in mind the fast speeds of 5G may mean you use more than you expect.

Best low data Sim deals

These deals have an allowance of up to 3GB and will be suitable for people who mainly use their phone through a wi-fi network, or don't use the internet often. This amount of data should be plenty for browsing, light social media use or instant messaging on services such as Facebook, Instagram or WhatsApp. All deals have unlimited minutes and texts.

Sky Mobile

  • Data Allowance: 2GB
  • Contract Length: 12 months 
  • Network signal: O2
  • Price: £6 a month 

Sky Mobile is currently offering 2GB data with unlimited minutes for £6 a month, plus Sky TV customers get unlimited access to Sky TV apps without using up any data.

Sky customers can 'rollover' their data for up to three years with its Piggybank scheme, so if you're a really light user you can save the data you don't use each month for a time when you need it.

Check out Sky Mobile's Sim-only deals and read our Sky Mobile review to see how it fares in our survey.

Plusnet Mobile 

  • Data Allowance: 3GB
  • Contract Length: 1 month rolling
  • Network signal: EE
  • Price: £6 a month 

Plusnet Mobile is currently running one of the best deals, offering 3GB data for £6 a month on a monthly rolling contract.

As a no-frills, low-cost mobile network, there is not much in the way of extra features or benefits but otherwise represents a good deal, and importantly, it doesn't tie you down.

Check out Plusnet Mobile's Sim-only deals and read our Plusnet Mobile review to see how it fares in our survey.

Best medium data Sim deals

These deals have an allowance of between 4GB and 10GB and are suitable for people who often use their phone when out and about, whether that be for social media, music streaming or internet-based voice/video calls. All deals have unlimited minutes and texts.

iD Mobile 

  • Data Allowance: 4GB
  • Contract Length: 1 month rolling
  • Network signal: Three
  • Price: £6 a month 

As a mobile network owned by Carphone Warehouse you may be forgiven for not knowing much about iD Mobile, but it regularly offers some great low-cost deals.

iD Mobile also offers data rollover if you do not use your monthly allowance

Check out iD Mobile's Sim-only deals and read our ID mobile review to see how it fares in our survey.

Virgin Mobile 

  • Data Allowance: 10GB
  • Contract Length: 1 month rolling
  • Network signal: EE
  • Price: £8 a month 

Virgin Mobile is one of the oldest virtual networks and regularly offer good deals. 

With an EE signal, you should expect a very reliable signal with good coverage, but check out Mobile phone coverage map to see how it looks where you live.

Check out Virgin Mobile's Sim-only deals and read our Virgin Mobile review to find out how it fared in our regular survey.

Best high data Sim deals

These deals have an allowance of 10GB and above and are suitable for people who use their phone a lot when out and about, whether that be to stream high quality video/music on a commute or for creating a wi-fi hotspot for a laptop or other internet devices (if the network provider allows). All deals have unlimited minutes and texts.

iD Mobile 

  • Data Allowance: 20GB
  • Contract Length: 1 month rolling
  • Network signal: Three
  • Price: £10 a month 

iD Mobile makes another appearance in our roundup and this time, it is offering 20GB for just £10 a month.

As with its 4GB package, you can rollover your data if you do not use all your allowance. 

Check out iD Mobile's Sim-only deals and read our ID mobile review to see how it fares in our survey.

Giffgaff 

  • Data Allowance: 80GB
  • Contract Length: 1 month rolling
  • Network signal: O2
  • Price: £20 a month 

Giffgaff is well known as a low-cost mobile network and this deal represents a good price for the huge 80GB data package.

There are not many additional benefits, but you get access to the O2 network which should provide a good signal for most.

Check out Giffgaff's Sim-only deals and read our Giffgaff mobile review to see how it fares in our survey.

Best 5G Sim deals

These deals allow you to access lightning-fast 5G speeds – provided you live in an area with good 5G coverage and own a 5G phone. All deals have unlimited minutes and texts.

O2

  • Data Allowance: 12GB
  • Contract Length: 12 months
  • Network signal: O2
  • Price: £10 a month 

O2 is currently offering 12GB of 5G data for just £10 a month with new customers also getting six months of Disney Plus for free.

O2 customers can also access O2 priority for discount, deals and offers with its partners.

Check out O2's Sim-only deals or read our O2 mobile review to see how it fares in our survey.

Three

  • Data Allowance: Unlimited
  • Contract Length: 1 month rolling
  • Network signal: Three
  • Price: £24 a month 

There are not many unlimited 5G deals on the market and this one from Three comes in at a very attractive price. Even better, you only have to commit to a rolling monthly contract.

Three customers also get Go Roam, where you can access up to 12GB of 4G data and your allowance of minutes and texts in more than 70 countries.

Check out Three's Sim-only deals or read our Three mobile review to see how it fares in our survey.

How to get the best deal on a new mobile contract 

There are a range of things to consider when shopping for a new Sim-only deal.

Work out if you’ll benefit from promotions

You’ll need to decide whether you prefer to be on a rolling monthly plan that offers the flexibility of changing at any time, or tying yourself down to a contract period – typically 12 or 18 months. Usually, longer contracts represent better deals. Providers might offer money off the usual monthly fee as part of a promotion, or a data boost for the same price. 

You might also see streaming services added in at no extra cost – in the past, Vodafone has offered a choice of Amazon Prime Video, Spotify, NOW TV and Sky Sports Mobile with its Entertainment bundles. Compare and contrast though – if you won’t use the extra data, or the streaming service, you may still be better off with a rolling monthly Sim, if you can get it at a good price. 

Find out How to keep track of your mobile data and minutes to help work out how much data you really need.

Are you better off with a phone on contract?

There are also a lot of great contract deals, so if you’re in the market for a new phone, it’s worth looking at these as well. If you can afford to purchase a handset outright and get a Sim-only deal, it’s often cheaper in the long run, but this isn’t always the case. 

Use our mobile phone contract calculator to compare deals when you see them and read our guide on How to buy the best mobile phone on contract 

How good will network reception be?

Signal is another consideration. If you know that a particular network is good for your area, you may want to stick with it, but move to a different provider. Or if it isn't, it could be time to move. Check the chart below to see which core networks the virtual providers use. 

Do you need 5G?

As the new super-fast standard, you'll probably be itching to try out 5G if you have a compatible phone. Our Mobile phone coverage map can help you work out if it's in your area. Browse our 5G-compatible phone reviews if you don't already own one – you can now find models for less than £300. Or for more information, read our guide to 5G.

Should you stay with your mobile provider or switch?

If you’ve found a deal that you like, but you’re otherwise happy with your provider, you might be a bit reluctant to switch. You could try haggling with your mobile provider to see if they can match or better the deal, but if they won’t, switching might be your best option. Fortunately it’s pretty easy to do – our guide on how to switch mobile network provider explains how. 

Get to know your new provider Before you switch, it’s worth looking into your new provider to make sure they tick the boxes. We regularly survey customers of 13 major mobile networks to find out their views on everything from customer service and ease of contacting the provider. 

Read our detailed mobile provider reviews for more information on your provider.