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Best SIM-only deals: Our pick of the best SIM-only deals in the UK this January

Edward Munn Max Figgett
24 Jan 2022

The top SIM-only deals this January, from all the top mobile network providers

With so many options to choose from, finding the best SIM-only deals can be tiresome and confusing. With more and more people choosing to go for a SIM-only plan these days, we've done the heavy lifting to find you the best deals available in the UK this month.

As you can see from our at-a-glance list below, deals start from less than £10 a month, but if you're willing to stretch your budget a little, you'll benefit from more data and other perks. Indeed, spending more often results in better value for money, but if you don't use much data, you'll still easily find a good that won't break the bank. On average, a £10 SIM-only deal gets you around 10GB of data, which is enough for most users.

With so many mobile service providers to choose from, you're bound to find a deal that suits you in terms of price, data, and speed. Below our at-a-glance list, you'll find our in-depth selection of the best SIM-only deals in ten different categories. After this, you'll find our guide on how to choose the best SIM-only deal for you.

Best SIM-only deals: At a glance

The best SIM-only deal this January

Vodafone: 100GB of data for JUST £9.50/mth

This attention-grabbing deal from gets you 100GB of Vodafone data for just £9.50 per month instead of the usual price of £13 per month on a two-year contract. This is an unmissable offer that also includes unlimited texts and minutes. You'll need to claim the money back via cashback, but the process is simple and full instructions can be found by clicking the link below.

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The best SIM-only deals in the UK

1. Three: The best-value 12-month deal

Price: 100GB of data for £12/mth | Get this deal

You'll be hard-pushed to find much better deals than Three's 12-month SIM-only plans. Indeed, for just £12/mth you can get yourself a SIM card with 100GB of data and unlimited minutes and texts. That's more than enough data for most people but if you want unlimited data, you can have that for a mere £4/mth extra at £16/mth.

Key details - Contract length: 12 months; Total price over contract: £144; 5G-ready: Yes; Freebies: Unrestricted tethering

Buy now from Three

2. Smarty: The best budget SIM-only deal

Price: 4GB for £6/mth | Get this deal

This deal from Smarty is the cheapest one available at the time of writing and a great offering if you're mainly at home and only use your smartphone sparingly. That said, you still get unlimited calls and texts, so if don't mind having a small amount of monthly data (only 4GB), this deal is worth looking at. If that's not quite enough data for you, for an extra £1 a month you can get 8GB.

Key details - Contract length: One month; Total price over contract: £6 (rolling); 5G-ready: No; Freebies: Unrestricted UK tethering, EU data roaming

Buy now from Smarty

3. VOXI: The best deal with free social media and streaming

Price: 15GB for £10/mth | Get this deal

Most of us use our mobile data to browse social media websites or access streaming services such as YouTube, Netflix and Amazon Prime Video. Voxi has a brilliant solution because it offers free social media browsing and streaming service usage. Its network is provided by Vodafone to ensure reliable 4G or 5G coverage. As well as this 15GB for £10/mth deal, you can also pick up 30GB of data for £15/mth and an unlimited plan for £35/mth.

Key details - Contract length: 30 days; Total price over contract: £10 (rolling); 5G-ready: Yes; Freebies: Unlimited video streaming and social media, free EU roaming

Buy now from Voxi

4. EE: The best deal for reliable network speed

Price: 160GB for £20/mth | Get this deal

EE has consistently been voted the best mobile network in the UK. You can currently grab a hefty 160GB of monthly data from EE for £20 per month as part of the provider’s 5G plan. For most people, this is as good as unlimited data because you'll be hard-pressed to use up that much data unless you stream content every day outside the confines of Wi-Fi.

This contract also allows you to share data with your family, so if you've got kids who guzzle down data quicker than you do, simply transfer data between each phone for no additional cost. It gives you access to EE's range of smart benefits, allowing you to choose between a free Apple Music subscription, BT Sport, an unlimited video streaming data pass and free-roaming abroad.

Key details - Contract length: 24 months; Total price over contract: £480; 5G-ready: Yes; Freebies: Superfast 5G

Buy now from EE

5. BT Mobile: The best deal for BT sport

Price: 40GB for £20/mth | Get this deal

This deal includes 40GB of data, unlimited minutes and texts for £20/mth on a two-year contract, while BT will also throw in its BT Sport app, meaning you can stream all of your favourite sport on the go. The app alone is worth £10 per month, making this an amazing deal if you want to watch BT Sport.

Key details - Contract length: 24 months; Total price over contract: £480; 5G-ready: No; Freebies: BT Sport app (worth £10/mth), data roaming in 47 countries

Buy now from BT

6. Vodafone: The best deal for 5G speeds

Price: Unlimited 5G data for £25/mth | Get this deal

Vodafone has the best offering when it comes to fast 5G. This unlimited 5G data deal costs £25 per month for two years. With this contract, Vodafone promises to give you the fastest available data connection, allowing you to make HD video calls, stream music in high quality, and download or update apps on the go without any trouble.

Key details - Contract length: 24 months; Total price over contract: £600; 5G-ready: Yes; Freebies: 51 roam-free destinations

Buy now from Vodafone

7. O2: The best SIM-only deal for freebies and roaming

Price: 250GB data for £22/mth | Get this deal

O2 has a platter of SIM-only deals, with this one including up to six months of free Disney+, Amazon Prime Video, Amazon Music or others. For reference, Disney+ costs £8 per month so that itself equates to £48 in savings. You can also get free roaming in 75 destinations, including the US, which is very rare to find at the moment. This is great if you tend to travel a lot because it means you won't have to worry about using your phone abroad.

Key details - Contract length: 24 months; Total price over contract: £528; 5G-ready: Yes; Freebies: 6 months of Apple Music, 6 months Disney+, free roaming in 75 destinations

Buy now from O2

8. Lebara Mobile: The best deal for free calling abroad

Price: 15GB for £15/mth | Get this deal

If you have friends and family living abroad, this deal from Lebara (which runs on Vodafone's network) is a great way to keep in touch with them. Not only is it contract-free, but you get unlimited international minutes free to over 40 countries, covering the US, Australia and a large portion of Europe and Asia.

Key details - Contract length: 30 days; Total price over contract: £10 (rolling); 5G-ready: No; Freebies: Unlimited international minutes to 41 countries

Buy now from Lebara Mobile

9. Sky Mobile: The best deal for Sky customers

Price: 10GB for £10/mth | Get this deal

Sky TV is considered to be one of the best UK TV service providers. Its basic packages start at £25 per month, but this gives you access to the entire gamut of channels. The benefit of choosing Sky Mobile is that you can stream Sky content on your mobile without eating into your monthly data allowance and any unused data automatically rolls over to the next month. You can also share your data with up to seven SIMs, so if you're running out of data and your kids have some left (or vice versa), you can move data about to save you buying more.

Key details - Contract length: 12 months; Total price over contract: £120; 5G-ready: Yes; Freebies: Unlimited streaming on Sky apps, unused data is rolled over

Buy now from Sky Mobile

10. Giffgaff: The best deal for students

Price: 16GB data for £10/mth | Get this deal

Students are always looking to save money in whatever way they can, so you'll be delighted to find this bargain monthly Goodybag from Giffgaff. It gets you 16GB of data and unlimited texts and minutes for the same price as their normal 10GB package – perfect for when you're out and about in lectures or when you fancy checking in with your family back home. Better still, you'll get £5 cashback when you refer a friend.

Key details - Contract length: 1 month; Total price over contract: £10 (rolling); 5G-ready: No; Freebies: £5 cashback when you refer a friend, 1GB extra data/month after 3 months

Buy now from Giffgaff

11. iD Mobile: The best deal for rollover data

Price: 50GB data for £7.50/mth | Get this deal

The name of the game here is decent data packages at low prices, and with this deal, iD Mobile certainly hits the mark. Normally £12, the monthly premiums for this contract can be brought down to just £7.50 via cashback redemption. This is a little extra work, but full details can be found on the website, and for the amount you end up saving, it's worth putting the effort in. If that wasn't enough, iD Mobile also offers data rollovers on all contracts, meaning that any spare data you don't use up in a month simply rolls over into the next month at no extra charge.

Key details - Contract length: 12 months; Total price over contract: £96; 5G-ready: No; Freebies: Data rollover, Roam like at home in 50 worldwide destinations

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How to choose the best SIM-only deal for you

What is a SIM-only deal?

A SIM card is the small chip that you insert into your phone to tell it who you are and what mobile phone plan you are on. It stands for subscriber identity module and is used to authenticate the user’s information, including a special number that identifies the phone on the network.

As the name suggests, a SIM-only plan covers the cost of the SIM – and, therefore, the cost of being on the network – but not the phone it slots into. That means you’ll need to provide your own handset, whether that’s a case of buying it outright or using a previously owned smartphone.

As you’re only paying for the SIM (and whichever benefits you might get on your specified plan), these contracts tend to be substantially less expensive than their phone counterparts. This makes sense, given that you’re not paying off the price of the handset in addition to the network costs.

Pay monthly or pay as you go?

In this guide, we’ll be covering monthly SIM-only contracts, but it’s worth mentioning the alternative: pay as you go. With these plans, there’s generally no contract and you’re not tied into a given time period with the network provider. Instead, you get a certain amount of minutes, texts and data, and when you run out you can top up your SIM card by choosing to pay a set fee.

We’d recommend a pay-as-you-go plan if you don’t think you’ll be using your phone much, at least not so much that you’ll regularly go through the allotted minutes, texts and data within a month. If you do, you won’t necessarily be saving any money over a monthly plan. Essentially, the benefit of a pay-as-you-go plan is flexibility – not being tied to monthly payments for 12 or 24 months. But that benefit falls away if you end up making monthly payments anyway, probably for a smaller data allowance.

What to look out for when buying a SIM-only deal

Data offerings

There are SIM-only deals with limits on minutes and texts, but these days many plans tend to be unlimited in these regards. Instead, the crux of a contract is its data offering. How much data do you get access to each month? Does the plan have a limit on its data speed?

With the first question, one key thing to consider is how much data you actually need on a monthly basis. An unlimited data plan might bring peace of mind that you won’t run out of internet juice, but it might not be the most cost-effective choice if you actually use less than 30GB.

We have some tips on judging the amount of data you need, but a good starting point is to see how much data you currently use, which can be easily done either via your network provider or your phone. You can do this on an iPhone by going to Settings | Cellular or Settings | Mobile Data. On Android, go to Settings | Network and Internet | Data Usage. See what you currently burn through in a month and use this as a yardstick for judging what your future data needs might be.

In terms of data speeds, this is an easy-to-miss factor that can have a big impact on your overall experience. Vodafone, for example, has a trio of unlimited data plans, but the lowest tier (Unlimited Lite) has a maximum download speed of only 2MB/sec. So while it might not have a cap on overall data usage, this is essentially a cap on the speed you can hope to achieve when using your phone. As a point of reference, Netflix recommends a minimum download speed of 3MB/sec for HD streaming.

Contract length and lifetime cost

Besides data, the next thing you’ll be keeping an eye on is the length of the contract you’re signing up to. Some last 24 months, while others only last 12. If you think you’ve found a good deal, you may want to consider locking it in for a longer period of time. Alternatively, if you like the flexibility of being able to change providers, a shorter plan may be for you. Remember, since you’re not paying off the cost of a handset, your contract will only be paying for the minutes, texts and data plan you’ve picked.

The lifetime cost is the total amount you’d spend over the contract length, and it can be a great way to judge the brutal reality of whether or not you’re saving money. Take a few minutes to plot out the amount you’d spend across the 12 or 24 months for different plans, and compare the results. Some SIM-only contracts might be half price for the first six months, for example. That’s great, except for when the monthly cost skyrockets after that period. Does it even out in the end, or do you actually end up spending more?

Another important thing to consider is the cost of the handset. This will very much depend on your particular situation, but if you’re buying a phone outright you’ll want to factor in that cost when calculating the lifetime total. In a nutshell: is the cost of the handset plus the lifetime cost of the SIM-only contract cheaper or more expensive than the lifetime cost of a monthly phone contract?

Benefits and freebies

Finally, some providers will dangle bonuses to try and tempt you into certain contracts. Sometimes these can be good deals, but often they will be a tactic to convince you into a more expensive contract. That’s not to say you should avoid a tantalising freebie – just look at it through the lens of your lifetime cost.

EE, for example, offers a number of "smart benefits" as part of select contracts. These range from access to Apple TV+ or BT Sports Ultimate, to bonus "free" roaming destinations. Are these things you would actually want to buy otherwise? Taking the freebies out of the picture, would you opt for the contract without them? Added extras might sweeten an already good deal, but just remember to look at them critically as part of an overall balance of costs.

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