The best SIM only deals in January 2021

SIM only deals are an excellent option for a wide range of people, quickly gaining popularity in the UK for their affordability, flexibility and as a great alternative to a phone contract.

Whether you’ve bought a SIM-free phone or your contract is up and you’re not ready to separate from your handset, SIM only deals can give you the option to give your phone a contract on your own terms.

And while it used to be just EE, Vodafone, Three and O2, a wide range of new networks are now available too, making the number of choices available to you wider than ever.

This means you can go for the downright cheap options, the flexible 1-month rolling plans, the ones with a massive amount of data or the ones with added incentives like free subscriptions or cashback.

Below we’ve listed the ten best SIM only deals currently available, as well as some key information on buying a new SIM plan like key networks, changing your number and more.

The absolute best SIM plan right now:

What is a SIM only deal?

A SIM only deal is a contract that rewards you with a SIM card. When you choose a SIM plan you decide the data, calls, texts and network that you are on as well the contract length and price you are willing to pay.

Who has the best SIM only deals?

Three: best for big data and unlimited plansEE: best for fast speeds and overall performanceVodafone: strong balance of affordability and featuresO2: heavy on the added benefitsSmarty Mobile: best value 1-month rolling optionVoxi: best for social media users 

SIM only deals: top 10 of the week

1. The best cheap SIM plan

2. Best 5GB+ data SIM

3. Best 30-day SIM plan

4. Best big data SIM (20GB+)

5. Cheapest unlimited data SIM only deal

6.  Best EE SIM plan

7. Best Vodafone SIM plan

8. Best O2 SIM only deal + free Disney Plus

Voxi SIM | 12-month contract | 12GB data | Unlimited calls and texts | £10 per month + free social media
Find yourself powering through data because of social media apps? Voxi is likely going to be the best network for you. With this plan, you get 12GB of data while only paying £10 a month to get it. On top of that, Voxi doesn’t use up any data when using social media apps. That means you can use Facebook, Whatsapp, Twitter and more without fear of running out of data. The same goes for streaming apps like Netflix.
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10. Best data only SIM deal

Three | 12-month contract | 10GB data | £14 per month
If you use your tablet as a kind of portable TV for catching up with Netflix, iPlayer and Amazon Video while out and about, then this Three data only deal just got even better. You now get 10GB for £14 a month (sorry, it has just gone up in price), which is cheaper than other major networks. This is the best value SIMO we can find for using data on an iPad or one of the other best tablets.
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Should you get a SIM only deal?

What is the best SIM only deal?

Right now, this is actually quite an easy one to answer as Three’s awesome £16 per month for unlimited data tariff tops the best SIM only deals out there. That’s a scarcely believable price in the name of Black Friday and also nets you unlimited calls and texts.

Want to pay a little less? Three also has a very tempting £6/pm for 4GB data offer if you’re trying to get your bills as low as possible, while up-and-comer Smarty hits the sweet spot somewhere in between with this 50GB data for £15 a month deal.

sim card

Is a SIM plan the best option for you?

A SIM plan is the perfect option for a number of people and you likely fit into one of a few categories:

– SIM-free phone and SIM plan:
You’ve realised that if you have the cash upfront to pay for it, a SIM-free phone is going to be cheaper in the long run than a phone contract.

Once you’ve bought a SIM-free handset, you’ll then…yep, you guessed it – need to invest in a SIM plan to go with it.

– Your contract is up:
This is the other likely option. You took out a two or three year contract and now that it is up, you’ve decided you want to hold onto your phone. In this case a SIM plan can allow you to continue using that device.

SIM only deals

Is a SIM plan cheaper than a phone contract?

It can be. Teaming a SIM only plan with a SIM-free phone could save you a few quid, especially if you catch a big discount. It’s usually the case when a flagship phone hits the market and contracts are made deliberately expensive.

Not all the savings you can make are as extravagant, and on big data it’s frequently more cost effective to dive into a contract instead. But if you can afford to splash a few hundred pounds up front then the savings over the next couple of years could well be worth it.

What kind of SIM plan do you need?

SIM only deals

What SIM card size do I need with SIM only deals?

It used to be the case that you would need to do some detailed research to see which size SIM card you would need for your phone but recently most networks switched over to Combi SIM cards.

These are SIM cards that are all three sizes and you simply break it down to the size you need. While that sounds fiddly and complicated it is actually extremely simple.

If you do come across a network that does not use these Combi SIM cards, there are three sizes:

– Standard (15x25mm) – Micro (12x15mm) – Nano (8.8×12.3mm)

The majority of recent phones, especially flagships, now use Nano cards.

SIM only deals

(Image Sky Mobile)

Can I get 5G SIM only deals?

You can indeed! In fact, many SIM plans now automatically provide both 4G and 5G including Vodafone and Three. However, for a number of other options you’ll have to pay more for 5G.

EE, Voxi, GiffGaff, BT and more all offer some deals with just 4G and others that offer both 4G and 5G. It is also crucial to mention you’ll need a 5G phone to get 5G with your SIM.

While a number of devices now offer it including Apple and Samsung’s most recent range of phones and many OnePlus handsets, a wide array of other handsets aren’t there yet.

A number of networks also don’t have 5G networks yet and could take awhile to get there. Smarty Mobile, iD Mobile, Virgin and many more could take until late 2021 for their networks to go live.

Check out our 5G SIM only deals guide to learn more.

SIM only deals

What length contract should I get with SIM only deals?

There is a good few options when it comes to the length of SIM only deals. While the most common option you’ll see is 12 months, there is now a wide range of 30 day SIMs as well from the likes of Voxi, GiffGaff and Smarty.

There is also the occasional 24 month contract but these are a lot more rare than the above. These do often offer discounted prices though if you’re willing to stick around for longer.

SIM only deals

How much data do I need?

Because you can change your plan up more regularly than a normal, lengthier contract, it’s less crucial to get this nailed from the start. But if you’re thinking of grabbing a 12-monther or just put a personal pride on getting things right first time, then we’ll help you pick out the sweet spot of data for you.

Firstly, check your phone to see how much data you’ve been using to date, and whether you have the tendency to use more than your current allowance every month. Then, if you’re still unsure, check out our guidance: 

0-1GB Tiny amounts of data could be a blessing or a curse. If you’re putting it in a rarely used phone that will scarcely be away from wi-fi then you’re quids in. But if you end up with one because your head’s turned by the incredible price, then you could end up paying more if you continually go over your allowance.2-3GB For anybody who needs data for little more than the occasional Google Maps route planning, 2GB and 3GB plans come cheap and give you much more freedom to check the football scores and scroll Facebook away from the wi-fi without danger.4-8GB If you can’t leave the house without having a music streaming service like Spotify pouring into your ears, then it might be worth paying for some extra GBs of data.10-16GB This is a significant amount of data and some networks offer it for a very appetising price. Whether streaming music, downloading podcasts, watching social media videos, or all three is your thing – you should be covered.20-30GB Only smartphone junkies that need regular (and hefty) data fixes need bother with this avalanche of GBs. You’ll be able to rinse Netflix, Spotify and online games without too much fear of topping out.Unlimited Maybe it’s because you use remarkable amounts of data. Maybe it’s because you simply don’t want to keep checking how much data you’ve used every month. Whatever your reason to go unlimited, you have only two choices when it comes to network: Three or GiffGaff.

SIM only deals

Do I need unlimited calls and texts?

This question is practically obsolete now as the large majority of SIM only deals will provide unlimited calls and texts anyway. For the small amount that don’t, you’ll likely be getting in the range of 500-5000 minutes and a few thousand texts.

Due to the fact that these kind of contracts are rare, we wouldn’t worry too much. If you do come across one with a smaller cap and it feels right for you, take a look at how many texts and calls you’ve used in the past.

What’s the best mobile network for SIM only deals?

While EE, O2, Vodafone and Three are generally considered the major four networks for contract plans, when it comes to SIM only there are some other key players are well worth a look. See what we think of them below, and whether you’ll get any free perks to help persuade you to sign up. Plus, we’ll tell you about a couple of other SIM sellers that might be able to wrangle you an even better deal.

Which networks have coverage in my area?

It’s one of life’s (many) little frustrations – you sign up with a network, get your SIM up and running and then discover that you get no coverage at all in your house. Well this little pain in the neck can be avoided by using the dedicated coverage checker that most networks provide. Enter your postcode and you’ll see whether your address has 2G (calls, texts and email), 3G (the basics plus picture messaging and faster web browsing) and 4G (all the powers of 3G, plus faster downloads, online gaming and media streaming) coverage.

Switching to a new SIM plan:

unlocked mobile phones

Is my phone unlocked and can I use a new SIM in it?

The times have passed since most phones were locked to a network and you had to pay a dodgy backstreet ‘engineer’ to unlock it. Nowadays, it’s standard practice for networks to let you use whatever SIM you want in the phone as soon as you’ve paid up the original contract (or earlier if you pay them a fee) – and Three ships all its handsets unlocked from the outset.

The good news is that if you’re phone does turn out to be locked to a network, it is easy to fix that. The bad news is that most networks make you pay for the privilege. Insert a friend or family member’s SIM into your phone to see whether it’s already unlocked and, if it isn’t, look for your network below to see how to cut ties with them:

EE Once six months have gone by on your contract, you can call EE on 0800 956 6000 and pay them £8.99 to unlock your phone. It says it will take around 10 days to complete. PAYG phones can be unlocked for free. Both iPhones and Google devices unlock for free after a certain time with EE.O2 Whether you have an iPhone or Android device, pay as you go or on a contract, O2 can unlock it for free. You simply need to log into the O2 app, select unlock my phone and you’re good to go.Three Fear not, all phones on Three are unlocked as standard. Shove whatever SIM you like in there, it will work a treat.Vodafone The red network doesn’t quite get the same marks as Three, as your phone will be locked to them on arrival. But they have made unlocking handsets absolutely free within 10 days of your request.

telephone numbers

How do I keep my old number?

Ever heard of PAC codes and wondered what a classic 80s arcade game had to do with telephone numbers? It actually stands for Porting Authorisation Code, and it’s the set of digits that you need to grab from your old network to let you transfer over your existing mobile number.

The great news is that the process is a lot easier these days. Now you can text your provider and they will text your pac code back to you. They have to reply within a minute and the code will last for a full 30 days.

You then give your code to your new provider and your number has transferred. You can find out more with our guide to Text To Switch.

What if my current contract hasn’t finished yet?

If you’re in the position where you plan to leave your current contract to get a new SIM plan, what will happen will depend on your individual contract and how long you have left.

In the large majority of cases, you will be required to pay off the existing time. If you still have six months left, you will have to pay six months worth in one go for example.

This is usually not advised unless you only have one or two months left and you’re simply looking to get a new plan as soon as possible.

SIM only deals by network

If you want fast and furious 4G, then your choice has to be an EE SIM deal. Its speeds are around 50% faster than the other major networks, which is really noticeable if you like watching films or football on the move. And EE gives you three free months of BT Sport, as well as six months of Apple Music and a host of other free subscriptions.

O2 has a lot to offer. Along with the fact that many of its plans lead the way for pricing, it has recently started offering a six months subscription to Disney Plus across a number of its best plans. On top of that it offers free Wi-Fi hotspots across the country, great coverage and its Priority rewards app with discounts, free tickets and more.

Vodafone feels like one of the most well-rounded providers of SIMs. It offers affordable prices on a lot of plans and packs in a number of benefits. Most importantly is its VeryMe app which provides discounts, competitions and a free gift every Friday – the perfect competition to O2’s Priority scheme.

Three has the major benefit of being the cheapest of the four main networks. It provides the lowest cost on unlimited data, cheap plans and pretty much everything in between. While it no longer has the Wuntu app to compete with Vodafone and O2’s reward scheme, it offers great travelling and roaming perks.

iD Mobile:
iD is a good option if bargain basement prices are what you covet most. This is a network run and owned by Carphone Warehouse – it piggybacks on the Three network. It’s an excellent option if you want great value on a rolling monthly contract.

Smarty is one of the newer players in the world of SIM only deals but one with a lot of benefits. Not only is it extremely affordable but it also provides tethering abilities and all of its contracts run on 1-month rolling contracts so you can leave at any time. It piggybacks off of the Three network so will have reliable coverage across the UK.

That familiar old stalwart of telecommunications BT is so-so when it comes to SIM only tariff prices. That’s unless you’re already a BT broadband customer, in which case you get some really favourable prices – a fiver less than the rest of the hoi polloi. Plus, you usually get a BT Reward Card with the majority of plans that can be spent anywhere that accepts Mastercard, the value of which depends on how much data you’re in for.

GiffGaff regularly offers some of the cheapest SIMO deals out there. They don’t give you much of a data allowance to play with, but if you just want to keep your phone going and available to use for calls and texts with the occasional bit of internet use outside of your home Wi-Fi, GiffGaff is a strong offering. Look out for the T&Cs though as some of the big data deals throttle the speed after a few gig.

Voxi is another one of the brands which benefits from 1-month rolling plans. However, where it differentiates from the rest is in its use of unlimited social media or unlimited video. With these benefits, you don’t use up any data on social media apps or video streaming apps. While the free social media is thrown in on all plans, you usually have to pay more for unlimited video usage.

Virgin Mobile has been going for a long time, and some of its SIM only deals are particularly attractive – especially when it gets going with its brilliant flash sales. It’s one of the providers that offers data rollover, a perk we’re really very fond of.

The UK’s biggest supermarket has been known to offer competitive – if not stellar – SIM plans, with low data prices starting at not much more than a fiver a month. Where it get’s really interesting is if you download the Xtras app to an Android phone: you’ll save £3 on your monthly bill, but you will have to see adverts every time you unlock your handset.

Plusnet might be more well known for its broadband deals these days. but it’s also keen to push some very cheap 30-day SIM only deals. You don’t have to worry about signal either as Plusnet uses EE’s network that covers 99% of the UK. Plusnet’s cheap plans start at around £5 a month.

Sky Mobile:
Sky is one of the many big names which sells phone contracts…and offers SIM plans. Sky specialises in cheaper SIMs, offering low prices on mid-level data plans. It also offers added benefits for existing Sky customers.

Carphone Warehouse:
Carphone Warehouse doesn’t just sell handset contracts. It also has a wide range of SIM only deals for Vodafone, ID and Virgin. The online store is also known to include additional incentives such as half price fees for six months, cashback and the occasional free tech item.

The SIM only deals on this page are checked every day to make sure they’re still available and up to date! If you’re ready to go SIM only, then head back to the top of this page and use our tool to find the perfect plan…

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