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The best SIM only deals in December 2020

SIM only deals are a great option for many people in the UK and one that has rapidly become more popular. As people begin to hold onto phones for longer, the value of SIM plans has become obvious.

Whether you've got the cash to buy a SIM-free phone, you've got a contract that's ended or you've picked up a cheap second-hand phone somewhere, investing in SIM only deals is a great way to keep the costs low.

And the great news is that there is a load of choice out there. While the obvious choices remain with EE, Vodafone, Three and O2, there are now a host of smaller names known as MVNOs offering unique selling points.

Voxi for example can give you unlimited use of social media, many operate on 1-month rolling contracts allowing you to leave at any time, some come with reward schemes and others are just really cheap.

In fact, the main issue with SIM only deals these days is trying to work through all the many options to work out which one is best for your current needs and luckily, we've made that process a bit easier.

In these guide, we've picked out the top 10 SIM plans and answered all of the obvious queries you might have.

Three | 12-month contract | All-you-can-eat data | Unlimited calls and texts | £16 per month
While Three already had the best price around for unlimited data, it has taken it a step further, bringing the price all the way down to just £16 a month. That is exceptional and by the looks of things, the best price we are going to get over Black Friday this year.
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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 plans
  • EE: best for fast speeds and overall performance
  • Vodafone: strong balance of affordability and features
  • O2: heavy on the added benefits
  • Smarty Mobile: best value 1-month rolling option
  • Voxi: best for social media users 

SIM only deals of the week: top 10

1. The best cheap SIM plan

SIM only plan from Lebara | 1-month contract | 2GB data | 1000 minutes and texts | £2.50 for six months
This plan stands out as the cheapest SIM plan we've seen this Black Friday - an impressive feat considering the mass of discounts. For just £2.50 a month, you're getting 2GB of data - perfect for those who don't use much each month. After six months, the pricing will go back up to £5 a month.

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2. Best 5GB+ data SIM

iD SIM | 1 month contract | 12GB data | Unlimited minutes and texts | £8 per month
This offer from iD Mobile is absolutely fantastic, offering 12GB of data for just £8 a month. That keeps your bills low while allowing you to access plenty of streaming, gaming and social media as well as other data intensive activities. At this price, you won't be able to get more data than this.
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3. Best 30-day SIM plan

Smarty SIM | 1 month rolling | 30GB data | Unlimited calls and texts | £10 per month
Smarty just keeps going all out on affordable SIMs! With this plan, you're paying just £10 a month to get 30GB of data. That's an excellent price to be paying, especially when you consider the fact that Smarty operates on 1-month rolling contracts meaning you can leave at any time.
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4. Best big data SIM (20GB+)

Smarty SIM | 1 month rolling | 50GB data | Unlimited calls and texts | £12 per month
Smarty recently slashed the costs of this package, meaning you now have to pay just £12 a month for 50GB of data. That's an excellent price for that much data and one that isn't rivalled by many. With 50GB of data you'll be able to stream, game and use your phone on the internet all the way through the month with no concerns.
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5. Cheapest unlimited data SIM only deal

Three SIM | 12-month contract | All-you-can-eat data | Unlimited calls and texts | £16 per month
Three has introduced its Black Friday deals already, offering the UK's cheapest 5G unlimited data SIM. You're now paying just £16 a month for no caps on your data, calls or texts. That's an exceptional price and one we can't imagine getting beaten over the duration of Black Friday.View Deal

SIM only plan from iD Mobile | 12 month contract |Unlimited data, calls and texts | £15 per month + £30 Amazon voucher
For £1 less each month, iD Mobile can get you the same unlimited data SIM. It also comes with a £30 Amazon voucher. However, unlike Three it isn't 5G loaded and doesn't come with additional bonuses like travel features. This is the option to go if you're looking to keep bills low.
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6.  Best EE SIM plan

EE | 24-month contract | 200GB data | Unlimited calls & texts | 5G ready | FREE Beats Flex Earphones | £25/pm
200GB is a heck of a lot of data, and most people's usage will easily be under that. The free Beats earphones are a cracking freebie, and you'll also be able to bag one plan with either BT Sport, Apple Music, Prime Video and more. If you're fine with a 24-month plan, it's a great deal.
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7. Best Vodafone SIM plan

Vodafone SIM | 12-month contract | 100GB data| Unlimited texts and calls | £16 per month + £54 cashback by redemption
This deal on Vodafone gets you 100GB of data while only charging £16 a month for it. While that alone is an excellent offer, it gets even better. Vodafone is also throwing in £54 in cashback, effectively bringing the costs you're paying down to just £11 a month - a market-leading plan.
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8. Best O2 SIM only deal + free Disney Plus

O2 | 12-month contract | 150GB data | Unlimited calls and texts | £20 per month + 12 month Disney+ subscription
This O2 contract goes all in on your data cap, supplying you with an extremely impressive 150GB of data. That's the kind of cap reserved for people who do everything possible to power through data. Playing high intensity games, streaming in HD on the go and tethering over devices. On top of the data cap, that £20 a month cost also gets you Disney+ for a whole year!
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9. Best SIM for social media users

Voxi SIM | 12-month contract | 12GB data | Unlimited calls and texts | £12 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 £12 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 £12 a month deal.

sim card

Should you get a SIM plan?

There is a couple of situations where you should consider a SIM plan, all of which are based around saving money. The first is if you're considering investing in a SIM-free phone and need something to pair with it.

This is almost always the cheapest way to get a phone, allowing you to undercut the costs of a contract as long as you have the money upfront to spend.

The other situation you might find yourself in is that your phone contract has come to an end but you want to hold onto the device. In this situation, you can simply invest in a new SIM plan and replace it. 

In both of these events, SIM only deals could be the perfect solution.

pound sign

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?

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.

sim cards

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 (8.8x12.3mm)

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

(Image credit: Sky Mobile)

Can I get 5G SIM only deals?

Yes, you can! As part of the 5G movement, a number of networks have started offering the possibility of getting enhanced speeds and latency with 5G SIM only deals. Right now both Vodafone and Three offer 5G and 4G on all of its plans, it simply depends on whether your phone is compatible.

There are a number of 5G compatible phones out there (you can see the top ones with our 5G phone deals guide).

As for EE, you will have to pay more to get your 5G SIMs, with a premium added cost involved.

sim only contract

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.

GB logo

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.

text messages

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:

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.

SIM only deals by network

EE SIM only deals:
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.

Head straight to EE to see all of its best SIMs

O2 SIM only deals:
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.

Go to O2's website to find out more

Vodafone SIM only deals:
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.

Go straight to Vodafone to compare all of the deals

Three SIM only deals:
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.

Head to Three to see all of its plans.

iD Mobile SIM only deals:
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.

Compare all of iD's SIM plans

Smarty Mobile SIM only deals:
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.

Check out the full range of Smarty SIMs

BT SIM only deals:
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.

Go straight to BT's website to see all of the available SIMs

GiffGaff SIM only deals:
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.

You can go straight to GiffGaff to see all of the deals

Virgin SIM only deals:
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.

See Virgin's full list of SIM packages

Tesco SIM only deals:
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.

See Tesco's full collection of SIM deals

Plusnet SIM only deals:
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.

See Plusnet's full range of SIM only deals

Carphone Warehouse SIM only deals:
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.

Head over to Carphone to see its full range of SIM plans

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...