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The best SIM only deals in September 2020

SIM only deals are an option rapidly increasing in popularity. They allow you to buy an allowance of data, calls and texts all for one simple monthly charge. This allows you to buy a phone separately or use it in an existing device you have.

For thousands of people in the UK, SIM only deals have represented a cheap and more flexible alternative. Not only are there more options when it comes to contract lengths but pricing is also far more flexible with plans starting from less than a fiver a month.

But it’s not just the cheap plans that stand out. The likes of Three continually offer massive data plans at affordable price points, Smarty, Voxi and iD Mobile keep things flexible with 1-month rolling plans and EE continues to offer super speedy 4G SIMs.

In other words, there are a lot of SIM only deals out there fitting a variety of needs and if you already know what you’re looking for, the comparison chart above will let you filter for data, price, network and more.

Three | 12-month contract | All-you-can-eat data | Unlimited calls and texts | £18 per month
Three is offering the best SIM plan on the market by a long way. Here you're getting unlimited calls, texts and data, all for just £18 a month. That puts it a couple of quid a month below the average unlimited plan.View Deal

For those that are new to the world of SIM plans and have no idea where to start, you’re in the right place. Further down the page, you can find our top ten favourite plans, answers to common questions, the benefits of certain networks and more.

So whether you require a SIM for brand new phones or are trying to eke out an extra few months of your beloved old mobile, our guide to the best SIM only deals is your passport to the lowest possible monthly phone bills.

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

We've looked through all of the available retailers and networks to bring you the absolute top 10 options. This includes all of the available options from EE, O2, Three, Vodafone, iD, Smarty and more.

1. Best cheap SIM plan

Lebara SIM only | 1 month contract | 2GB data | 1000 minutes and texts | £5 per month
Lebara is one of the cheapest providers of SIM plans out there and thrives best at low prices. This deal for example provides you with 2GB of data for just £5 a month. That is a price that can only really be matched by iD Mobile.

Score 2GB of data at a low price with Lebara

2. Best 5GB+ data SIM

iD Mobile | 1 month contract | 9GB data | Unlimited minutes and texts | £9 per month
iD Mobile is a brand synonymous with affordability and this plan supports that well. For £9 a month, iD can supply you with 9GB of data. That's plenty for most people's casual streaming needs, supplying enough to catch up with a bit of Netflix streaming, some social media and plenty of Google searches each month.

Check out this excellent value iD SIMO

3. Best 30-day SIM plan

Smarty | 1 month rolling | 30GB data | Unlimited calls and texts | £10 per month
Smarty's really got this affordability thing down! Go with Smarty and you'll end up paying just £10 each month for 30GB of data. While that is obviously a great price for that amount of data, the factor that really makes Smarty shine is the 1-month rolling contracts it operates on.

Get this amazing SIMO price from Smarty

4. Best big data SIM (20GB+)

Smarty | 1 month rolling | 100GB data | Unlimited calls and texts | £15 per month
Smarty has a number of affordable plans but this is the best. It is currently offering double the data, securing you 100GB each month but it only charges you £15. On top of the high data cap and low costs, Smarty operates on 1-month rolling contracts so you can stay for as long as you like or leave at any time.

Head through to Smarty to get this limited time offer

5. Cheapest SIM only deal for unlimited data

iD Mobile | 1-month rolling contract | All-you-can-eat data | Unlimited calls and texts | £18 per month
When it comes to unlimited data SIM only deals, iD Mobile has stepped in with an absolute bargain. It operates on a 1-month rolling contract while only costing you £18 a month. That puts this at the same cost as Three but takes the contract down to 30 dats at the time.

View this reduced all-you-can-eat deal at iD Mobile

6.  Best value EE SIM

24 months | 100GB data | Unlimited calls and texts | £20
Has EE finally got competitive with its pricing...with this deal, it looks like it has. For the price of £20 a month, you're getting a massive 100GB of data. While that is already pretty affordable, it gets better considering EE will charge you half the amount for the first three months of your contract.

Get the best value EE SIMO deal out there

7. Best cheap Vodafone SIM

12-month contract | 8GB data| Unlimited texts and calls | £8 per month
This offer from Vodafone is great. For the price of £8 a month, you're getting 8GB of data. That makes it one of the cheapest plans around on any network, especially for this much data. However, this is a Vodafone basics package so you won't get Veryme or roaming in other countries.

Click here to get this great value Basics SIM from Vodafone

8. Best O2 SIM only deal + free Disney Plus

O2 | 12-month contract | 80GB data | Unlimited calls and texts | £20 per month + Disney Plus for six months
O2 has really stepped up its game of late and of all of its latest options, this one is the standout. Offering 80GB of data for just £20 a month. Alongside the data package, O2 will also throw in a free six month subscription to Disney Plus.

Check out O2's big data + Disney Plus subscription deal

9. Best SIM for social media users

Voxi | 12-month contract | 12GB data | Unlimited calls and texts | £10 per month + free social media usage
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.

Check out Voxi's cheap SIM deal with free social media

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.

View this deal at Three.co.uk

SIM only deals FAQ

sim card

SIM only deals: should you get one?

If you a) want to save some money; b) don't want to be tied into a lengthy contract; or c) both of the above, then SIM only is well worth considering. In fact, you're probably one of two people if your thoughts are indeed turning to SIM only:

  1. You're coming to the end of your contract and your network is calling you a million times a day to get you to upgrade. Well if your phone is dying a death or you just fancy a change, head to our best mobile phones deal page to see what bargains are lurking, but otherwise going SIM only on your current phone is a no-brainer. You'll wind up paying much less than you are under contract, and you can stick to a rolling 30 day contract so that if your circumstances change, you can get out of the arrangement tout suite.

  2. It's time for a shiny new smartphone and you want to get the best value humanly possible. You'll have to find a few hundred quid up front for the handset (be sure to check our SIM free price comparison tool) but box clever and you'll end up paying less over the next 24 months (see below). Plus, if you're a commitment-phobe, most SIM-only plans don't require you to sign up for two years like you would with a normal contract.

pound sign

SIM only deals: are they cheaper than phone contracts?

It can be. Teaming a SIM only plan with a SIM-free phone could save you a few quid. 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.

unlocked mobile phones

SIM only deals: 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 exception, alas, is Apple iPhones. They're generally sold locked to the original network that you purchase them with for the life of the handset. Very frustrating if you're looking for a tasty SIM deal once your 24 month sentence is up.

The good news is that your iPhone (or any other mobile before the end of your contract) can be unlocked - 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.
  • O2 As long as you don't own an iPhone X, 8, 8 Plus, Samsung Galaxy S8 or S8 Plus (they can't be unlocked until you've paid off your contract), you can unlock any O2 phone - including iPhones - for free if you're on a pay monthly contract. PAYG customers have to pay £15.
  • 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 only deals: What SIM card size do I need?

sim cards

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.

SIM only deals: can I get 5G plans?

(Image credit: Sky Mobile)

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 your SIM. 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.

telephone numbers

SIM only deals: 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. If you're on one of the major networks, you can see what phone number you can contact them on here:

  • EE 07953 966 250
  • O2 0344 8090202
  • Vodafone 03333 040 191
  • Three 0333 300 3333
  • ID 0333 003 7777
  • GiffGaff 43431 from your handset
  • Virgin 0345 6000 789
  • BT 0800 800 150
  • Tesco 0345 301 4455
  • Sky 03300 412 524
  • Asda 0800 079 2732

If you want to grab a bargain SIM only plan above, but it's on your existing network then your network won't release a PAC code and you'll be forced to take a new phone number.

At least you would have, if it wasn't for this clever (if convoluted) work-around. You have to order a free pay-as-you-go SIM from another network. Once you have it, you can tell your old network that you're moving and they'll give you that precious PAC code. Then, once your number is registered to the substitute network, simply get another PAC code from them. Take that to your old network, and they'll move your number to your new contract. Simple - kind of!

sim only contract

SIM only deals: What contract length should I get?

Unlike with a contract, there's a lot more flexibility available when it comes to how long your SIM only plan will last. Two year commitments are virtually unheard of, with the norm being either one year or rolling one month contracts for ultimate flexibility. You can often get better prices if you tie yourself in for 12 months, especially on larger data tariffs. But sticking to one month at a time means that you can effectively hand pick a new plan to suit you every 30 days or so.

GB logo

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.

text messages

SIM only deals: Do I need unlimited calls and texts?

Call it practicality, call it greediness, call it what you want - it's human nature to want 'unlimited' anything if offered. But you should think genuinely about whether you really need it in a world where the likes of WhatsApp and Skype let you call and text for free over wi-fi or 4G. If you decide that a few thousand monthly minutes and texts should do you, then you could shave off some cash from your bill.

SIM only deals: What's the best mobile network?

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.

SIM only deals: 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.

SIM only deals by network

ee sim only

SIM only deals: EE

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. See our pick of the best deals at EE

o2 sim only

SIM only deals: O2

O2's best claim for your contract is with its Priority rewards - from cheap lunch deals and pre-order privileges on gig tickets, to ad-hoc discounts and competitions. Plus, they have 1000s of Wi-Fi hotspots in shops and cafes that you can connect to for free and save your precious data. See our pick of the best deals at O2

vodafone sim only

SIM only deals: Vodafone

Vodafone seems to have been around since mobile phones were cumbersome bricks, but they remain a major player. Look out for a Red Entertainment tariff, which gives you your choice of a NOW TV Entertainment Pass, Spotify Premium or Sky Sports Mobile subscription. See our pick of the best deals at Vodafone

three sim only

SIM only deals: Three

Three is still the only network to offer unlimited data and it often features unbeatable deals on other big data plans - that makes them a natural choice of many a data hungry smartphone addict. It did used to have a rewards app called Wuntu but it has now pulled that out, meaning you'll have to say goodbye to free coffees and competitions. See our pick of the best deals at Three

(Image credit: BT)

SIM only deals: BT

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.

ID mobile

SIM only deals: iD

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.

giffgaff

SIM only deals: GiffGaff

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.

virgin sim only

SIM only deals: Virgin Mobile

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.

tesco sim only

SIM only deals: Tesco Mobile

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 sim only

SIM only deals: Plusnet

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.

carphone warehouse

SIM only deals: Carphone Warehouse

Carphone Warehouse doesn't just sell handset contracts. It also has a wide range of SIM only deals for Vodafone, O2, EE and ID. The online store is also known to include additional incentives such as half price fees for six months, free Beats by Dre headphones or Currys vouchers - so check out what's available right now.

(Image credit: Fonehouse)

SIM only deals: Fonehouse

While Fonehouse may not be quite as recognisable as some of the retailers above, it has a huge range of excellent SIM only deals. Whether you need something on EE, Three or Vodafone, Fonehouse is a name to keep in mind for cheap SIM only deals.

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...