Whether you require a SIM for a brand new handset 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.
We've searched for and collated the most affordable SIM only plans the UK has to offer and put them in our price comparison above to make it nice and easy for you to narrow down your perfect plan. You can compare offerings on the biggest networks like EE, O2 and Vodafone, as well as budget brands such as iD Mobile, Plusnet and Giffgaff.
We should now probably add Virgin Mobile to those lists. From Black Friday onwards, it has become one of the most competitive networks out there for SIMO deals, and its current 120GB for £20 per month offer is nothing short of sublime (ends January 31). It even means it now competes with Three, whose 30GB for £17 plan is a consistent favourite of ours.
At the other end of the spectrum, Carphone Warehouse-owned iD Mobile is doing a £7 tariff which offers 2.5GB data, 1200 minutes and unlimited texts. We reckon it's the best cheap SIM only deal at the moment, although it gets even cheaper with its £3.99 SIM for 500MB data. And EE is always popular because of its reliable network speeds (and, of course, its Kevin Bacon TV commercials).
Special SIM offer from Virgin Mobile
Virgin Mobile | 12-month contract | 120GB data | Unlimited calls and texts | £20 per month
WOW! Forget going for 12GB, 30GB or even 45GB, because Virgin just dropped a plan that completely destroys the rest. You now get a completely barmy 120GB for a mere £20 per month. It's an absolutely sensational offer, and it beats the rest in terms of value at the moment.
Click to get Virgin's big data mega offer - ends January 31
SIM only deals: what are they?
If you're unsure what we mean by 'SIM only', here's a quick explainer. Going SIMO (to use the common parlance) has become a growing force in the UK mobile industry in the last couple of years, providing a cheap way of running your mobile phone once your contract has run out. They include data, texts and minutes but don't bundle in a new handset. That means SIM deals are far cheaper than standard phone deals and offer immense flexibility to anyone who doesn't want or need a new device.
And considering that millions of Brits overspend on their mobile once they're contract has finished - effectively paying for something they've already paid for - SIM only deals are well worth a look. They can even provide a cost effective alternative to traditional contract plans if you team a new plan with buying a SIM-free phone outright like the iPhone XS.
Our top 10 SIM only deals of the week:
We've run the figures and plucked out the very best tariffs available this month. Whether you’re after the cheapest plan possible, want to dig out the best value big data SIM plan or just want an all-round great deal but don’t know how much to spend, you’ll find a recommendation just for you.
1. The absolute best cheap SIM only deal out there
iD Mobile | 1 month contract | 500MB data | 150 minutes | Unlimited texts | £3.99 per month
This gives the cheapest readily available bills currently available in the UK. If you just need to keep a phone up and running for occasional use, this is the least you can pay. You'd be advised to either keep mobile data switched off or be careful what apps are updating in the background. Or just pay a little extra for more data....
View this SIM deal at iD/Carphone Warehouse
2. Best 1GB data SIM
iD Mobile | 1 month contract | 1GB data | 500 minutes | Unlimited texts | £5 per month
iD is also the best place to get a standard 1GB SIMO. At just £5 per month it's super cheap and you get double the data of the above option for just £1.01 more per month. There's no contract either so you can cancel at any time, and there are a few extra little perks like the ability to roll over unused data to the next month.
3. Best 2GB+ data SIM
Smarty | Monthly contract | 2GB data | Unlimited minutes and texts | £7.50 per month
Smarty is the new kid on the block when it comes to cheap SIMO plans. We like that it offers a rolling 1-month contract meaning you can break free whenever you wish. And the price is very competitive when it comes to the amount of data, calls and texts you get for your money. But the real boon is Smarty's unused credit offer, where you get money back if you use less data than your plan allows each month.
4. Best 9GB+ data SIM
iD Mobile | 1 month contract | 9GB data | 500 minutes | Unlimited texts | £11 per month
9GB is a delightful place to be when it comes to data - you'd be surprised just how much Spotify streaming and Facebook browsing that let's you have. And £11 a month for the privilege is excellent value. The call allowance may look a little restrictive, but iD lets you make calls with your data, so there really is nothing to worry about.
5. Cheapest SIM only deal for unlimited data
Giffgaff | No contract | All-you-can-eat data | Unlimited calls and texts | £25 per month
Netflix marathons, epic Pokemon Go quests, constant Spotify tunes, this all you can eat data bundle is ideal for the serious mobile user who never needs to worry about poxy thing like data allowances or Wi-Fi. A quick word of warning... this tariff may be called 'Always On', but once you've used 20GB of data each month Giffgaff will cut your speed down from 4G. Good to know, especially as the next best unlimited data deal from Three isn't greatly more expensive.
6. Best EE SIM
12-month contract| 60GB data | Unlimited calls and texts | £30 per month + £100 Amazon.co.uk Gift Card
EE can't compare with the other networks and retailers on price alone when it comes to SIMO, but the awesome Amazon.co.uk Gift Card you get with this big data deal means this is the one we'd recommend if you want to jump on to the UK's fastest 4G network. It makes the effective monthly price £21.66, which is excellent for this huge amount of data.
7. Best Three SIM
Three | 12-month contract| 10GB 30GB data | 2500 minutes | Unlimited texts | £17 per month
£17 a month really is a great price when you consider just how much data you're getting. Three remains the undisputed king of the big data SIM deal, and this belter of a tariff proves the point admirably. Alternatively, £3 more a month takes you all the way to 100GB.
8. Best Vodafone SIM
12-month contract | 6GB data | Unlimited calls and texts | £10 per month
Vodafone launched its Basics range of SIMs in 2018 and they're some of the most affordable in the UK. On top of unlimited calls and texts you get a more-than-decent 6GB of monthly data for only a tenner a month. There's no bells and whistles here (overseas roaming isn't included, for example) but the price point is extremely agreeable.
9. Best O2 SIM
12-month contract | 10GB data | Unlimited calls and texts | £17 per month
We'll be straight with you...O2 is rarely among the networks we recommend for SIMO deals. Its prices are generally just too high compared to the bargains that can be had elsewhere. But if your head has been turned by the network's Priority rewards including free coffees and cheap dinners then this 10GB tariff is the best value we've found without resorting to big cashback claiming.
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 other tablet.
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:
- 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.
- 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.
SIM only deals: are they cheaper than phone contracts?
It can be. Teaming a SIM only plan with a standalone SIM-free handset could save you a few quid. It's usually the case when a flagship phone hits the market and contracts are made deliberately expensive. Take the Samsung Galaxy S9 as a prime example, where you could have saved over £100 over two years by splashing the £800-odd for the handset and slipping in a cheap SIM card.
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.
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?
There are three sizes of SIM card that you can get for your phone, and the one you need will depend on your handset. It's been a while since the traditional, so-called standard SIM (15x25mm) has genuinely been the staple in new phones. Instead, any phone you've bought within the last five or so years is much more likely to require a micro (12x15mm) or nano (8.8x12.3mm) SIM - the iPhone 5 was Apple's first mobile with a nano SIM, while Samsung began using the smallest size in its Galaxy S6.
Before you purchase your new SIM, double-check the manufacturer's website to see what size you require. And if you're simply not sure, most networks now simply send out a triple SIM, so you'll get one of each size.
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 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.
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?
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: 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
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
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
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. And it has has just started getting generous with perks - you can get cheap dinners and free coffees through its Wuntu app. See our pick of the best deals at Three
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.
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.
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.
SIM only deals: Virgin Mobile
Virgin Mobile has been going for a long time, and some of its SIM only deals are particularly attractive. They're all one-month rolling contracts, so you can stop paying at any time if you so wish, giving you flexibility if you want to change your plan or go for a phone-inclusive deal down the line.
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.
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.
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.
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...