The best SIM only deals in April 2020

So 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 Plusnet and Giffgaff.

What is a SIM only deal?

SIM only deals allow you to just buy the SIM part of a phone contract. That means getting your texts, minutes and data without having to buy the phone as part of the contract. This can then be paired with a SIM-free phone to secure a cheaper deal.

SIM only deals of the week: top 10

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

2. Best 2GB+ data SIMs

3. Best 5GB+ data SIM

4. Best 30-day SIM plan

5. Best big data SIM (20GB+)

6. Cheapest SIM only deal for unlimited data

7.  Best value EE SIM

8. Best cheap Vodafone SIM

10. Best data only SIM deal

SIM only deals FAQ

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.

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 (8.8×12.3mm) 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: can I get 5G plans?

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.

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 by network

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{fb741301fcc9e6a089210a2d6dd4da375f6d1577f4d7524c5633222b81dec1ca} 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. 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

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 – 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.

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{fb741301fcc9e6a089210a2d6dd4da375f6d1577f4d7524c5633222b81dec1ca} 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.

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…