Happy with the phone you've got? Need a SIM to go with it? We've tracked down our pick of the best on offer right now.
What is a SIM only deal
A SIM only deal gets you a monthly allowance of data, calls and texts for a fee. It differs from traditional phone-and-tariff contract in the respect that with SIM only deals, you don’t get a new phone when you sign up.
Instead, you get a SIM and the aforesaid monthly allowances. Which you can use with your existing phone.
SIM only deals are available as flexible one-month, rolling contracts that renew automatically from month to month. But allow you to cancel penalty-free with just 30 days' notice.
Or if you prefer, you can sign up for a 12-month, 18-month or 24-month contract term, which generally gets you better allowances for your money.
Why choose a SIM only deal?
A SIM-only deal is a good bet if you’re happy with the phone you own and aren’t looking to upgrade to a newer model. It’ll allow you to carry on using your phone until you are ready to upgrade.
If you’re buying a phone outright rather than on a contract, you’ll also need a SIM only deal to go with it.
How does a SIM only deal work?
SIM only deals work very much like more familiar phone-and-tariff contracts. Once you’ve chosen a SIM that meets your needs, you'll need to sign up via Compare My Mobile.
The network will then send your SIM through the post, which you put in your phone. And you’re good to go.
If your phone is compatible with E-SIMs, you won’t require a physical SIM.
Once you’ve signed up and your service is live, you’ll be able to activate your plan within the ‘settings’ section of your phone.
Which SIM only network is the best?
Want the network with the best speeds and coverage? Maybe free BT Sport or Amazon Video is more important to you?
Or perhaps a network that lets you roll over unused data is what you're really looking for?
To help you get the network and SIM that best suited to your needs, we've outlined the main networks' key selling points below.
Best EE SIM only deals this week
If speeds and coverage are your main criteria, EE should be top of your list. But as you might expect you'll pay a bit extra for the superior service.
EE incentives aren't the very best around, but still compare well with the competition.
Smart contracts, for instance, allow you to change your customer benefits from month to month, from a selection that includes free BT Sport.
Or you can choose to extend the roaming area in which you can use your UK allowances for no extra charge.
Best Vodafone SIM only deals this week
-
Vodafone sim only
4G- 30GB of 4G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- VeryMe Rewards
- £8.00 per month
12 month contract From Vodafone -
Vodafone sim only
4G- 30GB of 4G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- VeryMe Rewards
- £8.00 per month
12 month contract From Vodafone -
Vodafone sim only
5G- 150GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- VeryMe Rewards
- £25.00 per month
24 month contract From Vodafone
Like EE, Vodafone stands out for good coverage and speeds. But just like EE, its SIMs aren't the cheapest.
The extra outlay can get you welcome customer incentives, though, with select contracts offering a 12-month subscription to your choice of Sky Sports Mobile, Spotify, Amazon Video or Now TV.
Vodafone's other major selling point is an extensive roaming scheme. Depending on the plan you choose, you'll be able to use your UK allowances in 48 or 77 locations for no extra charge.
All customers get free gifts and money-off promotions with Vodafone's VeryMe scheme.
Best Tesco Mobile SIM only deals
-
Tesco Mobile sim only
5G- 2GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free EU Roaming
- £7.50 per month
24 month contract From Tesco Mobile -
Tesco Mobile sim only
5G- 12GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free EU Roaming
- £10.00 per month
24 month contract From Tesco Mobile -
Tesco Mobile sim only
5G- 30GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free EU Roaming
- £12.50 per month
24 month contract From Tesco Mobile
Tesco Mobile's key selling point is that you'll get Clubcard points every time you pay your monthly phone bill. These are paid at a rate of one point for every pound you spend.
It also offers capped contracts, so you can keep tabs on how much you're spending, and inclusive roaming in 31 locations.
Best O2 SIM only deals
-
O2 sim only
5G- 6GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- EU roaming included
- £6.99 per month
12 month contract From O2 -
O2 sim only
5G- 6GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- EU roaming included
- £6.99 per month
12 month contract From O2 -
O2 sim only
5G- 6GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- EU roaming included
- £6.99 per month
12 month contract From O2
O2's award-winning 4G service offers extensive coverage. But its network is generally rated as slower than the likes of EE, Vodafone and Three.
Its customer rewards are very good, however. All plans include O2's Rewards scheme, which gets you money-off promotions and giveaways.
And you get O2 Priority too, which means you're in line for priority booking for events at O2 venues.
O2 also scores highly for its network of 150,000 WiFi hotspots, allowing you to make WiFi calls in areas with a weak signal.
Best Three SIM only deals
-
Three sim only
5G- 3GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Three+ rewards
- £5.00 per month
12 month contract From Three Mobile -
Three sim only
5G- 3GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Three+ rewards
- £5.00 per month
12 month contract From Three Mobile -
Three sim only
5G- 3GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Three+ rewards
- £5.00 per month
12 month contract From Three Mobile
The breadth of Three's roaming scheme is one of the network's main selling points.
Sign up for an Advanced Plan and you'll be able to use your UK allowances in 71 locations. Cheaper Essential plans get you roaming in 48 locations, which is still significantly more than most other networks.
Best iD Mobile SIM only deals
-
ID sim only
5G- 8GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- No annual price rise
- £6.00 per month
1 month contract From iD Mobile -
ID sim only
5G- 8GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- No annual price rise
- £6.00 per month
1 month contract From iD Mobile -
ID sim only
5G- 8GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- No annual price rise
- £6.00 per month
1 month contract From iD Mobile
iD Mobile SIMs stand out for being very keenly priced. You can typically get an iD SIM with enough data for light users for not much more than £5 per month.
iD Mobile's service is based on O2's network. That means that, just like O2, coverage is very good. But while speeds are fine, it's not the fastest network around.
All plans feature inclusive roaming in 50 locations and the option to rollover unused data from month to month.
Best VOXI SIM only deals
-
VOXI sim only
5G- 45GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Unlimited social media
- £10.00 per month
1 month contract From VOXI -
VOXI sim only
5G- 45GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Unlimited social media
- £10.00 per month
1 month contract From VOXI -
VOXI sim only
5G- 105GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Unlimited social media, music & video
- £15.00 per month
1 month contract From VOXI
VOXI's unique selling point is that all customers can use social networking sites as much as they like without eating into their data allowance.
Its roaming scheme, where you can use your UK allowances for no extra charge, takes in 48 locations, and customers can use their monthly allowance for tethering too.
Best BT Mobile SIM only deals
BT Mobile offers existing broadband customers £5 per month discount when they sign up to a SIM only deal. Which makes its SIMs pretty attractive, if that applies to you.
BT Mobile also offers free access to five million WiFi hotspots, as well as inclusive roaming in 47 destinations.
All plans allow you to add more SIMs to save money as part of a family plan. And select BT plans come with free BT Sport, with live coverage of Premier League games, Aviva Premiership Rugby and more.
Best giffgaff SIM only deals
-
GiffGaff sim only
5G- 6GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- £8.00 per month
18 month contract From giffgaff -
GiffGaff sim only
5G- 60GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- £10.00 per month
18 month contract From giffgaff -
GiffGaff sim only
5G- 120GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- £15.00 per month
18 month contract From giffgaff
giffgaff's got a lot to recommend it.
Not least very competitively priced SIMs that get you very attractive allowances for your monthly outlay and good coverage, courtesy of the O2 network on which giffgaff's service is based.
Its no-contract plans are also simple and flexible, allowing you to easily change your allowances from month to month.
However, largely because giffgaff is a cheaper network, it doesn't offer the same sort of perks you get with the likes of O2 and Three.
For instance, inclusive roaming is restricted to the EU on all plans. And there's no conventional customer support either.
If you've got a problem or query, you'll need to head to giffgaff's customer forums, where its community of users field questions and help out.
Best Plusnet Mobile SIM only deals
Plusnet Mobile's service is based on EE's network. So although it's a 'value' network, you'll get very good speeds and coverage.
Unlike BT Mobile, you don't get a discount on a Plusnet Mobile SIM if you're a Plusnet broadband customer. However, you do get extra data, calls and texts.
Plusnet Mobile's Roam Like Home roaming scheme takes in over 40 EU destinations, which is in line with other comparably priced networks.
Pros and cons of SIM only deals
Not sure if a SIM only contract is right for you? Read on as we outline everything that’s good about SIM only deals and everything that’s not so good.
Pros
- They’re cheaper than phone-and-tariff contracts
- You can keep your current phone and carry on using it
- One-month SIMs are flexible and require just 30 days’ notice to cancel
- As long as your phone is unlocked, you can take your pick of all networks
- Networks apply less rigorous checks for SIM only deals than phone contracts
- They’re a good stopgap if you’ve got your eye on a new phone that’s not on sale yet
Cons
- You won’t get a brand new phone
- You may need to pay to get your phone unlocked
What types of SIM only deals are available in 2024?
You can choose from:
- One-month SIMs: These are rolling contract SIM deals, with flexibility as their main selling point
- 12-month, 18-month and 24-month SIMs: These are better value than one-month SIMs, but lock you in for longer.
- Data-only SIMs: Designed for laptops and tablets, these get you a data allowance but don’t include any call minutes or texts.
- E-SIMS: These are electronic SIMs. They work the same as standard, physical SIMs, but make it easier to switch.
Cheap SIM only deals
-
O2 sim only
5G- 30GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- EU roaming included
- £7.99 per month
12 month contract From O2 -
Three sim only
5G- 120GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Three+ rewards
- £12.00 per month
12 month contract From Three Mobile -
VOXI sim only
5G- 105GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Unlimited social media, music & video
- £15.00 per month
1 month contract From VOXI -
GiffGaff sim only
5G- 60GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- £10.00 per month
18 month contract From giffgaff -
Three sim only
5G- 30GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Three+ rewards
- £8.00 per month
24 month contract From Three Mobile -
Lebara Mobile sim only
- Exclusive
- 10GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- EU roaming included
- £5.99 per month
1 month contract From Lebara Mobile
Find the cheapest SIM-only deals by sorting our comparison table by cost. Use the toggle in the top right, and all the lowest-priced SIMs will be shown at the top of the table.
You can also set a maximum price that you'd be willing to pay each month in the sidebar filters, and take a look at everything available in your budget.
For cheap SIM plans, try small networks that specialise in low prices, such as:
- Giffgaff
- iD Mobile
- Plusnet Mobile
- Smarty
- Tesco Mobile
- Virgin Mobile
Unlimited data SIM only deals
-
ID sim only
5G- 40GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Bill capping and data rollover
- £8.00 per month
24 month contract From Mobiles.co.uk -
ID sim only
5G- 80GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Bill capping and data rollover
- £10.00 per month
24 month contract From Mobiles.co.uk -
ID sim only
5G- 150GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Bill capping and data rollover
- £12.00 per month
24 month contract From Mobiles.co.uk
Stream a lot of video on your commute? Download a lot of movies, especially in HD or 4K? Or maybe you play a lot of online games?
If the answer's 'yes', you should seriously consider a SIM with an unlimited download allowance.
Not every network offers unlimited data. But you've got plenty of options, including Three, Vodafone and Smarty.
If the network you'd like to join doesn't offer unlimited data SIMs, you should still be able to get a SIM with a high data allowance that'll get you enough to cover your heavy mobile internet usage.
Best 30-day SIM-only deals
-
VOXI sim only
5G- 105GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Unlimited social media, music & video
- £15.00 per month
1 month contract From VOXI -
ID sim only
5G- 50GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- No annual price rise
- £8.00 per month
12 month contract From iD Mobile -
Lebara Mobile sim only
- Exclusive
- 5GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- EU roaming included
- £4.99 per month
1 month contract From Lebara Mobile -
ID sim only
5G- 50GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- No annual price rise
- £8.00 per month
12 month contract From iD Mobile -
GiffGaff sim only
5G- 60GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- £10.00 per month
18 month contract From giffgaff
It's particularly easy to change your allowance on networks that are technically PAYG, such as Asda Mobile, giffgaff, and Lebara Mobile - take a look at those if you really value flexibility.
Bear in mind that some networks don't extend some customer benefits to one-month plans, so you may not get access to all the same incentives and rewards that you would on a long-term contract.
That's not universal, though - many still let you use things like tethering, extended roaming, and perks like O2 Priority.
What contract lengths are available?
SIM only contracts are on offer that last one month, 12 months, 18 months or 24 months.
The longer term deals generally represent better value for money, but are less flexible and tie in you for at least a year.
How much data do I need in 2024?
Studies by the telecoms regulator Ofcom show that the average Briton gets through around 3GB of data per month.
However, we’re all different. Some of us will use a lot less than that. And some of us will use a lot more.
One of best ways to find out how much data you’ll need is to open up your network provider’s app on your smartphone (assuming you’ve downloaded it, that is), or by logging into your account online.
There, usually in the recent bills section, you’ll be able to see how much data you’ve used for the last months. Then just sign up for a SIM with a comparable amount of data and you’re good to go.
Alternatively, below we’ve compiled a rule-of-thumb guide to help you work what type of user you are. And by extension how much data you’re likely to require.
Light users
- I use the internet on my phone very little -500MB
- I use my phone for email, messaging and occasionally for social media sites -1-2M
Medium users
- I regularly check in on social media, and watch a few videos per month -2-5GB
- I use my phone for work, including email and downloading documents and files -5GB
Heavy users
- I stream lots of music or podcasts daily, and use social media, messaging, and other data-dependent apps too -5-10GB
- I stream video a few times per week -10GB
- I stream lots of video every day -20GB-unlimited
What incentives do SIM only deals have?
That depends on the network you choose. Tesco Mobile SIM customers, for instance, get free Clubcard points every time they pay their bill.
If you’ve got an O2 SIM only deal, you’ll get priority booking at O2 venues and membership of its Rewards scheme.
While Vodafone Entertainment SIMs are bundled with a choice of streaming services, such as YouTube Premium, Amazon Prime or Spotify Premium.
You can get a better, more complete picture of the kind of customer incentives each of the major networks offers in the section labelled ‘Which SIM only network is the best’.
Will there be a credit check for a SIM only deal?
Most SIM only providers will carry out some sort of credit check, especially for longer-term SIM contracts. But they won’t be anything like as stringent as credit checks for phone-and-tariff contracts.
Some networks waive credit checks entirely on one-month SIMs, however. These include Smarty, VOXI, giffgaff and Lebara.
How to find a good value SIM-only deal
Need some guidance to pick SIM deal that fits you? Here are a few things to think about.
Allowance
There's a huge spread on offer here - you can get pretty much any allowance you like.
SIM tariffs range from the tiny (100MB data, plus a few hundred minutes and texts) to the huge (unlimited everything). Check out our guide for more info on working out how much data allowance you need.
Network
You have plenty of networks to choose from for SIM deals too. Some are nice and cheap, others are packed with benefits, and you may even be able to snag a special deal from your current mobile network or broadband / TV provider.
Either way, make sure you check coverage in your area before you commit to a deal.
Contract length
Long-term SIM deals are usually cheaper over the year than one-month SIMs - while short-term deals have the advantage of letting you chop and change your plan whenever you want.
How easy is it to switch networks?
The advent of text to switch has it made easier to change network, removing the need to speak to anyone at your existing network who might try to dissuade you. Assuming you want to keep your number, all you need to do is text the word 'PAC' to your network to get your porting authorisation code (PAC).
Got the PAC? Good news. Now you'll just need to contact the network you'd like to join and give them your PAC. That'll enable them to start the switch. Your number could be transferred to your new network's SIM card next working day.
Can I get a 5G SIM only plan?
Yes, you can. As of May 2020, 5G SIMs are available from BT, Mobile, EE, Vodafone, O2 and Sky Mobile. Three is expected to launch 5G SIMs soon.
However, be mindful that you'll need a 5G compatible phone to use a 5G SIM, such as the OnePlus 8 and the Samsung Galaxy S20 Ultra 5G.
Where is 5G available in the UK?
5G is mostly available in major towns and cities. But its footprint is growing all the time. To help you make your mind up, head to our 5G network page, where we take a good look at each of the UK’s major 5G networks and round up what we consider some of the standout 5G SIM deals on offer right now.
What SIM card do I need?
Most contemporary smartphones use Nano SIMs, which are smaller than the older Micro SIM and Standard SIMs that preceded then. But work just the same way.
However, select phones, such as newer iPhones and Samsung Galaxy S and Galaxy Note models, are compatible with E-SIMs too. These are digital SIM cards that remove the need for a physical SIM.
What is an end of contract notification?
As the name suggests, it's a message sent by your provider to let you know either that your existing contract is about to end, with a view to giving you a heads-up to start looking for a new deal.
Networks have been legally obliged to send these to customers since February 2020. They came into force after millions of customers were found to be overpaying for their existing service, due to networks' habit of dramatically hiking prices once customers' minimum contract terms have expired.
Can I keep my mobile number when I switch to a SIM only deal?
Yes, you can keep your current mobile number if you switch to a SIM on a different network.
In fact, it's easy - there's no reason at all to stick with the same network if you can get a better SIM deal elsewhere.
To get a new deal and keep your number, simply sign up to the deal, then contact your current network for a PAC (porting authorisation code) number.
Once your new SIM arrives and you've activated it, contact your new network and give them the PAC.
Just make sure you do so within 30 days of receiving the code, or it'll expire.
Once the porting is underway, your phone number should transfer over to your new SIM card within a few days.
How do I get my PAC code?
To get the PAC code, you just need to text ‘PAC’ to 65075. Or if you prefer to speak to someone, you can ring up your network and ask for it.
Your network will provide you with a PAC straight away if you asked for it by phone. Or within two hours if you requested it via text message.
Will a SIM only deal improve my credit rating?
Yes, is the short answer. To get a 12-month SIM or longer you'll need to pass a credit check and subsequently pay every month on time. In so doing, you're proving to would-be lenders from whom you may want to borrow in future that you're a good bet for credit.
What do I do with my old SIM card?
SIM cards can contain sensitive information that should be kept out of the wrong hands. For that reason, it’s best to destroy the card.
After removing the card, we recommend you take a pair of scissors and cut the card into thin strips. Then just throw away the pieces.
Can I trust smaller, less well known networks? Is the service as good?
Networks such as giffgaff and iD Mobile might not be as well known as Three, Vodafone or O2. But that's not to say that the service will be worse.
That's because these so-called challenger networks' service is in fact based on infrastructure that's owned and operated by the larger, household-name networks.
That means that giffaff, iD Mobile et al are able to offer the same sort of speeds and coverage as their competitors.
What you may miss out on with less well known networks are freebies and customer incentives that O2, EE and more are able to offer. But given that lesser known networks tend to be cheaper, you may decide that you won't miss them.
What’s the best SIM only deal for an iPhone?
SIM cards from all networks will work in iPhones, as long as you get the right size:
- iPhone 5, 6, 7, 8, 9, X, XS range, XR, 11 range, SE and SE 2 - nano SIM
- iPhone 4 or 4S - micro SIM
- Original iPhone, 3, or 3G - standard SIM
As for allowance, newer iPhone models and Plus versions will probably need a little more data than average, especially if you're upgrading.
It means you'll probably use your phone more, and web pages will load quicker, resulting in more data usage - and viewing video on such a big screen requires a bit more data too.
What’s the best SIM only deal for Samsung Galaxy phones?
As with iPhones, if you want to get the best of your handset you'll need a decent data allowance for a Samsung Galaxy phone.
It'll let you use all your apps, and there's enough data to handle fast processing speeds, high-res video streaming, and uploading quality photos to social media.
Again, you can get a SIM for your Samsung from any network, provided you select the right size SIM card:
- Samsung Galaxy S6, S7, S8, S9, S10, S20 - nano SIM
- Samsung Galaxy S5, S4, S3 - micro SIM
- Samsung Galaxy Note 5, 7, 8, 9 and 10 - nano SIM
- Samsung Galaxy A phones - nano SIM
