How to get the best deal
There are a number of things you'll want to consider when choosing a SIM only deal. Your first consideration should be your choice of network and provider. There are four networks in the UK – Vodafone, Three, EE and O2 – and all other providers operate on one of these four.
Next, you should consider whether you want a pay monthly or pay as you go (PAYG) SIM, and in the case of pay monthly, whether you are after a rolling 30-day contract or looking to sign up to 12 months or more. Once you have these choices in mind, you can then use our comparison tools (above) to find a SIM deal within your budget and with an amount of data, minutes and texts that suits your needs.
We have a treasure trove of information to help you decide further down this page, but first let's cover the basics.
What is SIM only?
Mobile plans come in a few different flavours. The type most of us are familiar with are pay monthly plans that include a handset. With these type of plans you'll be paying for your services – minutes, data, texts – and on top of that pay monthly instalments for the hire-purchase of your new handset.
SIM only, as the name suggests, is just a SIM, just the services without a handset. You simply put the SIM in your existing handset and, provided your phone isn't locked to another network, off you go. There are short and long pay monthly contracts, or there are pay as you go (PAYG) SIMs which can work out even cheaper to those with minimal usage.
Why choose a SIM only tariff?
- Keep your current handset – New handsets are the single most expensive overhead on a traditional pay monthly with handset deal. Apple now has a phone costing a frankly insane £1,500, but the truth is these flagship phones really don't do all that much that older models don't. Keeping your existing handset is smart, so long as you don't always just have to have the latest thing
- They're cheaper – Because you're not paying for a handset on top of your services, SIM only deals are always much cheaper
- Shorter contracts – Most pay monthly handset deals will tie you in for two years or more so as to cut the considerable cost of the handset into smaller chunks. Deals are 12 months maximum, with a great deal of them on 30-day rolling contract
- Wider choice of networks – All mobile providers offer SIM only, so by taking this route you widen the field of potential new providers
- You may need to unlock your phone – If you got your handset through another provider rather than buying it separately, your phone may be locked to that provider. You therefore may have to unlock your phone before you can install your new SIM. Unlocking your phone is easy, however
- Maybe you want that ultra-high-end handset – If you really want the latest flagship phone from Apple or Samsung, then just buying the handset and SIM outright might not be the best way. Unless you're Richy Rich, that is – in which case fill your boots
How does SIM only work?
There are two types of deal: Pay monthly, which is itself divided into 12-month contracts and one-month (30-day) rolling contracts. And pay as you go, commonly abbreviated to 'PAYG'.
With a pay monthly deal, you will sign up to either a 30-day rolling contract, which you can leave at short notice, or a 12-month contract which you will be tied into for the entire period. Both have the advantage of being able to pay by direct debit. In return for your commitment, 12-month contracts are often cheaper and/or offer more minutes texts and data.
You can pay by direct debit – Whether choosing a 30-day rolling contract or something more long term, a pay monthly SIM is a greater commitment to your provider than a free PAYG SIM, which you can pick up just about anywhere and dispose of whenever you please. For this reason, most pay monthly SIM deals will allow you to pay via direct debit
Your credit won't expire – Pay monthly SIM deals offer a defined amount of minutes, texts and data which will refresh each month. Which is expiry in a way, but only at the exact same moment it's fully topped up. Unless you're frequently exceeding your allowances, this means it's a lot less hassle. If you are doing that, mind you, you're probably on the wrong deal
More of everything for less money – Like it says. Better value, in essence.
Pay as you go (PAYG)
With a pay as you go SIM deal, you'll pay up-front amounts of your choosing, topping up as and when you need to. Keep in mind that most PAYG deals have a fixed expiry on the minutes, texts and data you buy, often as little as 30 days. You cannot, therefore, purchase a tenner's worth of credit and eke it out over several months. There are a few select PAYG deals with a long expiry, so if this is your plan, you should check these out first.
No credit checks – Credit checks for pay montly deals are far less demanding than those involving expensive handsets. That said, if your credit rating won't stand up to any sort of scrutiny right now, a PAYG SIM deal is probably the way to go. No credit checks at all. See our SIM only offers with no credit checks.
Only pay for what you use – If you get your top-ups just right you may find yourself paying for exactly what you use and no more. However, this ideal is rarely achievable in real life, and in terms of value for money, you're always going to be worse off with PAYG
Can be cheaper in some instances – If you manage your credit carefully – and we mean you get it exactly right in terms of the credit you spend during each expiry period – you may just end up paying a little less. We think it's unlikely, though, and PAYG deals should really only be considered by those who are certain they won't pass a credit check
Which contract length is best for me?
Pay monthly deals come in just two flavours: Those on a 30-day rolling contract and those that will tie you in for 12 months. How do you choose between them? Here's how.
30 day contract
- You're passing time till your next handset upgrade – 30-day rolling contract SIMs are great time fillers if you know that a few months down the line you're going to switch again and pick up that handset upgrade you have your eye on
- You're not 100% sure about the provider – Sometimes you'll see an ultra-cheap or appealing deal from a provider you've never been with before, but you're not sure about its coverage, customer service and so on. A 30-day rolling contract can be a good way to try it out
- You can't commit to 12 months – For whatever reason – maybe you're leaving the country – you can't commit to a 12-month contract
12 month contract
- You want the cheapest SIM possible – prices on 12-month contracts are almost always lower than one-month rolling contract deals. For your commitment to the longer term, you get something in return: cheaper prices and/or more minutes, data and texts
Which providers offer SIM only?
Pretty much every provider in the UK offers SIM only. At Cable.co.uk, we don't list every provider because we consider new, unproven and/or minuscule providers with a tiny customer base too risky to recommend. They go out of business all the time. Here are the providers we do stand behind.
- Sky Mobile SIM only – Offers a small-ish range of handset and SIM deals with discounts for Sky broadband and TV customers. Sky Mobile is on the O2 network, and all of its contracts are 12 months
- BT Mobile SIM only – Has deals to suit any need and any budget, and offers some great discounts on its 'Family SIM' deals – where you get additional SIMs for other family members at a reduced price. BT Mobile is on the EE network, and of its SIM contracts are 12 months
- Virgin Mobile SIM only – Low cost and with whopping amounts of data for relatively little money. Virgin Mobile is on the EE network and all of its contracts are 12 months
- EE mobile SIM only – Is the UK's most popular network. As you'd expect, EE will sell you just about anything mobile-related, from SIM only and handset deals to data SIMs for tablets and more. EE is on its own network (naturally), and all its contracts are 12 months long
- Three mobile SIM only – As one of the UK's four network providers, as you'd expect Three offers just about everything. It's on the Three network, of course, and all of its contracts are 12 months long
- Plusnet Mobile SIM only – Plusnet offers some decent deals, but due to the fact that all of its contracts are flexible 30-day affairs you won't get as much for your money as if you're able to commit to another provider for 12 months. Plusnet Mobile is on the EE network
- Tesco Mobile SIM only – The supermarket giant offers 30-day and 12 month contracts. Something for everyone. Tesco operates on the O2 network
- Vodafone mobile SIM only – Vodafone is one of the UK's four network providers. It offer everything under the sun, operating – naturally – on its own network. Vodafone offers both 12-month and 30-day SIM deals
- O2 mobile SIM only – O2 is another of the UK's four network providers. It offers pretty much anything you could possible want, from SIMs to handsets, tablet data SIMs, mobile broadband dongles and more. It operates on its own network and offers both 30-day and 12-month contracts
- giffgaff mobile SIM only – Yes, with a lower-case 'g'. It's a rather unique provider thanks to its community-run customer service. It's owned by O2 and operates on its network. It only offers rolling 30-day contracts on its SIM only deals
- Asda SIM only – Unlike supermarket competitors Tesco, Asda only offers SIM only deals. Some of the cheapest out there, in fact. Asda Mobile operates on the EE network and all of its contracts are rolling 30-day affairs
Types of SIM card – which do you need?
Depending on your handset, you will need one of three different sizes of SIM card. It's a good idea to know which you need before ordering your new SIM.
- Standard – 15mm x 25mm in size, this is the largest of the three. You only generally find standard SIMs in older models of tablet, and some laptops. It's unlikely your phone requires one
- Micro – 12mm x 15mm in size, this is where is gets trickier. Luckily, though, most providers will supply you with what's known as a dual-cut or triple-cut SIM, which encompasses both sizes – you just need to press out the smaller from the larger
- Nano – 8.8mm x 12.3mm in size, most new phones, especially the higher end ones, use a nano SIM. As mentioned above, it's unlikely you'll get the wrong one as most providers these days will send you a dual or triple-cut SIM
Keeping your existing phone number
Switching your mobile provider once your contract has ended is very straight-forward. Of course, you will keep your existing number when switching unless you actually need a new one. Generally speaking, you will follow these steps.
- Request a PAC code – You just need to call your provider, or in some cases you can do this online. They will give you something called a PAC code – stands for porting authorisation code
- Get on your new network – Once you have your new SIM, put it in your phone. You will have a new number at this point, but fret not. Phone your new provider and give them your PAC code
- Wait 48 hours – That's it! Within 48 hours, but often much sooner, your new SIM will be registered with your old phone number
Frequently asked questions
How do I change my SIM card?
It varies from handset to handset. With most new handsets you will find a small hole somewhere around the edge of your phone. Use a pin or the special tool supplied with your phone to press into the hole and pop out the SIM drawer. Take out the old one, put in the new one, close the drawer and Bob's your uncle.
Can I get a SIM only deal for my tablet?
Yes. The big four network providers all provider data SIMs specifically aimed at tablet users.
Can I trust less well-known mobile providers?
Yes and no. While there is generally little wrong with the service you receive from smaller providers, the smaller the provider the less stable it tends to be. New providers come and go all the time, often leaving their customers high and dry. At the very least you should consider a provider that's been around long enough to build a reviewable track record – a few years at least.
Are SIM only deals cheaper?
Yes. Always. If you're getting a handset in the deal, and it's at least a reasonably modern one, you'll be paying for it in instalments on top of your monthly charges for your services. Without a handset you just pay for the services.
Can I get a 4G SIM?
Yes. It's actually hard to find any 3G SIM deals anymore these days. 4G is the norm.
How long does it take to switch?
Around a week. Once you've ordered you'll need to wait (up to 5 working days) to get your new SIM in the post. Once you have it – and in the meantime got your PAC code form your existing provider – it will take another 48 hours to switch the SIM to your old number.
Can I upgrade my deal?
Yes. Once you have the SIM, if you need more minutes, texts or data and you want to upgrade, you can do this with either a phone call to your provider or in many cases, just log into your online account and tick a box or two. You won't need a new SIM and the upgrade is usually instantaneous.