A SIM-only plan is exactly what it says on the tin: it’s a mobile deal that gives you just a SIM card but not a handset. It’s ideal when you’re happy with the mobile phone you already have, or if you prefer to buy a phone outright from a retailer.
It works exactly the same as any other pay-monthly mobile plan: each month you’ll get a tariff of data, texts, and calling minutes for a set cost, although it’s usually cheaper per month than a handset contract.
You can also get pay-as-you-go SIM-only deals, where you buy credit for your SIM that you can use for calls, texts, and mobile data.
When you’ve bought your phone separately, or already own it, a SIM-only plan really is the way to go. There are all kinds of benefits:
Yes, you can keep your phone number when you change to a SIM-only deal, even if you’re switching networks. To do this, contact your current network when you want to cancel and request a PAC code. This won’t cost you anything, and they must issue it to you within two working days.
Once you’ve received your code, you’ll have 30 days to give it to your new network. They’ll then get to work transferring the number - which usually takes a working day or so.
1. Make sure you’re free to switch networks. If you have a brand new mobile, you can probably get a SIM from any network you want; but if you’re using your old phone, you’ll have to check. Some networks lock mobiles so you can only get a SIM from that network.
2. Figure out what SIM you need. Work out what size your phone requires - standard, micro, or nano - and roughly what allowance you want.
3. Compare your options using our price comparison tool above, and pick a deal you like the look of.
4. Contact your existing network, and tell them you want to cancel your current plan and switch networks. If you want to keep your existing number, you’ll need to ask for a PAC code too. And if your phone is locked to the network, you’ll need to ask for it to be unlocked, which may cost you a small fee.
5. You’re ready to get your new deal. Click through to the provider’s website and sign up - and give them your PAC if you’ve got one.
There are four kinds of SIM card:
To find out which size your phone needs, see the one currently in use, refer to your user manual, or look on the manufacturer’s website.
The iPhone 4 takes a micro SIM; anything beyond that (iPhone 5 and above) uses a nano SIM. You can use any SIM-only plan you like in an iPhone, so long as the card itself is the right size.
You can get a SIM-only deal from the following networks:
Most of the less well-known networks are mobile virtual network operators (or MVNOs for short), meaning they use the infrastructure of bigger networks. For example, Talkmobile is an MVNO that uses the Vodafone network, and giffgaff is an MVNO that uses O2.
Generally speaking, smaller networks offer good value, cheap SIM-only deals without all the fuss. They have the same coverage as the larger networks, but are able to offer lower prices due to their lower overhead costs. They tend not to advertise as much, they don't have to maintain the physical network, and they're less likely to give you the freebies and benefits you get from a big network.
A huge advantage of going SIM-only is that you can get a 30-day plan, with no long-term contract to worry about. These only run for one month - as opposed to 12 or 24 months - and roll over to the next month until you decide to cancel it. This means you have a whole lot more freedom over your plan, and can cancel it and get a better one whenever you like.
You can currently get no-contract SIM-only deals from: Asda Mobile, EE, FreedomPop, iD, LIFE Mobile, O2, Talkmobile, TalkTalk Mobile, Tesco Mobile, Three, TPO Mobile, Virgin Mobile, and Vodafone.
To browse and compare 30-day SIM deals, just select 'one month contract' in the filters above.
Unlike a phone contract plan, you may not need a credit check to get a SIM-only deal. You can get SIM-only deals without a credit check from these networks:
You can use your SIM for mobile tethering on plans from these networks: Asda Mobile, EE, FreedomPop, EE, giffgaff, O2, TalkTalk Mobile, Tesco Mobile, Three, Vodafone.
Some will only let you tether on pay-monthly plans; some have a cap on how much data you can tether; and some require you to buy a special add-on. Be sure to read the terms and conditions in full before you commit.
Read our guide to tethering for more information and a detailed breakdown of how you can tether on each network.
A lot of networks offer unique SIMs for sticking in your iPad or tablet. These have a data allowance, but no minutes or texts, since you can’t use those on a tablet. To find a good SIM-only deal for your tablet, select the amount of data you want, and look for plans that are data-only.
We recommend choosing a 4G deal for this, as you’ll get much faster and more reliable internet - perfect for browsing and using apps.