The definitive guide to SIM only

Submitted by Abi on 10 February 2015 - 3:22pm

What is a SIM-only contract?

SIM-only contracts work in the same way as traditional mobile phone contracts except for one distinct factor; you provide the mobile phone. This means all you pay for is a monthly bundle of call, text and data allowances. Without the cost of a phone included, contracts can start from as little as £5 a month. 

SIM-only plans aren't new but they have grown in popularity over the last few years. This is due to the outstanding value they offer and because of a lack of recent advancements in mobile phone technology means more of us are choosing to keep hold of our phones for longer. You still get many of the same network benefits and extras as phone contract customers, including things like O2's Priority and Three's Feel at Home roaming.

What are the benefits of SIM-only?

Aside from value for money the other big advantage to SIM only deals is the contract length. The maximum contract duration is just 12 months, half the length of a traditional mobile phone contract. However if it's flexibility you want then for an additional £2 - £3 a month you can choose a 30-day deal instead.

What will I receive from my network?

When you join a network all you'll receive is your SIM card. This slots into your phone and connects you to your chosen network so you can acess and use your call, text and data allowances.

If you're not sure which SIM size is right for your phone check out our guide Which SIM Card Do I Need?, before you place your order. Each phone is different so if you're unsure where to locate your phone's SIM slot take a look at our guide How to find your SIM card

Do I need to unlock my phone?

Probably. If you bought your phone from your network then it is likely to be locked to that network so you will need to unlock it before you can use your new network's SIM card. This is easy to do and many networks offer this service free of charge, though some do charge up to £20. Visit our guide How to unlock your mobile phone for more advice.

Can I keep my mobile phone number?

Yes. All networks will let you transfer your number to a new network or keep your number if you are upgrading to a new deal directly with the same network - note this is not always the case if you buy through third party resellers such as Carphone Warehouse. Read our guide How to port your mobile telephone number for more advice.

What are the disadvantages of SIM-only?

The big drawback to SIM-only is that you don't get a new phone with your contract. However, it's worth bearing in mind that other than a few extras megapixels in your camera and a larger screen smartphones haven't changed much in the last couple of years. If you're happy with your phone then join the thousands of smart consumers who are saving themselves hundreds of pounds a year by keeping hold of their mobile for a while longer. 

If you don’t already own a phone you can pick up a very basic model from as little as £10. For newer smartphone models you can find some second hand deals online but if you want a brand new phone you can actually save money by buying your phone SIM-free.

Why you should choose SIM-only

Now you know what a SIM-only contract is, but is it really for you? To help you decide we've included some of reasons why you should choose SIM-only.

SIM-only is cheaper than Pay-As-You-Go 

Pay As You Go is only cost effective if you’re a very infrequent user. For example, if you use any more than 100 minutes and 100 texts a month you’ll save money on a SIM only contract.

You don't need to pass the same credit rating tests

Being approved for a mobile phone contract can be difficult if you have a poor credit rating, especially if you want a newer high-end phone. SIM only deals tend to have lower requirements for credit scores so you're much more likely to be accepted. An added bonus is that your regular monthly bill payments will actually help to build your credit rating making it easier fo you to get accepted for phone contracts in the future.

You can keep your phone or upgrade when you want to

Whether you want to keep your exisitng phone and save money with a 12 month plan, or you want the flexibility to upgrade when it suits you with a 30-day deal, SIM-only gives you the freedom to do what you want. 

Although some networks let you just pay the airtime (allowances) part of your plan once you've paid off the cost of your phone, it can still be much cheaper to buy your phone outright. Not only could this save you hundreds of pounds across the life of your contract, but because you're buying a SIM-free phone you can move to a different network when you want to. 

You can try out a new network without a big commitment

The shorter contracts available on SIM-only offer a really useful way to try out services before you commit. Whether you want to test a network’s coverage in your area or you’re new to mobile contracts and are unsure how much talk, text and data allowance you really need, a 30-day SIM lets you try before you buy.

Short term contracts that don't tie you down

The flexibility of 30-day plans makes them ideal if you need a short term contract to bridge the gap while you wait for a particular new phone to be released. Or, if you are a parent looking for a deal for your kids, networks like giffgaff offer peace of mind with 30-day deals that don’t let you spend outside of your plan.

Now you're a SIM-only expert, find your perfect deal with our guide Choosing the best SIM-only deal for you.