The term 'SIM free phone' refers to handsets bought outright and without a contract.
When you buy a phone SIM free, you're solely buying the phone. You don't get the monthly allowance of data, calls and texts that are provided when you buy with the standard phone-and-tariff contracts.
That means that once you've selected your SIM free phone, you'll then have to sign up for a SIM only deal.
As we'll see, there are some major advantages to buying a handset this way. But as we'll also see, it's not for everyone.
More and more people are shunning phone-and-tariff contracts and buying a phone SIM free instead.
So what's behind the trend? In this section, we take a look the key sellings points of sim free phones.
1) It works out cheaper
You can really save money, for one thing. If you do the maths, it actually works out much cheaper to buy a phone SIM free and then get a SIM only deal than it is does to buy a phone on a standard phone-and-tariff contract.
For the sake of example, let's look at some of the iPhone 7 deals available at the time of writing. You could pick up the 32GB model on iD Mobile with monthly allowances of 4GB of data and unlimited texts and calls for £35.99 per month, with £49.99 to pay upfront. That works out to a total outlay of £913.75 over the course of the 24 month contract term.
However, let's suppose you opted to buy the iPhone 7 32GB SIM free for £599. You could then pick up an 12-month iD Mobile SIM with the same monthly allowances of 4GB and unlimited texts and minutes for £9 per month.
Add the £599 outlay to 24 months at £9 per month and your total spend is £815. So that's almost £100 saved over two years.
2) You can switch network whenever you like
SIM free means freedom. Freedom to shop around. And freedom from lengthy contracts.
With standard two-year phone-and-tariff contracts you're tied to your network until you've paid off the phone in full.
Not so with SIM free. Once you've got your phone, you can sign up for a one-month SIM only deal (also known as pay-as-you-go SIM deal) and you're free to change network with just 30 days' notice.
That's handy because if you subsequently see a SIM only deal that's cheaper, you're then free to switch and save yourself some money.
Networks often run limited-time promotions that give you double-data for the same price, for instance. Because you're free to switch with 30 days' notice, you can act quickly and get yourself a really good deal.
3) Going on holiday? Pick a network with inclusive roaming for your destination
Let's suppose you're planning a break to the USA, but it's not covered by your existing network's inclusive roaming scheme.
That means you can either pay for a roaming add-on that does cover that area. Or take your chances and potentially get hit by ruinous roaming charges.
If you bought SIM free and have a one-month/pay as you go SIM only deal, that's not a problem.
You can simply cancel your one-month contract with 30 days' notice. Then sign up for another pay-as-you-go SIM only deal that allows you to use your UK allowances in the US. For example, Three's Feel at Home.
The main disadvantage of buying SIM free is the substantial initial outlay. For example, if you're eyeing a new iPhone or Samsung Galaxy S or Note handset, you'll have to find £600 or so upfront.
Conversely, with standard phone-and-tariff contracts, the cost of the phone is spread over the course of the 24-month contract.
So although you're paying more in the long-term, you don't need to have hundreds of pounds to-hand to get the phone you want.
That's an easy one. Head to our SIM only comparison page and you'll find an extensive choice from all major networks, as well as some lesser known networks that are well worth a look and could save you some cash.
Think you'd like a short-term SIM only deal? Compare pay as you go SIMs.
Looking for a longer-term SIM only deal? Here's where you can compare 12-month contract SIMs.