What is a SIM only plan?

A SIM card is a small chip which slots into your phone, allowing you to make calls and connect to the internet. A SIM only plan will include an allowance of data, calls and texts for a monthly cost. Unlike traditional pay monthly contracts, these plans do not include a phone, meaning all you only pay for is the SIM card and its allowances.

Is SIM only right for me?

If you’re out of contract and happy with your existing phone, a SIM only plan is a great way to save money on your mobile bill.

If you bought your phone on a pay-monthly contract, check if your contract has ended (these usually last 1 or 2 years). Some networks will continue to charge you at the same rate even though you’ve paid off the cost of your phone. Switching to a SIM only plan as soon as your contract expires will ensure you don’t pay too much.

Or, perhaps you have your eye on a new phone, and can afford to buy it outright (SIM-free)? This will cost you more upfront, but can often save you money over the length of the contract.

Does SIM card size matter?

There are three common sizes of SIM card: standard, micro and nano (the smallest). Most newest phones use a nano SIM. When you sign up to SIM only plan, you’ll usually be sent a SIM card with cut-outs for standard, micro and nano sizes so you don't need to worry about ordering the wrong size for your smartphone.

How much data should I look for in a SIM only deal?

This is one of the most important questions when choosing a SIM only plan. The amount of data you need will depend on how much you use your phone, what you use your phone for, and how often you are connected to WiFi.

If you only use your phone for things like email, web browsing, and checking social media, chances are that you’ll only need 3 -- 4GB (this is what the average person uses in the UK). Remember, your data allowance is only used up when you’re not connected to WiFi.

However, if you’re often streaming video or music on the go, you’re likely to need more data.

To check your usage, all you need to do is check your phone. Most phones will show you a breakdown of how much data you’ve used over the course of the month.

What if I run out of data?

In most cases, if you exceed your data allowance you will no longer be able connect to the internet and use messaging apps. Your network provider will often send you text message when you’re nearing your limit so that you’re not left unexpectedly disconnected.

Most operators will offer you the option of topping up your data, for a cost, until your monthly allowance is reset.

Is it easy to switch to another network?

If signed up for a pay-monthly contract, first check if it has ended. Your network will send you an end of contract notification when you approach the end of your contract.

Once you are out of contract, switching to a different network is simple. You no longer have to phone your current provider to switch, avoiding the potential hard sell of it trying to make you stay.

To switch and keep your existing number, simply text 'PAC' to 65075 and you'll be sent a special code, called a PAC (Porting Authorisation Code). To get a new number, text 'STAC' to 75075. You will need to give this code to your new provider within 30 days, and you'll be switched within one working day.