It’s not a straightforward answer as it very much depends on where you live as to which providers offer the best mobile coverage. You can use our mobile coverage checker to see which have the best coverage in your area.

Other than that you are going to choose between one of the four providers that actually own their own physical networks:

• Three
• O2
• Vodafone
• EE

All the other providers are virtual mobile networks, they will use one of the above four physical networks to provide coverage for them. These providers include:

• Tesco Mobile
• iD Mobile
• Sky Mobile
• Virgin Mobile
• Voxi
• BT Mobile
• Giffgaff
• Talkmobile
• Asda Mobile
• Smarty
• Lycamobile
• Plusnet Mobile

We don’t think there is any disadvantage in going with one of these providers, they can in many cases actually offer some of the very best prices! 

For Pros we have:

• Price. No phone is part of the deal so all you are paying for is the data and airtime.
• Short contracts. Most contracts are shorter, many rolling 1 month contracts and even the longer contracts can be much shorter than phone contracts, so you aren’t locked in long term.

For Cons we have:

• They don’t come with a phone included, so you’ll have to sort one out for yourself. This is no problem if you have an old phone already or can pick up a second hand one free (or have the cash spare to buy a new phone outright). It’s not great if you want a new phone but can’t afford to buy it outright.

Yes you can get 5G SIM only deals. Many SIM only deals are 5G compatible and will work with 5G wherever it is available.

You obviously need a 5G capable phone to be able to get 5G, if you have an older phone then it might not be 5G enabled, you should check this first.

5G SIM only deals will seamlessly work with 4G in areas where 5G isn’t available.

It’s simple to choose a SIM only deal that suits your need. Just use the comparison table at the top of this page.

• Monthly cost - what’s the most you want to spend per month?
• Network - what networks are you interested in?
• Upfront cost - some deals may have an upfront cost, what’s the most you are willing to pay upfront?
• Data - How much data do you think you will need per month?
• Contract length - what’s the longest contract length that you are interested in?

The comparison table will only show deals that meet the filters you choose. You can sort the results by relevance, monthly cost, upfront cost and total contract cost till you find the deal that works for you.

If you are already on a contract with a mobile network then you’ll have to wait till your contract has finished it’s minimum period. To find if you are still in contract then  just text ‘INFO’ to 85075 on your current phone to find out.

Your current supplier will text you back within a minute with details of if you are still in your minimum contract period or not.

You will obviously also need a phone that’s unlocked so it can accept your new network SIM card (if you are changing networks).

If you want to keep your existing phone number then you will need to get your PAC code from your existing supplier. To get your PAC code, just text ‘PAC’ to 65075 on your handset and your supplier will reply within 1 minute.

We have a full guide on how to switch mobile networks and keep your mobile phone number.

If you are out of contract and have a suitable phone then you just need to choose the SIM only deal that you are interested in, sign up with the supplier online and they will post out your new SIM. 

When your new SIM arrives just slot it into your phone and away you go!

Yes you will need to provide your own phone to slot your new SIM card into.

SIM only deals only provide the SIM card, data and airtime.

The government regulator, Ofcom, introduced the ‘Text to Switch’ regulations which means you don’t have to speak to your current network in order to switch.

All you need to do is text PAC to 65075 and you will get a switching code back in seconds. 

Then all you need to do is give that code to the network you want to switch to and they will take care of the switch and cancelling your account with your old provider for you.

Simple as that!

There’s two methods to see if your phone is unlocked:

1): Try a SIM card from another network in the phone. If it works then your phone is unlocked, if not, it’s locked.

2): Look at your phones settings:

• On an iPhone: 

1): Open the Settings app

2): Select ‘General’ 

3): Select ‘About’

4): Select ‘Carrier Lock’. If it names a network then your phone is locked to that network, if it says ‘No SIM Restrictions’ then your phone is unlocked

• On an Android Phone

1): Open the Settings app

2): Select ‘Connections’ or ‘Network and Internet’

3): Select ‘Mobile Network’

4): Select ‘Choose network’ or ‘Automatically Select Network’. If you are shown only 1 network then your phone is locked, if you see multiple networks then it’s not locked.

All you need to do is text PAC to 65075 and you will get your PAC back in seconds.

How much data you will require will depend upon how you most often use your phone,

If you are out and about most of the day and not connecting to wifi for the majority of your time then you will need more data that if you are based at home or the office most of the time and connecting your phone to wifi.

If you stream a lot of video or audio you will need more data than if you mainly just browse websites.

One word of advice, most people overestimate how much data they will need. You can probably get away with less than you think. Check if your deal allows you to upgrade during your contract, many do, and if you can then try going low to start with and then upgrade if you find you need more.

SIM only contracts are cheaper than phone contracts for the simple reason that you aren’t also covering the cost of buying a phone over the course of the contract.

The main disadvantage of a SIM only deal is that you have to provide your own phone. So unless you have an old phone you already own then you are going to have to pay upfront for a phone from somewhere.

If you are lucky you might find someone, like a family member, who has an old phone spare that they might be willing to loan or give to you. It’s always asking your network of family and friends if they have any spare old phones they no longer want.

SIM only tariffs are cheaper because they don’t supply you with a phone as part of the deal, so they only have to cover the cost of data and airtime which is much less costly than the cost of a phone as well.

With a phone contract you get a new phone, data and airtime as a package. With SIM only there is no phone, just data and airtime, so it’s much cheaper, but you need to supply your own phone.

If you have a phone you are happy with already then it is much better to get a SIM only contract as you’ll have a much cheaper monthly charge.

Why get a phone contract and a new phone if your current phone works fine?

However, if you do fancy a new phone then a contract mobile phone deal is a very cost effective way of getting a new phone if you can’t, or don’t want to, pay for a new phone upfront.

If you are past your minimum contract term you can cancel at any time. 

If you are still within your minimum contract term then there are 3 cases in which you can cancel your contract:

1): In the first 14 days of your contract you can cancel for any reason you like, this is the 14 day cooling off period.

2): If your provider raises their prices by more than the Retail Price Index (RPI) rate of inflation then they must notify you and give you 30 days notice. During this 30 day notice period you are entitled to cancel your contract. 

3): If your contract ends within the next 30 days then you are able to cancel and switch to another provider.

SIM only contracts last from 1 month rolling contracts up to 24 months. The longer term contracts tend to have some of the cheapest prices, but then you are locked in.

Rolling contracts are often more expensive, but you have no long term lock in so are very flexible and a great way of testing out a supplier before committing to a longer term deal.

Yes you can keep your mobile number if you switch to a SIM only deal even if it’s with a new network. You just need to get your PAC code from your current supplier,  text PAC to 65075 and you will get your PAC back in seconds.

To change to SIM only and keep your number just text PAC to 65075 and you will get your PAC back in seconds.

Then when you sign up with a new supplier for a SIM only deal just give them the PAC code you received and they will port your phone number over automatically for you.

Yes, you can buy a SIM card and keep your number provided you get your PAC code from your existing provider and give it to your new provider when you sign up for the new SIM card deal.

If you are staying with the same provider then not a lot will change other than your monthly payments will drop considerably as you are no longer also paying for the cost of the phone.

If you are switching to a new supplier then they will send you a new SIM card that you’ll need to put in your phone to replace the one from your old supplier. Then you can just carry on as before, but with a much cheaper monthly cost!

SIM cards all work to a common standard, so there is no single type of best SIM card.

However, if you are asking which SIM card deal is the best value or best service then this will depend on what you need out of a mobile contract. Use our comparison tool at the top of this page to work out what’s best for your budget and needs.

Most of the mobile networks offer special deals aimed at people (like international students) who need to make a lot of international cards.

We suggest using the comparison tool at the top of this page to browse the latest deals and compare their international call charges.

A money saving tip for international calls, use a third party app like Whatsapp for making calls to people overseas, the call cost is free, you’ll just be using some of your data allowance instead.

Yes you can get SIM only deals that just provide data and no call allowance, this is called SIM only mobile broadband and is perfect for your tablet if it is one of those that can take a SIM and is mobile network compatible.

Yes you can get SIM only mobile broadband deals. They are perfect if you have a device like a router that is 4G or 5G enabled and can take a SIM card.

These deals don’t come with call allowances and just provide a data allowance.

Most SIM only deals, especially the longer contracts, will require a credit check. However, this credit check is much less stringent than that for a phone contract, so even if you have had credit issues in the past you may find that you are much more likely to pass the check for a SIM only deal.

Providing you pay your bills as and when they are due then a SIM only contract can help your credit rating.

Be warned though, if you miss payments then this may well damage your credit rating.

SIM only contracts can include roaming and many do.

Different networks and different deals from the same networks will have different roaming charges and offers. Just make sure to pick one that suits your needs and you will be able to roam whenever you need.

When your SIM only contract ends, that is it comes to the end of its minimum contract period, then it will continue working, you will be charged the same amount each month, you just won’t be tied into the contract anymore.

If you are happy with the service and the price you don’t need to do anything at all.
We’d always suggest you do a price comparison when your contract ends though, as you will usually find you might get a better deal by signing up to a new contract.

A no contract SIM only deal, also known as Pay As You Go (PAYG) is where you don’t sign a contract and you pay upfront for data and airtime. 

When you pay for your first month upfront you’ll be sent a SIM card. When the credit you’ve bought has run out you just pay for more credit and off you go again.

As you are paying upfront for your usage there is no credit check required for pay as you go SIMs.

On short term deals you might find there are no incentives that come with it. On the longer term deals you’ll be much more likely to find incentives.

Just remember that at the end of the day you’ll be paying for the cost of that incentive in your package cost, just ask yourself if you really need that incentive before being lured in by it.

An eSIM is very similar to a SIM card, but instead of being a removable card it’s actually built into your phone.

This means you don’t need to wait for a SIM card to be sent in the post, instead the data can be downloaded straight onto your phone from the internet.

eSIM’s are overwritable so you can switch to a new supplier or contract easily.

Not all phones are eSIM enabled, most new iPhones, Samsungs and Google phones are Dual SIM, which means they can use either a traditional physical SIM card or an eSIM.