SIM Only deals

A SIM only deal is perfect if you already have a phone you're happy to carry on using, or if you'd rather just pay for a handset outright without a long-term contract attached.

SIM only deals are usually much less expensive per month than a handset + SIM plan, so you’ll be paying much lower monthly fees over the length of your contract.

Compare our best SIM only deals today to find the perfect plan for your personal mobile phone needs.

When you decide on a SIM only deal, you can click through to the network or retailer’s website to purchase it. Here’s how it goes:

If you're upgrading your contract with your current provider, it should be really straightforward to switch to a new deal and keep your number. But if you've found the deal via a third party, like Uswitch or another price comparison website, you'll need to check with your network that it can switch you over.

The latest coverage figures from Opensignal* for the big four networks are: 

To find out what coverage you can get where you are, put your postcode into Ofcom’s coverage checker.

That means Three’s network covers more UK locations than any other provider. SMARTY and iD Mobile also operate on the Three network, so they’ll offer the same coverage.

Here's a look at how every network operates:

SIM only deals often give you great plans with plenty of data, minutes and texts for a fraction of the price of a contract plan.

They're great value for money, they're flexible, they can include lots of data and much more.

There aren't many downsides, with the only main downside being that they don't come with a mobile phone included in the deal, so you will need a handset of your own to use the SIM card.

Several factors will come into play when choosing the right SIM only deal for your needs. You should consider the length of your deal, how much you want to spend, your monthly data allowance and whether you’re interested in additional perks or prefer a no-frills bundle.

You can currently get a SIM only deal for as little as £1.58, which comes with 1GB of data. It’s not a huge amount but it’s certainly enough for many UK consumers. You don’t have to pay a lot more to increase your data, either. This iD Mobile deal offers 70GB for just £10 a month. And there are plenty of similar deals, too. 

While SIM only deals can change, it’s an indication of how much you can save, compared to a pay-monthly mobile phone contract. 

According to Ofcom, the average mobile phone user in 2022 used about 5.6GB per month while connected to mobile data on their smartphone. That covers browsing the web, checking emails and scrolling through social media. 

So you may think you need unlimited data, but in reality, a much smaller package would be more than enough. The less data you need, the more money you can save, as smaller bundles are usually cheaper than big data plans.

If you want to see how much data you're using, all you have to do is take a look at your network's app on your phone. There, you should find a detailed breakdown of exactly how much data you use on a monthly basis.

The length of contract you choose comes down to your personal preference. You can usually choose from:  

If you want to switch networks to find a better deal, you first need to find out how long is left on your existing contract. However, if you’re unsure how long you’re locked in for, contact your network or text INFO to 85075. 

If you’re still on a mobile phone contract, you’ll have to wait for the plan to end before you switch over to SIM only, unless you’re willing to pay a cancellation fee. 

When you're approaching the end of your contract, your network is now obliged to send you an end-of-contract notification.

Once you're out of contract, switching networks is as simple as sending a text, thanks to the introduction of the text-to-switch legislation.

Moving networks is usually a near-seamless process so you're hardly ever out of service.

You'll still be able to take calls and receive texts after you've given your new network your PAC code.

When the actual switch to your new network happens, you may lose service for a very short period of time.

When the transfer is done, just put your new SIM into your phone and switch it on. If the phone works and you can make calls, you've got service and you're all set.

Your new SIM only contract will usually start when your SIM card has been dispatched. If it’s a physical SIM card, just pop it in your smartphone and you’ll be good to go. If it’s an eSIM, you’ll need to follow your network’s set-up instructions, but it will usually be a straightforward procedure of activating the eSIM in your phone’s settings. 

As of December 2021, networks aren’t allowed to sell locked phones, so if you got your phone after this date, it should already be unlocked.

A locked phone can only be used on the network you bought it on, but this can differ depending on which network, handset and plan you have. However, there's a simple way to see if your phone is unlocked.

If you’re on an iPhone, go to Settings > General > About and scroll down until you see Network Provider Lock. Your phone will be unlocked if it says, ‘No SIM restrictions’. But if there’s a network’s name there, it is locked. 

If you use an Android device, the method is very similar. Go to: Settings > Connections > Network and internet > Mobile network > Choose network. If you can now see several networks, your phone is unlocked. But if only one is showing, your phone is locked to that provider.

Check out our guide to unlocking your mobile phone for more details. 

Once you’ve confirmed that your phone is unlocked, you're now free to get a new SIM. The next thing to do is find a SIM only deal that suits your needs.

We offer deals from most major UK mobile networks. You can compare SIM only contracts from Vodafone, O2, Smarty, VOXI, Three, giffgaff and more.

Although the likes of giffgaff and VOXI aren't as instantly recognisable as high-street names, such as Three and O2, they're certainly brands you can trust. That's because their service is based on larger providers' network infrastructure, which these smaller networks pay a fee to use.

For instance, VOXI operates through Vodafone. So despite having a different name, different plans and different prices, VOXI’s coverage, speed and quality will be the same as Vodafone. 

In fact, many smaller networks offer market-leading call rates and data deals, so they can often work out cheaper than more well-known networks.

However, the larger networks tend to offer more in the way of benefits and customer support.

To keep prices low, some smaller networks don't operate a call centre and offer online support only. With a big-name network, you’ll usually always be able to speak to a person if you need help with your account. 

And don’t think benefits like O2 Priority Tickets and Vodafone’s VeryMe app are reserved for the major providers. Smaller networks offer incentives too, like VOXI’s data-free social media, iD's data rollover and Tesco Mobile’s Clubcard points 

For more information on each network’s perks and features, check out our dedicated network pages: 

Want to know which network is doing the most for its customers? 

Each year, we highlight mobile networks in our Uswitch Awards, recognising the best in the market customer service, coverage, roaming and more.

Determined by consumer research as well as the decisions of a panel of judges, comprised of technology journalists and industry experts, these awards represent a seal of quality.

Take a look at the 2023 winners to see how the networks did in a selection of different categories.

Here at Uswitch, we’ve been helping consumers lower their household bills since 2000. As we became one of the UK’s top home services comparison sites, we’ve helped people switch to cheaper SIM only, mobiles, broadband and insurance deals, saving consumers over £2.5 billion off their bills in the process. 

If you still have some questions, help is at hand, Take a look at our mobile phone guides, where we cover the big topics in-depth: 

How to transfer your mobile number to a new phone: In this guide, we help you switch to your new provider.

How much mobile data do you need? Read our guide on internet data allowances.

How to switch mobile networks: Switching mobile phone providers can seem daunting, but this guide makes it easier: find out more about how to switch your mobile network.

Can I use my mobile phone abroad? Take a deep dive into every UK network’s current roaming policy. 

Which mobile network offers the best perks? From freebies to early-access tickets, there are all sorts of perks on offer when you sign up for a new mobile phone deal. 

*Opensignal data report from September 2022