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SIM Only deals

Keep your mobile phone, switch to SIM Only, and you could save £321* a year. Compare our best SIM Only deals today

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Author Ray Ali Last updated 31 August 2023

Everything you need to know about 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.

What happens when I choose a SIM only deal?

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:

  • Sign up to your SIM only plan - Confirm all the deal terms and submit your details if you need to complete a credit check.

  • Get your PAC code. This is the code you need to keep your current phone number. Check the steps below to find out what to do. 

  • Get your SIM - Hooray! Once everything’s confirmed, you’ll get your new SIM.

  • Start using your SIM – All you need to do is pop your new SIM in your phone and you’ll be ready to go. 

Can I move to a SIM only deal with my current network?

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.

Which network has the best coverage?

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

  • Three: 98.5%

  • EE: 97.7%

  • O2: 96.2%

  • Vodafone: 96.6%

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:

MVNOWhich network is it based on?
Asda MobileVodafone
BT MobileEE
iD MobileThree
Lebara MobileVodafone
Lyca MobileEE
Sky MobileO2
Tesco MobileO2

Why should I choose a SIM only deal and what are the benefits?

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.

  • Monthly mobile phone payments have risen by £9.50 since April price rise

  • You could save up to £335 a year by moving to a SIM only deal

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.

Pros and cons

  • Flexible data bundles

  • You can keep your current phone

  • Choose a deal from 14 networks

  • Short-term contracts so less financial commitment

  • Cheaper than a pay monthly deal

  • You don’t get a mobile phone with the deal

How do I find the best deal for me?

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.

Our featured SIM only deal

SIM detailsLebara Mobile SIM card
Monthly price£6.95 p/m
Data allowance15GB
Contract lengthNo contract
ExtrasEU roaming included

How much should I pay?

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. 

Select the right amount of data

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.

Pick your preferred contract length

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

  • 30-day deals: These short-term plans are perfect for people who want a no-commitment SIM deal. You can keep the plan rolling for as long as you like, but you can also cancel and switch to a new plan at any point after the initial 30 days. You’re more likely to get a cheap 30-day deal on a smaller network like Lebara, giffgaff or SMARTY.

  • 12-month deals: Opt for this type of deal and you’ll be committed to using it for a year. After that, you can keep using it or switch over to a new plan at any time. 

  • 18/24-month deals: This is ideal if you just want to sign up for a SIM only deal you’re happy with and not worry about finding a new one anytime soon. Longer deals are common with larger networks like Vodafone and O2. 

How easy is it to switch networks?

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.

Will I lose service if I switch to another network?

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.

When will my new SIM only contract start?

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. 

Will I need to unlock my phone to use it with a new SIM only deal?

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.

Which network should I join? 

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: 

Uswitch Awards 2023 winners

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.

Best SIM only networksWinnerHighly commended
Network of the YeargiffgaffTesco Mobile
Fastest Mobile Network - Powered by OpenSignalEEVodafone
Best SIM only NetworkBTTesco Mobile
Best Network for Customer ServiceTesco MobileEE
Best Network for DataEEVodafone
Best Network for RoamingO2giffgaff
Most Popular Mobile NetworkO2Three
Best Pay Monthly NetworkTesco MobileEE
Best PAYG NetworkgiffgaffTesco Mobile

Guides to help you switch

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.