Best SIM only deals

What is a SIM only deal?

A SIM only deal gives you a monthly allowance of minutes, texts and mobile data — you’re paying for the SIM and the service rather than a handset.

Should I switch to SIM only? 

SIM only suits you if you’re happy with your current phone or have reached the end of a handset contract. Benefits include:

• Lower monthly cost — you aren’t paying off a handset.
• A wide range of flexible contract lengths (30-day rolling, 12-month, 24-month) keeps pricing competitive.
• Fewer credit checks for SIM-only signups compared with handset contracts — though some rolling plans may still check credit depending on the provider.

How to choose the right SIM only deal

To get the best SIM only deal for you, consider how much data you use, if you're happy with a network that piggybacks off another one, and how much flexibility you need.

📣 Did you know? If you’re switching networks your handset must be unlocked. Ofcom banned the sale of locked handsets from 17 December 2021, so phones bought in the UK after this date are normally sold unlocked.

Pros and cons of SIM only deals

There aren't many downsides to choosing a SIM only deal, but be aware that you must already own a phone.

How to switch and keep your number

If you want to keep your number, you’ll need to get a Porting Authorisation Code (or PAC code). Once you have the code, give it to your new provider to start the switching process - your old contract will be cancelled as the new one is activated.

1. Text PAC to 65075 (valid for 30 days)
2. Give the PAC to your new provider
3. The number port completes next working day if submitted before 5pm
4. For leaving without keeping your number, text STAC to 75075 give this to your new provider to switch and terminate your old service

If you're still in contract, you may be charged early termination fees for leaving. To check how much you'd be charged, text 'INFO' to 85075.

Need more help? Our mobile switching guide will walk you through the process.

Best SIM only deals by need

The cheapest SIM only deals

The cheapest rolling one-month SIM only deals

Which SIM only network is best?

This really depends on what’s most important to you. To help you make the most informed decision, here’s a snapshot of what the four major network providers have to offer:

• Vodafone – Vodafone boasts a decent selection of SIM only plans and pay-as-you-go bundles. You can also opt for an Entertainment plan, which gives you access to your choice between Spotify Premium, YouTube Premium or Amazon Prime
• EE – in terms of coverage, EE is one of the UK’s widest-ranging networks, as well as being the fastest mobile network in general. Some of its more expensive SIM plans come with Inclusive Extras, which gets you a free subscription to the likes of Apple Music, Netflix, BT Sport, among others
• Three – Three is often named as the fastest network for 5G in the UK. All SIMs come with access to Three+ rewards, Three’s customer loyalty app that gets you exclusive offers and pre-sale tickets
• O2 – depending on the SIM plan you pick, O2 offers a host of useful extras, such as a few months’ subscription to Apple Music, plus Disney+, Amazon Prime or Audible. Its O2 Priority rewards scheme is perhaps the best on the market, getting you exclusive deals from shops and restaurants, as well as access to pre-sale tickets. Not to mention, it’s the only major network to still offer inclusive EU roaming

All major network providers offer SIM plans on one-month, 12-month, and 24-month contracts.

Which mobile providers are powered by other networks?

While the four main networks all offer good SIM only deals, smaller providers tend to be more affordable. Known as MVNOs, or mobile virtual network operators, they’re a viable alternative to the household-names.

And what’s more, they all make use of the big providers’ networks, meaning you get much of the same high-quality coverage at a fraction of the price.  

• Sky Mobile - Sky Mobile uses O2's network, so you can expect signal wherever O2 provides it and 5G connectivity. Sky Mobile also let you roll over spare data for later use.
• Smarty - Smarty is owned by Three, it has access to the fastest 5G network in the UK and all its SIM only plans come with 5G support.
• Tesco Mobile - Tesco Mobile uses O2's network, providing 99% 4G coverage in the UK and 5G in many towns and cities. Tesco Mobile have committed to no EU roaming fees until 2026, making them a great option for travellers who want to use their data abroad.
• iD Mobile - Budget network iD Mobile also uses Three, meaning you get snappy 5G access that doesn’t break the bank.
• Giffgaff – Another budget network, Giffgaff uses O2 and has access to its abundance of WiFi hotspots. 
• Lebara - Lebara uses Vodafone’s network, including its 5G and roaming service and 4G calling technology. 
• VOXI - Owned and run by Vodafone, VOXI has cheap deals that include free streaming and social media, preserving your data allowance in the process.
• spusu - spusu SIM only deals are powered by EE's network, come with 5G at no extra cost, and if you're phone is eSIM compatible then you won't need a physical SIM card to get connected.
• Talkmobile - Talkmobile operates on Vodafone's network and provides cheap SIM only deals with free roaming in 47 European countries at no extra cost.
• Asda Mobile - Asda Mobile is another carrier that piggybacks off Vodafone's network, and they offer data rollovers, no mid-contract price rises, and up to 5GB free roaming in 46 different European destinations.

All SIM only networks

Can I trust smaller, less well-known networks? Is the service as good?

Of course – just because a network is less well-known doesn’t mean it’s any less trustworthy than the major network providers.

Customer service tends to be online rather than over the phone, but there’s a wide network of users and staff who can troubleshoot any issues. 

Can I get a 5G SIM only plan?

Yes. Most mobile networks in the UK will offer 5G sim only deals.

Moreover, SIMs will come 5G-ready at no extra cost. As long as your handset is 5G-enabled, you’ll be able to use it straight away.

For a full breakdown, our 5G coverage in the UK guide covers more.

Where is 5G available in the UK?

Networks are constantly expanding their 5G coverage. If you currently live somewhere that doesn't have access to 5G, you may very well get it in the near future.

What SIM card do I need?

There are three sizes of SIM card available:

• Standard SIM card (15mm x 25mm)
• Micro SIM card (12mm x 15mm)
• Nano SIM card (8.8m x 12.3mm)

Each type of SIM card fits different devices. However, standard SIMs and micro SIMs are barely used these days. All smartphones released in the past ten years will use a nano SIM – that’s any iPhone released since the iPhone 5 in 2012, for example.

But don’t worry if you’re not sure what size to go for. Most networks and operators will send a three-in-one SIM card, which lets you pop out the correct SIM size for your device.

It’s worth bearing in mind that some phones feature eSIM. This is an inbuilt chip that allows you to switch providers without having to physically remove your old SIM card and get a new one. 

It makes switching faster, as networks can immediately set to work on getting you set up, cutting down the time it takes to transfer your number. 

You’ll need an iPhone XR or newer (models released since 2018) or Samsung Galaxy S20 or newer (models released since 2020) in order to get one. 

Read more in our eSIM guide. 

Can I cancel my SIM only contract at any time? 

It all depends on the kind of SIM only deal you have. If you have a 30 day, SIM only rolling contract, then yes.   

These plans can be cancelled whenever you like, as you’re only ever paying for 30 days of access at a time. These are usually more expensive than longer plans, but allow for maximum flexibility.  

If you have a 12 or 24 month plan, cancelling it early will be tricky without paying a large fee to cover the cost of the contract.   

If you’re 30 days from the end of your contract or just 14 days in, you can cancel without charge.  

You can also cancel if you have a consistently bad signal, but this is harder to prove.   

Read our guide to cancelling a phone contract for more help.  

More expert SIM only guides

• How to transfer your mobile phone number
• How much mobile data do you need?
• Roaming charges explained
• How to check if your phone is unlocked
• How to check mobile coverage in the UK
• What to do if you're rejected for a phone contract

How do I switch to a SIM only tariff?

Once you've picked a SIM only deal, your next steps are:

1. Get your PAC code (or STAC code if you aren't keeping your number) and give it your new provider.
2. You'll be sent a SIM card (or instructions for activating an eSIM if you've chosen this).
3. As your new plan is activated, your old one will be terminated.
4. Start using your new plan.

If you're still in contract with your current provider, you may be charged exit penalties. To find out if you're still under contract and what fees you'll be subject to, text 'INFO' to 85075.

Can I keep my mobile number if I change to SIM only?

Absolutely – you can keep your mobile number. All you need to do is get a PAC code, which you’ll need to provide to your new network within 30 days.

To get your PAC code, text 'PAC' to 65075.

How can I tell if my phone is unlocked and will accept another network's SIM?

Simply insert a SIM card from a different network and attempt to make a call. If the call connects, the phone is unlocked.

If you don’t have access to a SIM from another network, you should be able to check via the settings of your device. Our guide on how to check if your phone is unlocked explains more.

Can I get a SIM-only deal for a tablet?

If you want to use your tablet while you’re out and not connected to Wi-Fi, you can get a data-only SIM. These work like ordinary SIM cards, but they only come with data, not texts or minutes.Before you buy, check that your tablet has a slot for a SIM card because not all do. Also, check the manufacturer’s handbook to see what type of SIM you need.

What do I do with my old SIM card?

Your SIM card can contain a lot of personal information, including the names and contact numbers of your friends and family. Therefore, to keep yourself safe, the best thing to do is destroy your old SIM card. Cut the chip in half and recycle the plastic shell.

Will there be a credit check for a SIM only deal?

There might be a credit check, but the criteria you have to meet won’t be as stringent as a handset contract deal.