Best SIM only deals: save money on mobile deals

If you don’t want a new phone, SIM only deals are ideal as they give you flexibility. You don’t have to be tied down to one single mobile phone provider for months or years.

Plus, the last thing you want is to be locked into a lengthy mobile contract. In such situations, finding the best SIM only deals with flexible contracts could be just the ticket. 

In this guide, we explain everything you need to know about SIM only deals, and our top picks currently available in the market. We update this weekly so that you make the best savings without losing out on valuable talk time with friends and family. 

If you’re ready to start looking for a new contract, compare SIM only deals on our comparison.

The best SIM only deals

Cheapest SIM only deal

Lyca mobile SIM only

Lyca SIM only | 3GB data | £0.99 per month | One-month contract | Unlimited minutes and texts

Lyca Mobile is offering you 3GB of mobile data for 99p per month. After three months, you will pay £4.4 per month, although you can cancel your contract before the price goes up. You get unlimited minutes and texts and 50 international minutes in the EU, USA and China. On top of that, you get EU roaming as well. 

Cheapest 20GB SIM deal

Lyca mobile SIM only

Lyca SIM Only | 20GB data | £2.39 per month | One-month contract | Unlimited minutes and texts

New Lyca customers can get 20GB of mobile data for just £2.39 a month. After three months, your monthly bill goes up to £7.9. But you’ll be on a one-month contract, so you can cancel anytime, with 30 days’ notice. You also get unlimited minutes and texts in the UK, and 100 international minutes to the EU, USA and China. 

Best deal for 50GB

iD Mobile SIM only | 50GB data | £8 per month | One-month contract | Unlimited minutes and texts | Plus redeem up to three months free Apple TV Plus, Music and Arcade

iD Mobile is offering 50GB of data for £8 per month on a one-month contract. It includes unlimited minutes and texts and 5G at no extra cost. You can use your UK data allowance up to 30GB in 50 locations around the world. Plus, you can roll over any unused data and cap your monthly spend. On top of that, you can redeem up to three months of free Apple TV Plus, Music and Arcade. 

Cheapest SIM deal for 100GB+

Talkmobile SIM only | 120GB data | £11.95 per month | One-month contract | Unlimited minutes and texts

This Talkmobile SIM only deal offers a generous 120GB of mobile data for £11.95 per month. It runs on Vodafone’s network which means that you’ll get 99.9% population coverage. This SIM only deal comes with unlimited minutes and texts, plus you can keep your old number if you’d like. 

Best SIM only deal for unlimited data


SMARTY Mobile SIM only | Unlimited data | £16 per month | One-month contract | Unlimited minutes and texts

SMARTY’s SIM only deal offers unlimited mobile data for £16 a month. This deal includes unlimited minutes and texts, no speed caps and unrestricted tethering in the UK at no extra cost. Plus, you get free Wi-Fi calling and EU roaming subject to a 12GB per month fair use limit. SMARTY runs on Three’s network. 

What is a SIM only deal?

Unlimited data SIM only contracts

With a SIM only deal, you only get a SIM card and no handset. SIM stands for ‘Subscriber Identity Module’. It’s basically the small bit of plastic that slots into the back of your phone. The SIM allows you to connect to your network so you can make calls and send text messages. 

SIMs also hold all the information you need on them, such as emails and contacts. These are transferable, so you can move yours over to another handset at any point if you want to. This is provided it isn’t locked to another network. 

How does a SIM only deal work?

Here are the two main types of SIM only deals:

  • Pay monthly: You’ll sign up for a rolling 30-day contract and get an allowance for calls, texts and data to use each month. If you want to end the contract at any time, simply give a one-month notice. Some SIM only deals allow you to commit to a 12-month contract if you’re comfortable being tied in for a longer period.
  • Pay as you go: These require you to top up your phone with credit as and when you need it, so you’re not tied into a contract at all.

Here’s what you do to get the SIM to work:

Simply insert it into your telephone, following the instructions you will have been provided with. Then you should be good to go.  

Why get a SIM only deal?

The biggest advantage of a SIM only deal is that they are much cheaper than other mobile deals. This is because you’re not paying for a handset. The only cost is for the data, texts and minutes you’ll use. 

Another benefit is that SIM only deals are more flexible than other types of mobile deals. You won’t be locked into a lengthy contract. So if you want to switch providers, you’ll usually only have to give 30 days’ notice. 

SIM only need-to-knows

SIM only deals

Here’s an at-a-glance guide to some of the essentials you need to know about SIM only deals.

A SIM card is essentially a computer chip that is used to store information such as your contacts, emails, photos and messages. It enables you to connect to your network provider so you can make calls and send texts and so on. Without a SIM you wouldn’t be able to use your phone.

The amount of data you’ll need from your SIM only deal depends on how you use your phone. For example, if you stream regularly, you’ll need more data than someone who just sends texts and make calls. Check previous bills to see how much data you tend to use each month. As a general rule, most people typically use up to around 3GB a month.

SIM only deals typically run on a 30-day rolling contract, providing you with flexibility if you decide you want to switch to a different network. However, it is usually possible to sign up for a 12-month contract if you want to. 

If you have a SIM only deal, then it’s only the SIM that is locked to the network and not the phone handset itself. A locked phone is a handset that will only accept a SIM card from a particular network. From December 2021, mobile companies will be banned from selling phones which only work with their network.

How to switch SIM only deals

If you want to move to a different SIM only deal, you’ll need to wait until your current contract finishes. Most contracts only run for 30 days so you shouldn’t have to wait long.

Want to keep the same number when you move? You’ll need to request a PAC code (Porting Authorisation Code) from your existing provider. This can be done by texting PAC to 65075.

When you’ve got your PAC code, you’ll need to get in touch with the provider you’re joining. Give them the code so they can then arrange the switch on your behalf.

How to unlock a smartphone

If you want to unlock a smartphone that’s locked to a particular network, contact the network provider and give them your IMEI number. This essentially identifies your phone.

You can find this in Settings > About’ or ‘About device’ in your iPhone or Android.

Different networks have different approaches to unlocking phones. So you’ll need to check with them how long the process will take and whether there are any costs involved. 

SIM networks and piggybacking

Even though there are only four main networks (Vodafone, EE, Three and O2) several other providers piggyback on their signals, often offering competitive deals.

This means that even if you can only get good coverage in your area from one particular provider, you should still be able to pick from a wide choice of deals when you include piggyback providers.

These providers include SMARTY (Three), giffgaff and Tesco Mobile (O2), Plusnet and BT Mobile (EE) and Voxi (Vodafone).