Compare SIM Only Deals: The UK’s Best Mobile Phone SIM Cards

SIM-only deals can save you money on your mobile phone bill every month. Compare the UK’s best value SIM-only deals.

A good way to save money on your phone bill is by switching to a SIM-only deal. This is a low-cost SIM card for your mobile phone with an inclusive allowance of minutes, texts and mobile data. You can keep your current phone number when changing to a SIM-only deal and will normally get lots of flexibility with either a 12-month or a 1-month rolling contract.

In this article, we’ll review and compare the UK’s best value SIM-only deals. This includes big name mobile networks like EE, O2, Three and Vodafone as well as lower-cost alternatives like giffgaff, iD Mobile, SMARTY and VOXI.

How Do SIM Only Deals Work?

A SIM only deal for your mobile phone gives you an allowance of minutes, texts and mobile data. You’ll get a new SIM card that slots into your smartphone, normally with much lower prices than what you’d pay on a normal mobile contract.

Here are some key things to know about SIM Only deals:

1. You’ll Keep Your Existing Phone Number

When switching to a SIM-only deal, it’s easy taking your phone number with you. Simply request a PAC Code from your old mobile network, either through their app, website or text message. You can then provide this code to your new network. Our PAC Code Finder can walk you through this process one step at a time.

2. The New SIM Card Slots Into Your Smartphone

When you sign up for a SIM-only deal, you’ll be sent a SIM card through the post from your new mobile network. This SIM card will slot inside your current smartphone. There’s no need to backup or to transfer any data: your phone book, photos, messages and other apps will still be there after you change your SIM card.

If your mobile phone was previously used on another mobile network, it might be necessary for you to unlock it. For more information, see our step-by-step guides to unlocking an iPhone and unlocking a Samsung Galaxy smartphone.

3. You’ll Always Get Coverage From EE, O2, Three or Vodafone

Regardless of which mobile network you choose, you’ll always be getting coverage from one of the four big providers.

Other mobile networks piggyback on coverage from the big four:

• Networks using EE coverage include ASDA Mobile, BT Mobile, Plusnet Mobile and Virgin Mobile.
• Networks using O2 coverage include giffgaff, Sky Mobile and Tesco Mobile.
• Networks using Three coverage include iD Mobile and SMARTY.
• Networks using Vodafone coverage include Lebara Mobile, Talkmobile and VOXI.

4. You’ll Save Money Compared To A Regular Contract

A SIM-only deal will usually work out to be much cheaper than a traditional 24-month contract. For instance, you might need to pay around £50/month for the latest iPhone on a 24-month contract with 4GB of data. The equivalent SIM-only deal would cost you around £8/month, saving you in the region of £500 per year.

Nowadays, many people decide to buy their mobile phones on a SIM-free basis and use it in conjunction with a SIM-only deal. This usually saves you a fair bit of money and gives you a lot more flexibility compared to a 24-month contract.

Compare SIM Only Deals

The following interactive comparison tool can help you to find the best value SIM card for your usage.

Simply choose how much data you want on your SIM-only deal, the maximum contract length you’d be happy with and the mobile networks you’re considering:

You can scroll through the full list of price plans to see currently available deals that match your criteria. If you’re not sure about how much data you’d like on your plan, see our guide to mobile download limits.

Best SIM Only Networks By Feature

Best SIM Card For Value

The best value SIM-only deal really depends on how much data you need each month. It’s important not to get carried away and to choose a plan with lots more data than you actually need.

Once you’ve decided how much data you need, the following table will show you a summary of the cheapest SIM-only mobile networks with at least that amount of data:

Data Allowance	Cheapest Plan	Cheapest Mobile Network
500MB Data	£5.00/month	Smarty & Lebara Mobile
1GB Data	£5.00/month	Smarty & Lebara Mobile
2GB Data	£5.00/month	Smarty & Lebara Mobile
3GB Data	£5.00/month	Smarty
4GB Data	£6.00/month	Three & iD Mobile
6GB Data	£7.00/month	Smarty & iD Mobile
8GB Data	£7.00/month	Smarty
12GB Data	£8.00/month	iD Mobile & Three
20GB Data	£10.00/month	Smarty & iD Mobile
100GB Data	£15.00/month	Three & iD Mobile

Alternatively, use the interactive comparison table above, selecting the amount of data you need. It will show you a list of available price plans that match your criteria.

Best SIM Card For Network Coverage

If you’re looking for the SIM-only mobile network that gives you the best coverage, there isn’t a simple answer to this as it depends very much on where you live.

All four network coverage providers claim to offer 99% population coverage, but they differ in the exact areas they cover and in the strength and type of mobile signal.

The easiest way to check the coverage in your area is by clicking through to the relevant online coverage maps for each provider:

• Check EE coverage
• Check O2 coverage
• Check Three coverage
• Check Vodafone coverage

Enter your postcode on each of the above coverage maps to see whether you’re able to get coverage where you live. Alternatively, you can read our in-depth guides to the coverage on EE, O2, Three and Vodafone.

Once you’ve figured out the coverage providers that work in your area, find out which mobile networks piggyback on each provider. Piggyback mobile networks offer the same underlying coverage as the host mobile network provider.

• Networks using EE coverage include ASDA Mobile, BT Mobile, Plusnet Mobile and Virgin Mobile.
• Networks using O2 coverage include giffgaff, Sky Mobile and Tesco Mobile.
• Networks using Three coverage include iD Mobile and SMARTY.
• Networks using Vodafone coverage include Lebara Mobile, Talkmobile and VOXI.

Our interactive comparison table above will allow you to filter SIM-only deals by the coverage provider they’re using.

Best SIM Card For Flexibility & No Credit Check

If you’re looking for a flexible SIM card that doesn’t require credit checks, you can choose a SIM-only deal from ASDA Mobile, giffgaff, Lebara Mobile, SMARTY or VOXI. All of them offer one-month rolling plans that you pay for in advance, with no credit check required.

At present, you can get 2GB of data from £5/month on a flexible SIM-only deal:

Network	Minutes	Texts	Data	Monthly Cost
	Unlimited	Unlimited	3GB	£5.00
	1,000	1,000	2GB	£5.00
	Unlimited	Unlimited	3GB	£8.00
	Unlimited	Unlimited	6GB	£10.00

Because of the flexibility that’s available to you, it’s possible to change the plan you buy as frequently as every month (e.g. to get more data or to save money by changing to a plan with less data).

For more information, read our guide to SIM-only deals with no need for a credit check.

Best SIM Card For Download Speeds

For access to the fastest download speeds, pick a SIM card that gives you access to 5G coverage on a 5G-ready smartphone.

At present, you can get a 5G SIM-only deal for as little as £5/month, with plans available from multiple different networks.

The following table shows the cheapest 5G-ready SIM-only deals available on each network:

Network	Minutes	Texts	Data	Monthly Cost
	200	Unlimited	2GB	£5.00 12 months
	Unlimited	Unlimited	4GB	£6.00 12 months
	Unlimited	Unlimited	10GB	£8.00 12 months
	5,000	5,000	12GB	£10.00 18 months
	Unlimited	Unlimited	9GB	£10.00 1 month
	Unlimited	Unlimited	1GB	£10.00 24 months
	Unlimited	Unlimited	12GB	£12.00 1 month
	Unlimited	Unlimited	5GB	£15.00 24 months
	Unlimited	Unlimited	160GB	£20.00 24 months

Our guide to 5G SIM-only deals has a full comparison of the options available on each network.

Best SIM Card For International Roaming

On most SIM-only deals, you’ll have access to international roaming. This allows you to continue using your smartphone when abroad in other countries. There are some notable exceptions to this, such as on Vodafone’s discounted Basics price plan which offers UK-only usage.

If you regularly travel abroad to other countries, we’d recommend getting a SIM card from Three. This is because their SIM-only price plans include the Go Roam offer which allows you to use your mobile phone in 71 destinations at no extra charge. This includes most European countries along with 20 destinations outside of Europe (including the USA, Australia, New Zealand and more).

Network	Minutes	Texts	Data	Monthly Cost
	Unlimited	Unlimited	12GB	£8.00 12 months
	Unlimited	Unlimited	30GB	£12.00 12 months
	Unlimited	Unlimited	100GB	£15.00 12 months
	Unlimited	Unlimited	Unlimited	£16.00 12 months

You can also choose Vodafone’s Unlimited Max price plan which comes with roaming at no extra cost in 81 destinations through Global Roaming Plus. Alternatively, EE offers the Roam Further Pass as a swappable benefit on their Smart SIM cards allowing you to use your mobile phone in the USA, Canada, Mexico, Australia and New Zealand.

Best SIM Card For Unlimited Data

An unlimited data plan will allow you to use your mobile phone as much as you like without needing to worry about running out of data mid-month.

If you’re looking for a SIM-only deal with unlimited data, you can currently choose from ten different mobile networks.

The following table shows a selection of the cheapest unlimited data plans available on each network:

Network	Minutes	Texts	Data	Monthly Cost
	Unlimited	Unlimited	Unlimited	£16.00 12 months
	Unlimited	Unlimited	Unlimited	£16.00 12 months
	Unlimited	Unlimited	Unlimited	£17.00 1 month
	Unlimited	Unlimited	Unlimited	£20.00 24 months
	Unlimited	Unlimited	Unlimited 2Mbps max	£22.00 24 months
	Unlimited	Unlimited	Always-On	£25.00 1 month
	Unlimited	Unlimited	Unlimited	£25.00 1 month
	Unlimited	Unlimited	Unlimited 10Mbps max	£26.00 24 months
	Unlimited	Unlimited	Unlimited	£30.00 24 months
	Unlimited	Unlimited	Unlimited	£30.00 18 months
	Unlimited	Unlimited	Unlimited	£35.00 1 month
	Unlimited	Unlimited	Unlimited	£37.00 24 months

For more information, see our full round-up of unlimited data plans in the UK. As an alternative, you can also consider a zero-rated data plan which gives you unlimited data for use on certain services (e.g. for social media, video or music).

More Information

For further information about a specific SIM-only deal, please click through to the relevant website to learn more about it. Alternatively, you can read our in-depth reviews of mobile networks and tariffs in the UK.