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. Discover and compare the 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 you’ll normally get lots of flexibility with either a 12-month or a 1-month rolling contract.

In this article, we’ll review SIM Only deals in the UK 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 be given a new SIM card that slots into your smartphone and will be billed for your usage of the SIM card each month.

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 possible to take your current phone number with you. This is a fairly straightforward process and only involves you requesting a PAC Code from your old mobile 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 simply slot inside your current smartphone. There’s no need to backup or transfer any data: your phone book, photos, messages and other data will still be there on your phone after you do this.

If your mobile phone was previously used on a different 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 EE, O2, Three or Vodafone Coverage

Regardless of which mobile network you choose, you’ll always be getting coverage from one of the big four (that’s EE, O2, Three and Vodafone).

Other mobile networks simply 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 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 mobile phone contract. For instance, you might need to pay more than £50/month for the latest iPhone on a 24-month contract with 4GB of data. The equivalent SIM-only deal would cost you around £10/month, giving a saving of about £500 per year.

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

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 unsure about how much data you want on your plan, see our guide to mobile download limits. As of 2019, the average smartphone user consumes about 2GB of data per month in the UK.

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 more expensive plan with lots of data that you don’t 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:

Data Allowance	Cheapest Plan	Cheapest Mobile Network
500MB Data	£5.00/month	iD Mobile & Lebara Mobile
1GB Data	£5.00/month	iD Mobile & Lebara Mobile
2GB Data	£7.00/month	Plusnet Mobile & iD Mobile
3GB Data	£8.00/month	Vodafone & Plusnet Mobile
4GB Data	£9.00/month	Three
8GB Data	£9.00/month	Three
12GB Data	£13.00/month	Three
20GB Data	£15.00/month	VOXI
100GB Data	£18.00/month	Three

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:

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Enter your postcode on each of the above coverage maps to see whether you’re able to get network coverage from EE, O2, Three and Vodafone.

Once you’ve figured out the coverage providers that work in your area, it’s then worth being aware of which mobile networks piggyback on each provider. Piggyback mobile networks offer the same level of coverage as the mobile network they use.

• 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 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 £7/month on a flexible SIM-only deal:

Network	Minutes	Texts	Internet	Monthly Cost
	300	Unlimited	2GB	£7.00
	Unlimited	Unlimited	2GB	£7.50
	500	Unlimited	2GB	£8.00
	Unlimited	Unlimited	8GB	£10.00
	Unlimited	Unlimited	4GB	£10.00

Because of the flexibility that’s available on the plans, you can 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).

The lowest prices are currently available on ASDA Mobile which uses coverage from EE, but there are also options that use coverage from O2 (giffgaff), Three (SMARTY) and Vodafone (Lebara Mobile and VOXI).

Best SIM Card For Download Speeds

In the UK, the fastest download speeds are currently available on EE’s 5G Smart SIMs. As long as you have a 5G-ready smartphone and as long as you live in a 5G coverage area, you’ll be able to get super-fast 5G download speeds. You’ll also get two Swappable Benefits included with your SIM card:

Network	Minutes	Texts	Internet	Monthly Cost
	Unlimited	Unlimited	Unlimited	£44.00 12 months

Other mobile networks are due to launch a 5G service later in 2019. Vodafone will launch their 5G service on the 3rd July 2019 with Three launching their 5G service in August 2019. O2 is still yet to announce their 5G launch date, but it is expected before the end of 2019.

If you have a 4G smartphone, the fastest download speeds also tend to be available on EE.

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 a further 20 destinations that are outside of Europe (including the USA, Australia and New Zealand).

Network	Minutes	Texts	Internet	Monthly Cost
	Unlimited	Unlimited	8GB	£9.00
	Unlimited	Unlimited	4GB	£10.00
	Unlimited	Unlimited	12GB	£13.00
	Unlimited	Unlimited	100GB	£18.00
	Unlimited	Unlimited	30GB	£18.00
	Unlimited	Unlimited	Unlimited	£20.00

Aside from Three’s SIM only deals, EE’s 5G Smart SIMs have an optional “Roam Further” swappable benefit. This gives you inclusive roaming in the USA, Canada, Mexico, Australia and New Zealand. Vodafone’s Unlimited Max plan includes roaming in a further 29 destinations outside Europe. Most other mobile networks only offer inclusive roaming when you’re travelling within Europe.

Best SIM Card For Unlimited Data

If you’re looking for a SIM-only deal with unlimited data, you can choose from giffgaff, Three, SMARTY, Vodafone or Virgin Mobile.

All of these plans will allow you to use your mobile phone as much as you like without you needing to worry about running out of data mid-month.

Network	Minutes	Texts	Internet	Monthly Cost
	Unlimited	Unlimited	Unlimited	£18.75 1 month
	Unlimited	Unlimited	Unlimited	£20.00 12 months
	Unlimited	Unlimited	Unlimited	£23.00 12 months
	Unlimited	Unlimited	Always-On	£25.00 1 month
	Unlimited	Unlimited	Unlimited	£32.00 12 months
	Unlimited	Unlimited	Unlimited	£33.00 18 months
	Unlimited	Unlimited	Unlimited	£34.00 12 months

On Vodafone, the maximum download speeds you can access will differ depending on which unlimited plan you choose. You can get up to 2Mbit/s speeds on the Unlimited Lite price plan (£23/month), up to 10Mbit/s on the Unlimited plan (£26/month) and uncapped speeds on the Unlimited Max plan (£30/month).

With giffgaff’s Always-On Data, you’ll get 4G speeds on the first 40GB per month. After this, maximum download speeds will be restricted to 384kbit/s between 8am and midnight each day. Unlimited data plans from other mobile networks have no such restrictions on download speed.

Virgin Mobile’s unlimited data plan is only available to Virgin TV and home broadband customers.

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 more information on specific SIM-only deals, please click through to the relevant mobile network’s website. You can also read our in-depth mobile network and tariff reviews.