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:

How much data do you want on your plan each month?

How long are you willing to commit for on a contract?

Which networks would you be happy to take a plan from?

Showing 123 of 123 price plans that match your criteria

NetworkMinutesTextsInternetMonthly
Cost
iD Mobile500Unlimited1GB£5.00
1 month
Lebara Mobile500Unlimited1GB£5.00
1 month
SmartyUnlimitedUnlimited500MB£5.00
1 month
ASDA Mobile200Unlimited500MB£5.00
1 month
VodafoneUnlimitedUnlimited1.5GB£6.00
12 months
Sky MobileUnlimitedUnlimited1GB£6.00
12 months
giffgaff300500500MB£6.00
1 month
Plusnet MobileUnlimitedUnlimited2.5GB£7.00
1 month
iD Mobile1,200Unlimited2.5GB£7.00
1 month
ASDA Mobile300Unlimited2GB£7.00
1 month
Virgin Mobile1,500Unlimited1GB£7.00
12 months
SmartyUnlimitedUnlimited2GB£7.50
1 month
Tesco Mobile5005,0002GB£7.50
12 months
VodafoneUnlimitedUnlimited3GB£8.00
12 months
Plusnet MobileUnlimitedUnlimited3GB£8.00
1 month
giffgaff500Unlimited2GB£8.00
1 month
ThreeUnlimitedUnlimited8GB£9.00
12 months
iD MobileUnlimitedUnlimited3GB£9.00
1 month
Plusnet MobileUnlimitedUnlimited5.5GB£9.50
12 months
Plusnet MobileUnlimitedUnlimited5GB£9.50
1 month
Sky MobileUnlimitedUnlimited10GB£10.00
12 months
Virgin Mobile5,000Unlimited10GB£10.00
12 months
VOXIUnlimitedUnlimited8GB£10.00
1 month
Plusnet MobileUnlimitedUnlimited8GB£10.00
1 month
giffgaffUnlimitedUnlimited6GB£10.00
1 month
VodafoneUnlimitedUnlimited6GB£10.00
12 months
SmartyUnlimitedUnlimited4GB£10.00
1 month
Lebara MobileUnlimitedUnlimited4GB£10.00
1 month
Superdrug MobileUnlimitedUnlimited4GB£10.00
1 month
ThreeUnlimitedUnlimited4GB£10.00
24 months
Plusnet MobileUnlimitedUnlimited4GB£10.00
12 months
ASDA Mobile600Unlimited4GB£10.00
1 month
Tesco Mobile5005,0004GB£10.00
12 months
O21,000Unlimited2GB£10.00
18 months
Plusnet MobileUnlimitedUnlimited7.5GB£11.00
12 months
Plusnet MobileUnlimitedUnlimited7GB£11.00
1 month
VodafoneUnlimitedUnlimited1GB£11.00
12 months
VodafoneUnlimitedUnlimited1GB£11.00
18 months
O21,000Unlimited1GB£11.00
12 months
giffgaffUnlimitedUnlimited10GB£12.00
1 month
iD MobileUnlimitedUnlimited6GB£12.00
1 month
ASDA Mobile800Unlimited5GB£12.00
1 month
ThreeUnlimitedUnlimited4GB£12.00
12 months
Sky MobileUnlimitedUnlimited3GB£12.00
12 months
Tesco Mobile5,0005,0008GB£12.50
12 months
ThreeUnlimitedUnlimited12GB£13.00
24 months
iD MobileUnlimitedUnlimited10GB£13.00
1 month
O2UnlimitedUnlimited3GB£13.00
12 months
VodafoneUnlimitedUnlimited1GB£13.00
1 month
VOXIUnlimitedUnlimited20GB£15.00
1 month
giffgaffUnlimitedUnlimited15GB£15.00
1 month
Tesco Mobile5,0005,00015GB£15.00
12 months
ThreeUnlimitedUnlimited12GB£15.00
12 months
Plusnet MobileUnlimitedUnlimited12GB£15.00
12 months
Plusnet MobileUnlimitedUnlimited11GB£15.00
1 month
SmartyUnlimitedUnlimited8GB£15.00
1 month
ASDA Mobile1,000Unlimited8GB£15.00
1 month
Lebara MobileUnlimitedUnlimited6GB£15.00
1 month
VodafoneUnlimitedUnlimited5GB£15.00
12 months
VodafoneUnlimitedUnlimited5GB£15.00
18 months
iD MobileUnlimitedUnlimited14GB£16.00
1 month
O2UnlimitedUnlimited9GB£16.00
12 months
ThreeUnlimitedUnlimited4GB£16.00
1 month
EEUnlimitedUnlimited1GB£16.00
12 months
VodafoneUnlimitedUnlimited5GB£17.00
1 month
BT MobileUnlimitedUnlimited5GB£17.00
12 months
Tesco Mobile5,0005,00020GB£17.50
12 months
ThreeUnlimitedUnlimited100GB£18.00
12 months
Virgin Mobile5,000Unlimited45GB£18.00
12 months
ThreeUnlimitedUnlimited30GB£18.00
24 months
Sky MobileUnlimitedUnlimited15GB£18.00
12 months
O2UnlimitedUnlimited15GB£18.00
18 months
O2UnlimitedUnlimited12GB£18.00
12 months
SmartyUnlimitedUnlimitedUnlimited£18.75
1 month
ThreeUnlimitedUnlimited12GB£19.00
1 month
ThreeUnlimitedUnlimitedUnlimited£20.00
12 months
ThreeUnlimitedUnlimitedUnlimited£20.00
24 months
VOXIUnlimitedUnlimited45GB£20.00
1 month
giffgaffUnlimitedUnlimited40GB£20.00
1 month
ThreeUnlimitedUnlimited30GB£20.00
12 months
O2UnlimitedUnlimited25GB£20.00
12 months
Tesco Mobile5,0005,00025GB£20.00
12 months
iD MobileUnlimitedUnlimited20GB£20.00
1 month
VodafoneUnlimitedUnlimited20GB£20.00
12 months
VodafoneUnlimitedUnlimited20GB£20.00
18 months
EEUnlimitedUnlimited20GB£20.00
12 months
BT MobileUnlimitedUnlimited15GB£20.00
12 months
ASDA MobileUnlimitedUnlimited12GB£20.00
1 month
Lebara MobileUnlimitedUnlimited12GB£20.00
1 month
Virgin MobileUnlimitedUnlimited120GB£22.00
12 months
O2UnlimitedUnlimited40GB£22.00
18 months
VodafoneUnlimitedUnlimited20GB£22.00
1 month
VodafoneUnlimitedUnlimitedUnlimited£23.00
12 months
VodafoneUnlimitedUnlimitedUnlimited£23.00
18 months
O2UnlimitedUnlimited15GB£23.00
12 months
ThreeUnlimitedUnlimitedUnlimited£24.00
1 month
ThreeUnlimitedUnlimited30GB£24.00
1 month
giffgaffUnlimitedUnlimitedAlways-On£25.00
1 month
VodafoneUnlimitedUnlimitedUnlimited£25.00
1 month
O2UnlimitedUnlimited100GB£25.00
18 months
EEUnlimitedUnlimited80GB£25.00
12 months
O2UnlimitedUnlimited50GB£25.00
12 months
Lebara MobileUnlimitedUnlimited20GB£25.00
1 month
EEUnlimitedUnlimited20GB£25.00
12 months
ASDA MobileUnlimitedUnlimited15GB£25.00
1 month
ThreeUnlimitedUnlimitedUnlimited£26.00
1 month
VodafoneUnlimitedUnlimitedUnlimited£26.00
12 months
VodafoneUnlimitedUnlimitedUnlimited£26.00
18 months
EEUnlimitedUnlimited100GB£27.00
12 months
VodafoneUnlimitedUnlimitedUnlimited£28.00
1 month
VodafoneUnlimitedUnlimitedUnlimited£30.00
12 months
VodafoneUnlimitedUnlimitedUnlimited£30.00
18 months
BT MobileUnlimitedUnlimited25GB£30.00
12 months
Virgin MobileUnlimitedUnlimitedUnlimited£32.00
12 months
VodafoneUnlimitedUnlimitedUnlimited£32.00
1 month
O2UnlimitedUnlimitedUnlimited£33.00
18 months
EEUnlimitedUnlimitedUnlimited£34.00
12 months
O2UnlimitedUnlimitedUnlimited£35.00
12 months
O2UnlimitedUnlimited40GB£38.00
12 months
EEUnlimitedUnlimitedUnlimited£39.00
12 months
BT MobileUnlimitedUnlimited60GB£40.00
12 months
Sky MobileUnlimitedUnlimited50GB£40.00
12 months
EEUnlimitedUnlimitedUnlimited£44.00
12 months

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 AllowanceCheapest PlanCheapest Mobile Network
500MB Data£5.00/monthiD Mobile & Lebara Mobile
1GB Data£5.00/monthiD Mobile & Lebara Mobile
2GB Data£7.00/monthPlusnet Mobile & iD Mobile
3GB Data£8.00/monthVodafone & Plusnet Mobile
4GB Data£9.00/monthThree
8GB Data£9.00/monthThree
12GB Data£13.00/monthThree
20GB Data£15.00/monthVOXI
100GB Data£18.00/monthThree

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:

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.

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:

NetworkMinutesTextsInternetMonthly
Cost
ASDA Mobile300Unlimited2GB£7.00
SmartyUnlimitedUnlimited2GB£7.50
giffgaff500Unlimited2GB£8.00
VOXIUnlimitedUnlimited8GB£10.00
Lebara MobileUnlimitedUnlimited4GB£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:

NetworkMinutesTextsInternetMonthly
Cost
EEUnlimitedUnlimitedUnlimited£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).

NetworkMinutesTextsInternetMonthly
Cost
ThreeUnlimitedUnlimited8GB£9.00
ThreeUnlimitedUnlimited4GB£10.00
ThreeUnlimitedUnlimited12GB£13.00
ThreeUnlimitedUnlimited100GB£18.00
ThreeUnlimitedUnlimited30GB£18.00
ThreeUnlimitedUnlimitedUnlimited£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.

NetworkMinutesTextsInternetMonthly
Cost
SmartyUnlimitedUnlimitedUnlimited£18.75
1 month
ThreeUnlimitedUnlimitedUnlimited£20.00
12 months
VodafoneUnlimitedUnlimitedUnlimited£23.00
12 months
giffgaffUnlimitedUnlimitedAlways-On£25.00
1 month
Virgin MobileUnlimitedUnlimitedUnlimited£32.00
12 months
O2UnlimitedUnlimitedUnlimited£33.00
18 months
EEUnlimitedUnlimitedUnlimited£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.

Your Comments 131 so far

We'd love to hear your thoughts and any questions you may have. So far, we've received 131 comments from readers. You can add your own comment here.

  • Hi Ken,
    Extremely useful information here. Thanks.
    I’m currently using 3 on a monthly rolling contract, how do I switch to the 3 deal you provided above?

    Coz I’m not switching so I don’t need a PAC code, and if I walk into the shop or logon to my3 I cannot view any deals like yours. Please kindly instruct me what I should do.

    Many thanks.

    • Hi Jon,
      Thanks for your comment. There are really two ways you can do this:
      1. You can process it as an upgrade within Three (i.e. go to Three and see what plans are available for you to upgrade to). You might not have full access to the range of price plans listed here.
      2. The table above contains lots of new customer price plans, which might be priced more competitively to attract new customers to Three. They often don’t want existing customers to move on to those plans (especially if they’re giving you more data for a lower monthly price). If you’d like to take advantage of them, you can easily port your phone number out to another network and then back in to Three. Order a free Pay As You Go SIM card from another network and use a PAC Code to move your phone number onto that network and back.
      Hope this helps,
      Ken

  • Does VOXI/ Giffgaff have access to international roaming? If yes, what countries in general do they cover? If no, can you advise me on sim-only deals that do not require credit history that also have access to international roaming?

  • Hi Ken

    I have a question about using sim cards abroad.

    If one travels to a number of countries in the far east – Philippines, Malaysia etc.. is there a sim card which you can buy in the UK topped with data, minutes and SMS and use in these countries and others?

    I am not talking about the usual big companies like O2, Vodafone, 3 etc. Perhaps a small company. I ask because its very frustrating travelling from country to country and having to purchase sim cards in each different country.

    I have heard of WorldSIM which offers an international sim but I know nothing about this company – can you shed any light?

    Thanks

    • Hi Goolash,
      Thanks for your comment. Like you said, there unfortunately aren’t any mainstream companies that offer a worldwide international SIM card. There are a number of companies like WorldSim, Truphone, etc but unfortunately I don’t have any first-hand experience of them. I do feel like things are generally getting better amongst the main providers (e.g. with Three’s Go Roam, EE’s Roam Further Pass, Vodafone’s Global Roaming Plus, etc) and hopefully we’ll see this continue.
      Ken

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