SIM Only Deals: The UK’s Best Value SIM Cards For Your Smartphone

June 20th, 2017

You can often save hundreds of pounds per year by getting a low-cost SIM card for your mobile phone. We compare the UK’s best value smartphone SIM-only deals.

SIM card for SIM Only tariffA great way to save money on your mobile phone bill is to change your tariff to a SIM-only deal. Compared to a normal mobile contract, you can normally save hundreds of pounds per year whilst keeping the same phone number as before. You’ll also get lots of flexibility with the choice of either a 12-month or 1-month contract.

In this article, we’ll review and compare the UK’s best value smartphone SIM-only deals. We’ll compare SIM-only deals from 12 different mobile networks: from the big names like EE and O2, to lower-cost virtual network operators such as ASDA Mobile, giffgaff and iD Mobile.

SIM Only Deals: How Do They Work?

A SIM-only deal is a low-cost airtime-only tariff for your mobile phone. With a SIM-only deal, you’ll get a new low-cost SIM card that slots inside your unlocked smartphone. Typically, you can save more than £100 per year whilst still getting great coverage and being able to keep your existing phone number.

Here are three key things you should know when choosing a SIM-only deal:

1. You’ll always get coverage from EE, O2, Three or Vodafone

  • EE
  • O2
  • Three
  • Vodafone

The UK has only four coverage providers: all other mobile networks will piggyback on one of the four.

With SIM-only deals, you’re currently able to choose from 12 different mobile networks. While this appears to be complicated at first glance, it’s worth being aware there are only four underlying network coverage providers. All other mobile networks piggyback on coverage from the big four so you’ll get the exact coverage when using any of these networks:

To find out more and to compare the coverage in your area, please see our list of UK mobile phone coverage checker tools.

2. You can keep your current mobile number

It’s a straightforward process to keep your current phone number when moving to a SIM-only deal. If you’re changing mobile networks, you’ll need to obtain a PAC Code from your old mobile network. The PAC Code should then be given to your new mobile network. The process of transferring your phone number takes about one working day: our PAC Code Finder can take you through the process one step at a time.

3. You might need to unlock your smartphone

If your smartphone was originally provided by another mobile network (e.g. on a Pay Monthly contract or on Pay As You Go), it might be necessary to first unlock it. For more information, see our guides on unlocking an iPhone and unlocking a Samsung Galaxy smartphone.

Recommended Deals

The best SIM-only deal will depend very much on your specific requirements (i.e. it depends on who the SIM card is for and what features are required from the mobile network).

For Families & Spend Control

For families, BT Mobile is our recommended network (specifically, their Family SIM offer).

With BT Mobile’s Family SIM, customers can have up to five SIM cards on one Family account. Each SIM card has its own individual allowance along with a built-in spend cap to prevent unexpected out-of-allowance charges. Customers get an online dashboard for controlling their family’s spending, and have the ability to delegate control on a SIM-by-SIM basis. There are also discounts available when multiple family members join BT Mobile, with the size of the discount increasing as more family members join.

The following table shows the cost of your first BT Mobile SIM card (assuming you’re also a BT Broadband customer). Additional Family SIM cards will come with a further discount.

BT MobileUnlimitedUnlimited3GB£8.00
inc. £5 discount
BT MobileUnlimitedUnlimited5GB£11.00
inc. £5 discount
BT MobileUnlimitedUnlimited12GB£16.00
inc. £5 discount
BT MobileUnlimitedUnlimited6GB£16.00
inc. £5 discount
BT MobileUnlimitedUnlimited20GB£20.00
inc. £5 discount

For more information, please see our review of BT Mobile and the Family SIM offer.

For Flexibility & No Credit Check

If you want ultimate flexibility and don’t want to undergo a credit check, our current recommendation is to get a free SIM card from ASDA Mobile.

For £10/month, you’ll get 600 minutes, unlimited texts and 2GB of 4G internet. The deal works on a pre-paid basis so you can easily pause or stop using the SIM card at any time (there’s no need to give 30 days notice like you would on most other mobile networks). You can also change your tariff at any time, including to ASDA’s Pay As You Go tariff of 8p/minute, 4p/text and 5p/MB.

ASDA Mobile600Unlimited2GB£10.00

ASDA Mobile offers 2G, 3G and 4G coverage from the EE network. For more information, please see our in-depth review of ASDA Mobile.

For Tethering & Personal Hotspot

If you’d like to get your other devices connected on-the-go (e.g. your laptop or tablet), it’s worth noting that only some mobile networks will allow you to tether. Some lower-cost mobile networks like iD Mobile and Virgin Mobile prohibit the use of tethering on their network. Three also prevents tethering for customers with a lower-cost Essential price plan.

The following table shows some of our recommended SIM-only deals for customers who want to be able to tether:

Tesco Mobile3,0005,0006GB£12.50

For more information, see our in-depth guide to tethering on UK mobile networks.

For Fastest Download Speeds

If you want access to the fastest 4G download speeds, EE is currently our recommended network for a new SIM-only deal. Most customers joining EE will have access to double-speed 4G, giving download speeds of up to 60Mbps and an average of around 24-30Mbps. Customers with a 4GEE Max SIM card will also have access to 4G+ (LTE-Advanced) if they live in London.


For more information, see our guide to double-speed 4G and also EE’s premium 4GEE Max tariff.

For International Roaming

For customers wanting inclusive international roaming in 60 destinations (including Europe, the USA, Australia, Brazil, Singapore and more), Three offers Feel At Home Around The World on their ‘Advanced’ Pay Monthly SIM cards. With Feel At Home, you can use your normal UK allowances when travelling abroad at no extra cost.


On Three’s lower-price Essential plans, Feel At Home Around The World is not available. However, customers with an Essential price plan will still have access to Feel At Home In Europe. For more information, see our full review of the Feel At Home offer or alternatively Three’s official webpage.

For Unlimited Data

  • giffgaff
  • Three

For customers wanting the peace of mind of unlimited data, suitable SIM-only deals are currently available from giffgaff and Three.

giffgaff has the cheapest available SIM card with unlimited data: just £20/month will get you Always-On data (unlimited downloads with tethering and 4G speeds on the 6GB per month). Three has a higher entry-level price for all-you-can-eat data, but gives you 30GB per month of personal hotspot and no limits on 4G usage.


For more information, please see our in-depth guide to unlimited data tariffs.

Deals By Price Range

For a full overview of SIM-only deals by price range, please jump to the relevant section of this article:

Less than £10/month

5 Pound Note

In the UK, you can get a SIM-only deal for less than £5/month.

If you’re looking for a super-cheap SIM-only deal, the cheapest options available on the market start from around £5/month.

Typically, the best value SIM cards in this price range come from iD Mobile and Plusnet Mobile (both of them offer 1-month rolling contracts). For instance, iD Mobile offers 250 minutes, 5000 texts and 1.5GB of internet for £5/month.

iD Mobile uses 3G & 4G coverage from Three while Plusnet Mobile offers 2G, 3G & 4G coverage from EE. iD Mobile is the own-brand mobile network from the Carphone Warehouse and Plusnet Mobile is the low-cost sub-brand of BT.

The following tables show a full list of SIM-only deals available for less than £10/month. 12-month contracts are shown on the left and 1-month rolling contracts are shown on the right.

12 month contracts

Sky Mobile00500MB£5.00
Tesco Mobile2505,000500MB£6.00
Virgin Mobile300Unlimited300MB£6.00
Tesco Mobile2505,000500MB£7.50
Tesco Mobile5005,000250MB£7.50
Tesco Mobile5005,0002GB£9.00
Virgin Mobile1,500Unlimited1GB£9.00
Tesco Mobile2505,0001GB£9.00
Tesco Mobile5005,000500MB£9.00
1 month contracts

iD Mobile5005,000500MB£3.99
iD Mobile5005,0001GB£5.00
Plusnet Mobile250500500MB£5.00
ASDA Mobile1252,000200MB£5.00
Plusnet Mobile1,500Unlimited2.5GB£7.00
ASDA Mobile300Unlimited1GB£7.00
iD Mobile5005,0002GB£7.50
Plusnet Mobile1,000Unlimited1GB£7.50
Tesco Mobile2505,000100MB£7.50
Tesco Mobile2505,000500MB£9.00

From £10/month

The vast majority of SIM only deals start from £10/month.

At the £10/month price point, there’s a huge variety of SIM-only deals.

On a 1-month contract, some of the best value deals are available from ASDA Mobile, giffgaff, iD Mobile and Plusnet Mobile. These will give you a monthly data allowance of up to 5GB along with high-speed 4G internet (ASDA and Plusnet Mobile use coverage from EE, whilst giffgaff uses coverage from O2 and iD Mobile uses coverage from Three).

On a 12-month contract, the best value deals currently have a smaller allowance of data compared to 30-day contracts. However, you may be able to get additional benefits when choosing a 12-month plan. For instance, Three has an “Advanced” SIM-only deal with inclusive roaming in many countries around the world (“Feel At Home Around The World”). Meanwhile, BT Mobile offers a 12-month SIM card with Family SIM discounts and spend control.

12 month contracts

Tesco Mobile5005,0001GB£10.00
Sky Mobile001GB£10.00
Tesco Mobile1,0005,000500MB£10.00
BT Mobile400Unlimited500MB£10.00
Tesco Mobile5005,0002GB£11.00
Virgin Mobile2,500Unlimited2GB£12.00
Tesco Mobile3,0005,0006GB£12.50
Tesco Mobile1,0005,0003GB£12.50
BT MobileUnlimitedUnlimited3GB£13.00
Virgin Mobile2,500Unlimited3GB£13.00
1 month contracts

iD Mobile5005,0005GB£10.00
Plusnet Mobile1,500Unlimited2GB£10.00
ASDA Mobile600Unlimited2GB£10.00
Tesco Mobile2505,0001GB£10.00
Tesco Mobile5005,0001GB£11.00
iD Mobile1,0005,0006GB£12.00
ASDA Mobile800Unlimited3GB£12.00
Tesco Mobile5005,0002GB£12.50

From £15/month

15 Pound NotesThere are a wide variety of SIM-only deals to choose from at the £15/month price point. Many mobile networks are offering unlimited calls & unlimited texts, and you can get a data allowance of up to 6GB per month.

In our opinion, Three’s 12-month “Advanced” plan is a good choice. You’ll get inclusive tethering & portable hotspot along with Feel At Home Around The World (the latter will allow you to use your phone in many countries around the world at no extra charge).

The following SIM-only deals are currently available from £15/month:

12 month contracts

Virgin Mobile2,500Unlimited4GB£15.00
Tesco Mobile1,5005,0004GB£15.00
Sky Mobile003GB£15.00
BT MobileUnlimitedUnlimited5GB£16.00
Tesco Mobile5,0005,00012GB£18.00
Tesco Mobile3,0005,0006GB£18.00
1 month contracts

iD Mobile2,0005,0006GB£15.00
ASDA Mobile1,000Unlimited5GB£15.00
Plusnet MobileUnlimitedUnlimited4GB£15.00
Tesco Mobile1,0005,0003GB£15.00
Tesco Mobile1,5005,0004GB£18.00

From £20/month

20 Pound NoteAt the £20/month price point, most mobile networks are offering unlimited calls and unlimited texts. You can also get huge amounts of data at this price point (e.g. 30GB of high-speed 4G internet on the £22/month Advanced SIM card from Three).

For unlimited downloads and greater flexibility, we’d recommend choosing giffgaff’s £20 goodybag. For £20/month, you’ll get unlimited minutes, unlimited texts and Always-On data (unlimited downloads with tethering and 4G speeds on the first 6GB per month).

The following deals are also available from £20/month:

12 month contracts

Sky Mobile005GB£20.00
BT MobileUnlimitedUnlimited12GB£21.00
BT MobileUnlimitedUnlimited6GB£21.00
Tesco Mobile5,0005,00012GB£23.00
Virgin Mobile5,000Unlimited20GB£24.00
1 month contracts

ASDA MobileUnlimitedUnlimited8GB£20.00
Tesco Mobile3,0005,0006GB£23.00

From £25/month

The following SIM-only deals are available for £25/month or more:

12 month contracts

BT MobileUnlimitedUnlimited20GB£25.00
Tesco Mobile5,0005,00020GB£28.00
1 month contracts

Tesco Mobile5,0005,00012GB£28.00

£30/month and more

The following SIM-only deals are available for £30/month or more:

12 month contracts

Tesco Mobile5,0005,00025GB£32.00
Tesco Mobile5,0005,00030GB£35.00
1 month contracts


More Information

For more information about the mobile networks listed in this article, please see our in-depth mobile network reviews. You may also find it helpful to read our guides on comparing mobile coverage, transferring your phone number and unlocking your smartphone.

For more information about a specific SIM-only deal, please refer to the relevant mobile network’s website. You can click through to their website as follows: ASDA Mobile, BT Mobile, EE, giffgaff, iD Mobile, O2, Plusnet Mobile, Sky Mobile, Tesco Mobile, Three, Virgin Mobile and Vodafone.

Prices change on an occasional basis. For this reason, you should always double-check the details on the mobile network’s website before signing up to any deal.

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About Ken

Ken Lo

My passion is helping people to get the most out of their mobile phone. I've been blogging at Ken's Tech Tips since 2005.

Aside from writing about mobile technology, my interests are in software development, digital marketing and physics. Outside of the blog, I work with numerous technology companies helping them to explain their product and helping them to market it to consumers. Please get in touch for more information.

Your Comments

We'd love to hear your thoughts and any questions you may have. So far, we've received 103 comments from readers. You can add your own comment here.

  1. steve said:

    Help! I can’t be the only dinosaur left in the UK. I use a phone to make phone-calls and the occasional text. .
    Talk mobile suited me down to the ground, but , sadly, Vodafone decided to shut it down.

    I did get a freeby (eventually!) to transfer to Voda. they are scandalously expensive for payg. Telepnone “help” is a joke, BUT they have opened a call-centre in Manchester…that works, they are English and understand the culture and don’t lose anything in the translation….5 minutes to sort -out a problem their foreign call – centre couldn’t resolve in 2 1/2 HOURS…..guess I won’t stay with them!

    What -about 1p? seems to fill my needs. PAYG, ancient (2g ) ? phone, cheap rate, long (4-months) active life for £10 credit- blocks. I’ll look again through your site but didn’t see that provider.

    next nearest for value appears to be ID, £3.50 a month is OK, but only 3G and newer phones. both deals appear to be better value than Asda……am I missing something?
    Great site, found you through Google.

    1. steve replied:

      Found your review on 1p. by far the cheapest option on payg, if I read the small print correctly…..anyway, I’ve signed up. Hate contracts, as prices seem to be dropping daily in this now-mature market, where all providers seem to be desperate to flog their airtime.

      It wouldn’t surprise me to see a return of the reduced evening and weekend tariff -structure, in order to sweat their assets a little bit more.

      1. Ken replied:

        Hi Steve,
        Many thanks for the feedback! As you said, 1pMobile is a Pay As You Go option so they’re listed in a separate part of the website from these Pay Monthly SIMs 🙂 I think 1p is a good option if you’re a fairly light user with occasional usage. Of course, you just need to keep an eye out for the 120-day requirement (so I recommend you either use auto-topup or you put something in the diary to top up your account every 3 months).

  2. WM said:

    Very helpful! I’m planning on coming to the UK next month, and this will be great for making a carrier choice

    1. Ken replied:

      Hi WM,
      Many thanks for the kind feedback! As a visitor to the UK, it’s worth being aware you’ll only be able to get a Pay As You Go deal. However, don’t despair, as you can get really good value on Pay As You Go as well.
      The reason you won’t be able to get a contract is because it will require you to pass a UK credit check.
      Hope this helps,

  3. Oliver Scott said:

    Ken missed out on a deal that EE is currently running that I switched to personally, 20 GB, unlimited calls and texts for £20 a month + 3 months BT sport app and apple music use.

    1. Ken replied:

      Hi Oliver,
      Thanks for the heads up about this! I am actually listing this in the table above, though it’s possibly a little bit confusing (the tariff is actually £19.99/month, so is listed the “From £15/month” section rather than “From £20/month” section). Definitely a great deal, especially if you get it with the voucher code offer!

      1. Oliver Scott replied:

        I’d have listed it up to the “£20/month” but this isn’t haha!
        Also you have another EE offer for £19.99 for only 2GB which would only add to the confusion of whether that’s a typo. Anyhow, glad to be of assistance. I think this offer will only be valid for this month though, atleast that’s what I was told at the shop. This bundle’s regular price is £34.99.
        Keep doing what you do and have a good one.

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