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Cheapest SIM-only deals in May

Cheap SIM-only deals: All you need to know

Cheap SIM only deals icon

A SIM-only deal is a fantastic way to save money on your mobile. Getting a SIM for a phone you've already paid off or bought outright is almost always better value than a pay-monthly contract, and it gives you a lot more choice and flexibility over your mobile plan.

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Here you'll find the cheapest SIMs we can find on a wide range of networks. We've done the hard work of tracking them down, so you don't have to.

Who is the cheapest SIM only network?

O2's great for freebies. But EE takes the crown when it comes to speeds and coverage.Here we take a look at what each of the major networks has got to recommend them. And we've picked out some great cheap SIM only deals for each network too.

Cheap SIM only deals from EE

  • EE sim only
    4G
    • 1GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £16.00 per month
    12 month contract From EE Mobile
  • EE sim only
    4G
    • 20GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £22.00 per month
    12 month contract From EE Mobile
  • EE sim only
    4G
    • 40GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £25.00 per month
    12 month contract From EE Mobile

Surveys consistently rate EE as the best network for breadth of coverage and speeds.

Choose a Smart SIM and you'll get Swappable Benefits, with the option to choose a different customer benefit from month to month.

Such as the BT Sport app or the option to use your UK allowances in a wider range of countries.

Cheap SIM only deals from O2

Included on all SIM only deals, O2's Rewards scheme gets you discounts at high-street stores and restaurants.

Membership of its Priority scheme is also free with all O2 SIMs and entitles you to priority booking at O2 venues.

Cheap SIM only deals from Vodafone

  • Vodafone sim only
    5G
    • 5GB of 5G data
    • Unlimited minutes
    • Unlimited texts
    • £16.00 per month
    12 month contract From Vodafone
  • Vodafone sim only
    5G
    • 20GB of 5G data
    • Unlimited minutes
    • Unlimited texts
    • £21.00 per month
    12 month contract From Vodafone

All Vodafone SIM-only customers are enrolled in its VeryMe Rewards scheme. Incentives include pre-sale tickets for events, as well as money-off deals with the likes of Asos, Costa Coffee and Greggs.

Depending on the SIM you choose, you can also get inclusive roaming in 48 or 77 destinations.

An on select contracts you can pick from a 12-month subscription to NowTV, Amazon Video, Spotify or Sky Sports Mobile.

Cheap SIM only deals from Three

  • Three sim only
    4G
    • 8GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £8.00 per month
    12 month contract From Three Mobile

Three's excellent Go Roam Around the World scheme offers inclusive roaming in 71 locations worldwide and comes free on Advanced SIM only plans.

Essential SIM only deals offer inclusive roaming in 48 locations, which still compares well with other networks.

Cheap SIM only deals from iD Mobile

iD Mobile's SIM only deals are among the UK's cheapest. But you don't get quite the same sort of customer incentives as you do with larger, better known networks.

However, all SIMs still offer inclusive roaming in 50 destinations, as well as data rollover.

Cheap SIM only deals from VOXI

  • VOXI sim only
    4G
    • 45GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • Unlimited social data
    • £20.00 per month
    1 month contract From VOXI

VOXI plans' key selling point is that you can spend as much time as you like on social media sites without eating into your data allowance.

SIM only plans also feature inclusive roaming in 48 locations for no extra charge.

How to compare cheap SIM-only deals

mobile phone network logos

Take a look at all the SIM deals in our mobile comparison table.

You can apply all kinds of filters in the sidebar, so you can see every deal that fits what you need.

Then, to find the best value ones, sort them by cost. This will order them by price and show you the cheapest ones first.

Or, set a maximum budget using the cost details filter - this way you'll only see deals that charge below a certain price.

We recommend choosing the deal gives you the allowance and features that you need at the lowest-priced tariff.

And don't worry - even if you switch mobile networks, you can still keep your current phone number.

Tips for finding cheap SIM-only deals

The best way to find a cheap SIM deal is to follow the steps above using our comparison tool.

It'll take into account things like special offers running right now, as well as the kind of plans you need - but there are a few other things you can do to guarantee a good deal.

Go pay-monthly

Pay-monthly SIM deals are usually far better value than pay-as-you-go ones - especially if you use 4G mobile internet on your phone, which can get pretty expensive without a monthly allowance.

Our comparison tool lets you compare just those SIMs that are pay-monthly or at least function that way, so you can see how cheap they really are per month.

Choose a small network or MVNO

'Mobile virtual network operators' are mobile providers that piggyback on other networks to deliver their services.

You get the same coverage as you would on the larger network - namely EE, O2, Three, or Vodafone - but with the specific benefits and prices of the 'virtual' one.

And because the network has lower operating costs, prices for you are usually much, much lower.

For cheap SIM deals, look to these kinds of networks, such as:

Get a 12-month contract

  • Three sim only
    4G
    • 8GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £8.00 per month
    12 month contract From Three Mobile
  • Vodafone sim only
    4G
    • 8GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £8.00 per month
    12 month contract From Vodafone

Long-term contracts on SIMs are usually quite a bit cheaper than 30-day ones with the same allowance from the same network.

If you don't mind committing for a full year or so, a 12-month contract can save you a bit of money even on larger, fancier, feature-packed networks.

Look out for existing customer deals

A number of providers offer special deals for loyal customers. Keep an eye out for these deals from your current mobile network, as there may be a cheaper SIM offer available that new users can't get.

Look out for SIM deals from your broadband or TV provider too. BT, EE, Plusnet, Sky, and Virgin all have bonuses or special offers for customers who take out a mobile plan on top of their current subscription.

Set a monthly spending cap

Some networks let you set a cap on your plan, which ensures you'll never spend above a certain amount each month.

It's a handy way to eliminate bill shock and keep your spending under budget, especially if you're prone to buying add-ons or making international calls.

Networks that let you set caps on your SIM include:

  • BT Mobile
  • iD Mobile
  • Plusnet Mobile
  • Tesco Mobile

Get a smaller allowance

The lower the monthly allowance on your plan, the less your SIM will cost. A small compromise here could mean surprisingly big savings over the year.

However, make sure you still have enough to cover your usage - if you use up your allowance every month, you'll have to shell out more on add-ons.

Pay-as-you-go SIM-only deals

If a long-term mobile contract doesn't appeal, you can always go for a Pay As You Go (PAYG) SIM deal - a great option if you want to keep your old handset.

Frequently asked questions

Is it cheaper to get a SIM only plan?

It's pretty much always cheaper to buy a SIM only plan than a standard phone-and-tariff contract. That's because unlike the latter, with a SIM only deal you're only paying for your monthly allowances and won't be paying off the cost of a new phone.

Can I keep my number when I get a new SIM?

You certainly can. And all you need is a PAC (porting authorisation code). The best and simplest way to get one is to use networks' text to switch scheme, which simply requires you to text 'PAC' to 65075. You'll then receive the code you need and that you can give to the network you want to join.

Will I lose my service if I switch to a SIM only deal from another network?

When you give your PAC to the network you're joining, you'll still be able to make calls, send texts and use the internet on your phone exactly as before. At the point in your switch when your network is actually switching your number, you may be left without service for a matter of a few minutes.

To check when the switchover is complete, insert your new SIM in your phone and turn the handset on. If your phone is showing that you've got a service/coverage and you make and calls and use the internet, you're good to go.

Can I switch my SIM only deal with my existing network?

If you're on a 30-day rolling contract SIM only deal, you can switch to another deal with your network whenever you like. You'll just need to give 30 days' notice.

If you're on an 12-month or 18-month SIM only contract, your network will almost certainly allow you to upgrade to a pricier plan with bigger allowances. And you may be able to downgrade to a cheaper plan. But that's not guaranteed. You'll need to speak to your network and explain your circumstances.

Will there be a credit check on my SIM only plan?

On 30-day SIMs, there's no credit check to pass. On longer term SIM contracts, you will generally have to pass a credit check, but it won't be anything like as stringent as they are for standard phone-and-SIM contracts.

Can I get cheap 5G SIM only plans?

You can. 5G and 4G SIMs from the major networks are comparably priced, so you won't be paying any extra for faster speeds. As with 4G, prices for 5G SIM only deals start at about £5 per month.

Is pay as you go cheaper than pay monthly?

No, pay monthly is generally cheaper. In the sense that you get more for your money. However, pay as you go is more undeniably more flexible, allowing you to completely pare down your usage at a stroke if you're really trying to save money.