Most people these days get a new phone on contract, but if you can afford to pay for that phone upfront (or you're now out of contract on your phone) it makes much better financial sense to get a SIM-only tariff. In fact, our round-up of the best SIM deals in the UK could save you a fortune in the long run.

A big concern for many is that you'll lose your current phone number if you switch. But that's not true: you can transfer your current phone number to a new network and the whole process is simple if you use the text-to-switch service.

Here, we've picked the very best SIM-only deals available right now. 

The best SIM-only deals right now

Three SIM deals Three's crazy unlimited SIM-only deal is back for Black Friday. You can get the first six months for just £10 per month, which then doubles for the rest of the contract (which is 24 months in total). There's also 100GB for £16 per month with no cost increase. In addition, new customers can get a £50 gift card when they switch to Three. View deal here.  

Smarty Logo Smarty is doubling the data of its 50GB contract for Black Friday, which means you can get 100GB of data on a monthly rolling plan for just £15 per month, with unlimited texts and calls, and roaming up to 12GB in certain EU countries. View deal here

ID Mobile

iD Mobile also currently has a great limited-time unlimited data offer, if you don't mind cashback. You can get the iD unlimited SIM for just £10 per month for 12 months. View deal here. 

It's also worth checking out 1pMobile. Whilst this is a Pay As You Go offer, it offers your usage at the following prices: 1p per minute on calls, 1p per text and 1p per MB of data used. If your usage is low, then this could be a good option. Check out 1pMobile here

Also read: Best SIM deals for kids and best SIM deals for students

Which SIM-only tariff do you need?

Unlike smartphone contracts, which typically stretch to 24 months, SIM-only deals are much shorter. Most SIM-only deals come with 12-month contracts, but there are many rolling monthly contracts – sometimes at the same price – that are ideal for visitors to the UK or for anyone who doesn't want to be tied in.

The price you pay per month will largely depend on how many minutes and texts you need, and how much data you require.

Pinning down the best SIM-only contract is tricky due to the huge number of combinations of minutes, texts and data available. Some providers also offer deals with cashback redemption - which means that you won't be billed the amount advertised, but you can claim your refunds from the provider. 

Most people will fall into one of three camps that we'll focus on here: those who simply want to make the odd call or text, and use their PC to go online; those who make calls and texts, go online, check emails, use apps and perhaps watch the odd video; and those who are permanently glued to their smartphone.

Or, to put that more simply, light, moderate and heavy users.

SIM deals for light use

There are plans available from not much more than £5 per month if you plan on using your SIM for light use:

ID Mobile All of iD mobile's contracts offer bill capping, data rollover and Roam like at Home, making it an even more appealing option with no nasty surprises. This Black Friday, you can get 16GB data with unlimited minutes and texts for just £8 per month on a rolling contract, along with five months worth of Apple Music, Apple Arcade or Apple News+ completely for free. View deal here

Lebara Mobile Lebara also offers some great light plans, such as the 2GB rolling plan for £5 per month. With this, you also get 100 minutes to 41 international countries - great if you need to call family abroad. You also get 1000 UK minutes and 1000 texts. View deal here.

GiffGaff Giffgaff is currently offering more data on all of its goodybags, including the golden goodybag which is growing from 10GB to 15GB for just £10 per month. This also includes unlimited texts and calls, plus 5G connectivity. View deal here

SIM deals for moderate use

If you use 20GB or above, it's worth considering a moderate use SIM plan. Here's some of the most competitive right now:

Voxi logo For moderate use, and also for teenagers, the best deal is from Voxi, which is powered by Vodafone. It's an interesting one because social media usage is unlimited and won't eat into your data. Currently, you can grab 15GB of data, unlimited social media, unlimited calls and texts and 5G, all for £10 per month on a monthly rolling contract. There are also other offers available for Black Friday.  View deal here.

ID Mobile You can also get a very cheap deal from iD Mobile via Mobiles.co.uk, which includes 40GB of data, unlimited calls and texts and 5G all for £10 per month on a rolling contract. In addition, any unused data will be rolled over to the next month. View deal here.

Vodafone Logo

For Black Friday, Mobiles.co.uk has a great offer with Vodafone. You can grab 50GB of data, unlimited minutes and texts and 5G coverage for just £6.50 per month, with £132 cash by redemption. View deal here. Mobiles.co.uk also has other Black Friday offers, with 100GB plans going for under a tenner. 

SIM deals for heavy use

For anyone who wants the freedom to text and use the internet as much as they like, our favourite deal is Three's unlimited SIM for £10 for the first six months. However, there are other options to consider:

O2 Logo O2 throws in perks on some of its biggest data plans. The 250GB for £20 per month on a 24-month plan includes six months worth of Disney+ for streaming, plus free minutes, texts and 5G. View deal here.

Tesco Mobile Tesco Mobile also has a decent offer for Black Friday for Clubcard members. It's free to sign up for a Clubcard, and you can also get discounts on your shopping and more perks. Grab unlimited data, unlimited minutes, texts and 5G, all for £20 for 12 months. View deal here. 

Superdrug also has a great flexible option which includes unlimited data, unlimited minutes, unlimited texts, 4G and extra card points for Superdrug members. All of this costs £20 per month and is available as a monthly rolling contract. View deal here

Tablet plans (Data SIMs)

If you're looking for a SIM for your tablet, then you can't simply take the SIM out of your phone and stick it in another device. You need to get a SIM that uses a data-only plan (and don't forget that not all tablets offer SIM-card slots, in which case you'll only be able to connect to WiFi).

How much data you need will very much depend on the activities you intend to enjoy on your tablet, plus whether you spend any of your time within the range of a Wi-Fi hotspot. If you want a SIM just to cover you on the odd occasion that you use your tablet away from home and need to continue to access your email, you certainly don't need to pay out extra for a 4G plan.

Some of the best SIM-only deals for tablets come from Three, which offers numerous plans including 15GB for £14 per month and 40GB for £18 per month. You can view those deals here.

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