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Three's unlimited data SIM: now 6 months half price at £10 a month

Three phone and SIM card

The retailers featured on this page may compensate us when our readers follow links to their websites and make a purchase. More

You can now get Three's unlimited data SIM only plan half price for 6 months. We look at how the offer works and any restrictions on the data. SIM Sherpa is your trusty guide. Last updated: June 26th 2019.

What's the deal?

Three unlimited data SIM only

Unlimited everything, half price for six months  (4.5/5)

Three SIM card

It's unlimited data. And it's priced at £10 a month for your first 6 months, then £20 a month. That averages out to £17.50 a month over the course of the 24-month contract.

But remember if you stay after 24 months, that average will go up as you're paying full price. Three haven't yet provided a fixed end date for the offer.

You also get Three's usual benefits of 99% 4G population coverage, inclusive roaming and perks like free easyJet upgrades and their daily rewards app, Wuntu.

Useful link: Read full benefits below

4G data
£20 a month
on a 24-month contract

£10 for first 6 months

Get the deal
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What's good about it?

It's genuinely unlimited data - and that's pretty rare

Three offer banner

On a 24-month contractSee full offer

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If you've ever put your phone down because you're worried about going over you data usage limits, Three's unlimited data SIM puts an end to that. You're free to use as much as you like in the UK at no extra cost.

And you're not limited by any sneaky traffic management or throttling rules when you use it in this country either. Others sometimes promise no data caps but then slow you down to stop you using too much.

You can also use it for tethering (personal hotspot), which is where you connect tablets or laptops to your phone so they can access internet anywhere you have mobile signal. That's unlimited in the UK too.

The only restrictions come when you're using your SIM abroad. There, you won't be able to use tethering, a monthly cap of up to 19GB applies (depending where you are) and Three reserve the right to slow down your connection while roaming.

Useful link: Three's terms and conditions

Three's network offers good 4G coverage and speeds

Three's network map

Make sure you'll be able to use unlimited dataCheck Three's coverage

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It's true that Three aren't the UK's largest network but they now put their 4G coverage as reaching 99% of the population in the places where they live. There's still work to do in rural locations.

We'd always recommend checking any network's coverage before you sign up. Use Three's official network map here to do so. Be sure to look not just at home but anywhere you'll be using your phone.

Over 4G, we'd expect Three customers to get download speeds of around 20 Mbps on average, which currently puts them in joint second with Vodafone behind EE.

This is a healthy score that is similar to what many will be getting home over non-fibre broadband. It'll support smooth video and audio streaming and let you browse the general internet

Useful link: Check Three signal in your area

The £17.50 average monthly cost beats Three's competition

SMARTY SIM only planSMARTY Unlimited data offer banner

SMARTY uses Three's networkSee full deal

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It's Three's best price we see for unlimited data nowadays

Three's Black Friday offer banner

Previous best was £20 a month straight upSee new offers

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We monitor Three and other mobile networks' offers constantly. A £20 price has been available four times in 2018/19 on the 12-month SIM, most recently until 16th May.

The 12-month price is now at £20 price, a low price historically. Three have previously charged £32, £29 and £27 for the plan in the last years.

Three's 24-month SIMs have only just launched. And this deal has been priced at £22 a month and £20 a month previously, so the current full price is a record best.

Useful link: See Three's SIM only deals page

SIM Sherpa can help you find your next SIM only deal

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