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Three SIM-only review

Three is the only mobile provider to offer unlimited data SIM-only plans, alongside unlimited texts and minutes. Three’s SIM-only prices start from £8 per month, and you can upgrade to 4G for free when the network rolls out to your area.

Three’s 3G and 4G data speeds are slower than those of rival networks, and its popular One Plan (with unlimited tethering) was stopped in 2014. However, it still offers generous SIM-only deals at competitive prices, so could Three be the provider for you? This review will help you decide.

Cable.co.uk overall rating

Three offers some of the UK's best SIM-only deals, with generous bundles of calls, texts and data at a reasonable price and free upgrades to 4G. Limited availability has let it down a little, but Three remains the only place to get all-you-can-eat data on 4G.

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Coverage & data speed



Three mobile covers 97% of UK homes and businesses. The primary service is 3G (the third generation of mobile broadband) so users can talk, text and use the internet in most parts of the country. Three’s 4G network, which launched in December 2013, is still in the rollout phase so coverage is not nearly as widespread as 3G. Three’s 4G network is currently smaller than the networks run by EE, O2 and Vodafone.

Three’s mobile download speeds averaged 7Mbps for 3G and 17Mbps for 4G according to Ofcom. In comparison to the industry averages of 6Mbps for 3G and 33Mbps for 4G, speeds are quite reasonable. Three’s 3G and 4G networks have lower latency, which is a measure of the time it takes to send information to the internet from your device. This is good news for anyone who likes to use video-calling software, such as Skype or Facetime.

3G coverage
4G coverage
Average 3G speed*
Average 4G speed*
Call allowance
200 minutes - unlimited
Text allowance
Data allowance
500MB - unlimited
Minimum contract
30 days
*According to Ofcom
Prices from
3G coverage 97%
4G coverage 91%
Average 3G speed* 7Mbps
Average 4G speed* 17Mbps
Call allowance 200 minutes - unlimited
Text allowance Unlimited
Data allowance 500MB - unlimited
Minimum contract 30 days
Prices from £8 per month
*According to Ofcom

Scroll horizontally for more information.

Data usage



Three is the only UK mobile provider to offer unlimited calls, texts and data on both 3G and 4G. This is a major perk for those who spend a lot of time online. Alternatively, you can choose from data limits of 500MB, 1GB, 2GB, 4GB, 8GB, 12GB or 30GB and Three will text you when you’re nearing your limit.

Using your phone as a personal wi-fi hotspot, known as tethering, is permitted on all Three’s SIM-only plans. Three used to offer unlimited tethering on the all-you-can-eat plan but tethering usage is now limited to 30GB per month. If you hit this limit, you can buy a Personal Hotspot Add-on. On all other plans, tethering is limited to your monthly data allowance. Three operates a traffic management policy called TrafficSense to prevent network congestion at peak times. It doesn’t limit the amount of data you can use, but time-sensitive activities, such as video streaming, are given priority from 3pm to midnight, while file sharing and tethering may be slowed down during the same period.

Calls & texts



All Three SIM-only plans include unlimited text messages, whereas picture and video messages cost 19.8p each. You can use a third party internet messaging service, such as iMessage or WhatsApp, which will use your data allowance instead (or wi-fi if you’re connected). Inclusive monthly call options include 200, 600 or unlimited minutes to standard UK landlines (starting 01, 02, 03), UK mobiles (any network) and your Three voicemail. If you reach your limit, you can either carry on making calls at 35p per minute, buy an add-on, or block any additional spending to keep your bill under control. All 0800 calls are free on Three SIM-only plans, but 084 and 087 numbers are charged at 5p per minute. Video calls cost 51.1p per minute, unless you are using a third party service such as Skype or FaceTime, which will use your data allowance or wi-fi instead. International call and text rates vary from country to country.

Extra features



Three offers some nice perks that differentiate it from other providers. First, Feel at Home is an exclusive feature that allows you to use your phone abroad at no extra cost. It operates in 16 countries and territories, including Australia, Austria, Denmark, Finland, France, Hong Kong, Indonesia, Israel, Italy, Macau, Norway, the Republic of Ireland, Sri Lanka, Sweden, Switzerland and the United States. Spain and New Zealand will be added later this year. Feel at Home includes calls and texts to UK numbers, as well as numbers within the country you are visiting, and also permits internet usage within your allowance. Tethering is not permitted abroad and if you have an all-you-can-eat data plan, usage is limited to 30GB. Feel at Home is intended for temporary travel and inclusive data roaming, calls and texts may be suspended if used in a single destination for more than two consecutive months.

Three also offers unlimited free wi-fi in London Underground stations through a partnership with Virgin Media. Commuters and visitors can get online in entrance halls, escalators and platforms in 130 Tube stations, but not when travelling between stations.

Value for money



Three offers a wide selection of SIM plans to suit a range of budgets, starting from £8 per month. Three gives at least 500MB of data, 200 minutes and unlimited texts with every plan. The offer of unlimited data is a major boon and good value from £26 per month. Three also offers 4G at the same cost as 3G, which is a bonus as you can upgrade for free when the network rolls out to your area (providing your phone is 4G-ready).

With the generous bundles and useful extras, Three undoubtedly offers good value for money. However, the slower internet speeds can’t be ignored and customer satisfaction has slipped a little in recent years. Three scored below average in the latest Ofcom report but it wasn’t terrible with an overall satisfaction score of 69% compared to industry average of 72%.

Overall Rating


Three is a solid choice for your SIM-only deal, with a wide choice of plans on short and long-term contracts for a range of budgets. The main attractions are the coveted unlimited data for those of us who live online, 4G at no extra cost, and free use of your phone abroad in many destinations. It’s not all rosy however; you may not be able to get 4G if you’re outside a major town or city, and your internet speed could be slower than that offered by rival networks.

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