Unlimited Mobile Broadband

With unlimited mobile broadband you gain unlimited internet access using mobile data, in either your home (with a static router) or when out and about (with a battery powered mobile Wi-Fi device or a dongle).

In either case, you can connect all your web-enabled gadgets to this, ensuring that your laptop and tablet for example can stay connected wherever you are. And while the most obvious use case is to bring internet with you, many people also benefit from 4G or 5G home broadband, as depending on where you are, this could be faster than conventional options.

In either case, Three has devices to suit, along with unlimited data plans, so you never need to worry about how much data you’re using. Below, you’ll find full details of those devices, along with more information on unlimited mobile broadband itself.

Is unlimited mobile broadband on Three really unlimited?

There are a few things to consider when looking at whether an unlimited data plan is truly unlimited, and we’ll address them all in the sections below.

Fair usage

Three has no fair usage restrictions for its unlimited data mobile broadband plans in the UK, other than that these should be for personal use. Many networks do have hidden fair usage caps on unlimited plans, so this is a major perk of Three.

Roaming

Three allows you to roam with its unlimited mobile broadband plans, so you can get all your devices connected to Wi-Fi even when outside the UK.   
However, on most plans roaming comes with a small daily charge, and there’s also a fair usage limit of 12GB per month when roaming – so you can’t actually use unlimited data when outside the UK.   
Speed restrictions

There are no speed restrictions on Three’s unlimited data mobile broadband plans, no matter how much data you use. So if you choose a 5G device then you can enjoy exceptionally high speeds – more on which below.

What speeds can I expect?

Three excels for speeds, and especially on 5G. According to a RootMetrics report from the second half of 2025, Three’s median 5G download speed is 198.3Mbps – which is the second highest on test. The same report also put its 95th percentile 5G download speed (meaning close to the highest) at 886.6Mbps, which was faster than any other network could manage.

Three’s average 5G download speed was also found to be higher than all rivals in a January 2026 Opensignal report, coming in at 187Mbps, so if you care about speed, then Three is the network to be on.

And if you get your device and you’re not happy with the speeds – or anything else about it – Three offers a 14-day money back guarantee on battery-powered mobile broadband devices, and a 30-day money back guarantee on home broadband.

What devices are available?

There are two distinct types of mobile broadband devices offered by Three, namely battery-powered mobile Wi-Fi routers, and home broadband routers.

Mobile Wi-Fi routers

A battery-powered 4G or 5G mobile Wi-Fi router is something you can slip into a bag and take with you wherever you go, allowing you to beam out a Wi-Fi network to all your portable gadgets, like laptops and tablets.   
This is ideal if you often find yourself out and about without access to Wi-Fi (or only with access to slow, unsecure, or expensive public Wi-Fi). However, battery-powered routers don’t always support a huge number of simultaneous connections, and of course you need to make sure the battery is charged.

Three 5G MiFi U50

The Three 5G MiFi U50 is Three’s fastest mobile broadband device, supporting 5G speeds of up to 1Gbps, and capable of getting up to 32 gadgets online.   
It’s compact, lightweight, and its 4,500mAh battery is good for up to eight hours of life, so you can stay connected during even long journeys.

Three 4G MiFi

The Three 4G MiFi is a portable, battery-powered device that supports speeds of up to 300Mbps and enables you to share internet with up 30 devices at the same time. It also supports both 2.4GHz and 5GHz Wi-Fi simultaneously.  It’s very small and light, so it’s ideal for carrying with you, it has a range of around 10 metres, and its battery lasts for up to 8 hours of use, or 300 hours of standby time.   
Home broadband routers

With a 4G or 5G home broadband router, you plug the router into a socket in your home (or anywhere else where you have access to sockets) and it will provide a permanent 4G or 5G-powered Wi-Fi connection to all your devices, making it an alternative to fibre broadband.

Three 5G Broadband

For home broadband, Three’s top option is the Three 5G Broadband, which is a 5G home broadband router, so it needs plugging in, but it supports extremely high speeds, theoretically reaching download speeds of up to 3.8Gbps (though Three’s network tops out at 1Gbps currently). Real world speeds are a lot lower, but still averaged 445Mbps in our Three 5G Broadband review.

The Three 5G Hub also supports 64 simultaneous device connections, 2.4GHz and 5GHz Wi-Fi, and has two Ethernet ports for wired connections, along with extension ports for external antennas, in case you need a signal boost.

Three 4G Broadband

Three 4G Home Broadband Hub is a mains-powered 4G home broadband router which supports download speeds of up to 600Mbps, allows for up to 64 simultaneous device connections, and includes Ethernet ports.

So it’s not as fast as the Three 5G Broadband, but if you only have a 4G signal at home then this is a top choice.

Can I buy an unlimited data SIM to use in my existing dongle/router?

Yes, Three also sells data-only SIMs on a choice of 1-month, 12-month, or 24-month contracts, and with up to unlimited data. Just purchase one of these and pop it into an existing device if you don’t also want new hardware.