The novelty of video calling may have done little to entice customers to the 3G networks that mobile operators paid so much for back in 2000, but the offer of ubiquitous fast internet access is proving more popular. Adverts for mobile 3G broadband are all over the place at the moment, but if the USB modems (or ‘dongles’) plastered across billboards and throughout newspapers all look the same, the deals from the different providers are anything but...

Just like mobile voice tariffs, mobile data tariffs vary enormously from provider to provider – and there’s more to it than just the monthly fee. As with home ISPs, the term ‘broadband’ is conveniently broad when it comes to mobile internet access and the variation in bandwidth offerings between the slowest and fastest download speeds available from the five UK mobile networks is considerable.

Mobile broadband basics

The standard 3G network provides download speeds up to 384Kbit/s and if all goes well, the UK will have full 3G coverage by the end of this year. Mobile operators are in the throes of upgrading their networks to HSPDA though, which will increase download speeds to a theoretical maximum of 7.2Mbit/s.

Not all mobile broadband provider offer the full 7.2Mbit/s HSDPA download speed though, and not even the respective quoted download speeds are guaranteed. HSDPA coverage is still patchy and a mobile broadband modem dynamically alters download speeds based on signal strength (and progressively drop to 3G, EDGE then GPRS speeds as the signal worsens). So, if you need a guaranteed download speed in a particular location, check the operators’ coverage maps first.  

Just remember that a fast download speed is really only necessary if you’re downloading large files – email and web browsing works just as well over the slower 384Kbit/s 3G connection. Vodafone has a handy online calculator that shows how many megabytes web pages, emails and streaming video can devour – it reckons 1000 web pages equates to 100Mb.

How much can you download?

You should also pay close attention to download limits. Most providers place a cap on how many gigabytes of data you can download each month – and don’t forget that you’re downloading data even when you’re just looking at web pages. The software supplied with an HSDPA modem will let you keep an eye on your data usage and what happens when you exceed it varies considerably.

T-Mobile and 3 operate a ‘fair use’ policy that will result in a notification if you regularly exceed its nominal monthly limit. 3 charges for any extra megabytes you download; T-Mobile initially opts for limiting your download for excess use, then it may invite regular excess downloaders to upgrade their tariff. Vodafone, on the other hand, charges £15 for every excess gigabyte, in all or part, that you download.

Finally, if you’re looking for a mobile broadband deal so you can browse the web abroad, pay close attention to roaming charges. Horror stories of people returning from an overseas trip to face bills of several thousand pounds are commonplace, all thanks to excessive roaming charges. Ofcom is paying close attention to mobile operators’ roaming charges though, so price-cuts are expected soon.

We've provided separate tables for each mobile operator's deals under the appropriate section, but all of the tables are available as a PDF download at the bottom of the last page.  

Postscript: Mobile broadband access comes courtesy of a small modem that plugs into a laptop's USB port. This has its own SIM card and, like a mobile phone, will only work when there's a strong enough signal. Most models also come with onboard flash memory that contains the necessary Windows drivers.

Lots of commenters on the Mobile Computer site have asked about using mobile broadband with a games console or other non-Windows device and the short answer is that you can't – directly. If you can connect the console to a PC via an Ethernet cable though, you can use Internet Connection Sharing to get it online using the modem.

Click on to page 2 to see the different mobile broadband deals compared.