Consumer group Which? has warned tablet owners against using data roaming services in the US and Europe, as 3G internet use can be 1,000 times more expensive than equivalent use in the UK.
Using the same 1GB of data on a tablet in France would theoretically cost Vodafone customers £200, rising to £1,311 for those on Three and a whopping £3,144 for those on Orange.
O2 does not allow customers to use tablets abroad at present, and T-Mobile customers are required to buy data boosters. These cost £1 for 3MB, £5 for 20MB and £10 for 50MB and last for 24 hours.
Using devices to carry out simple actions such as checking email can be a costly experience in Europe. Three charges £1.28 per megabyte and Orange £3.07 per megabyte, while Vodafone offers 50MB for £9.99.
Meanwhile, tablet owners are strongly discouraged from using tablets in the US as some networks charge as much as £8 per megabyte.
Vodafone offers the cheapest roaming deal, although it is still expensive at £600 for 1GB. This rises to £3,072 for Three customers, and to £7,680 for users on T-Mobile. However, customers on Orange could face an eye-watering bill of £8,192 for using just 1GB of data.
Which? did point out that mobile operators must send notifications to customers when data roaming in EU countries. However, there is no obligation on operators to do so when travelling outside the EU.
"With tablet data roaming costs often so astoundingly expensive, we'd like to see all operators do all they can to keep their customers informed of costs," said Ceri Stanaway, a Which? mobile services expert.
"Ideally, this would be - as a bare minimum - sending a notification to your tablet advising of costs, no matter where in the world you are, and making tablet roaming costs explicitly obvious on operator web sites."
In the meantime, tablet owners considering using their device for data-heavy tasks such as watching TV or video calling should stay clear of 3G data roaming and use free Wi-Fi access instead, Stanaway added.
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