More and more of us are using our mobile phones abroad, whether we're on business or for pleasure.
Declan explains how roaming calls are calculated
But some mobile customers are getting a nasty shock when they return home.
The high cost of calls is leaving many with very expensive bills.
Declan explained how the charges work, and how to avoid them
Declan said British phone users pay some of the highest roaming charges in Europe.
And that's something Europe's regulators want to change
We heard from one traveller who was shocked by the cost of his bill, even though he thought he'd found a good deal.
And Declan spoke to Anthony Ball from a website called Onecompare.com that has some information about how to economise on the cost of calls when abroad.
Watch both our reports again from the link to the right