If you are going abroad with your smartphone and don’t want to come home to a large and unexpected bill, you should turn off data roaming – even if you don’t use your phone and have it switched off your whole holiday, you could still get a nasty surprise so take precautions and turn off roaming data before you travel.
Here’s how:
On a Samsung Galaxy:
On an iPhone:
On a Blackberry:
There are also plenty of offline travel apps that don't need a data connection, this help gives you all the information you need without costing a fortune.