Telecoms giant O2 has ramped up the price of using your phone when travelling outside of Europe, with customers expected to pay up to 140% more from the end of November.
O2 pay-monthly customers are now being charged up to twice as much to use their phone in places such as the US, Canada and Asia Pacific as they were before the price hike kicked in.
Customers travelling in the US or Canada will experience the highest increases, with the cost of receiving a call shooting up from 39p to 90p a minute. The cost of making calls has risen by 20p to £1.10, while sending a text will now set you back 40p, up from 25p.
In addition, the cost of making a call from the Asia-Pacific region has increased by 20p per minute, while making calls in the rest of the world will be £1.50 per minute, up from £1.20.
O2 has been blamed for raising these charges to offset the effect of the European Commission's cap on roaming charges that came into effect in July this year.
"O2 is doing this simply because it can. The roaming market is now regulated within European mobile operators, but there is no cross-continental regulation or body with jurisdiction," says Tomas Mendoza, managing director of Tep Wireless, a pocket wi-fi provider.
However, a spokesperson from O2 denied the accusations. "This is the first time we have changed these prices in more than five years and we've ensured they remain competitive," he says.
If you're worried about high mobile charges when abroad, make the most of free apps such as Skype that use wi-fi to make free calls and send free instant messages.