Holidaymakers are being warned that using mobile phones on ferries could be more expensive than they think.
The service used by major ferry operators, including Irish Ferries and Stena Line, is not subject to the new maximum roaming charges imposed by the European Commission.
The Norwegian company behind the service, Maritime Communications Partners, says that customer charges are determined by their mobile operators.
However, it says the cost of the satellite technology used makes it more expensive to offer mobile coverage in open waters.
