Mobile operator 3 has scrapped roaming charges in another five countries, allowing customers to use data while on holiday in a total of 16.
CEO David Dyson said 3 had now axed roaming charges in France, Switzerland, Norway, Finland and Israel.
He added: "The big challenge in terms of rolling out more countries is the amount of money that we have to pay to the overseas operators when our customers go on to their networks.
"In the countries where we aren't able currently to make the offer to our customers, it's because the charges are still very high and therefore we're not in a position to be able to allow our customers to roam at no extra cost in those countries.
"But we are working hard to negotiate rates with them and as soon as we do get lower fees, than we will pass those fees back to our customers."
3, along with EE, Virgin Media and Vodafone, have all pledged their support to the Government to scrap roaming charges altogether by 2016.