Vodafone on Tuesday trumpeted the success of its Passport roaming service, which enables customers to take their domestic price plan abroad.

Vodafone said that data for June and July 2006 shows that Passport customers are paying around 50 per cent less per minute for their voice roaming calls compared to the average cost of roaming in a year ago. The average cost of a voice roaming call for these users is now below Eur0.45 (£0.30) per minute.

The operator said that 10 million subscribers – more than a third of all its roaming customers – have taken up the service since its launch in May 2005. An additional 150,000 customers are joining Vodafone Passport every week.

As a result, Vodafone claims it is on its way to reducing the average retail cost of roaming to all Vodafone customers by 40 per cent by April 2007, compared to the summer of 2005.

But while any reduction in retail roaming rates is good news for users, analysts believe the rapid uptake of Passport by customers fed-up with high roaming charges comes as no surprise.

Pauline Trotter, analyst with Ovum, commented that Vodafone’s 2007 Eur0.45 per minute target is unlikely to impress the European Commission, which is proposing a Eur0.36 per minute wholesale figure.

“And we suspect Vodafone’s reductions will be seen as only a small step in the right direction by its corporate customers,” Trotter said. “They will continue to argue that much bigger cuts in retail rates need to be made and that the cost of data roaming needs to be brought into the equation.”