Vodafone is targeting users of Wi-Fi services with a new international flat-rate mobile data fee.

For €12 (US$16), Vodafone customers will be able to connect to the Internet with mobile data card-enabled notebooks and surf the web for 24 hours, the company said.

"In terms of both price and reach, this is a very competitive offering to Wi-Fi," said Friedrich Joussen, CEO of Vodafone D2.

The new flat-rate mobile data offer, to launch 1 July, will be initially available to customers in Austria, Belgium, Denmark, Germany, Greece, Finland, France, Ireland, Italy, the Netherlands and the U.K.

Vodafone plans to sign up 32 roaming partners for the service by the end of next month.

Customers will pay the same fee whether they connect in their home market and when roaming on a Vodafone subsidiary network. Roaming customers, however, have a download restriction of 50M bytes during the 24-hour period.

Various billing options are possible, including prepaid card, credit card and phone bill.

As for roaming fees for voice calls, Joussen said he prefers a "benchmark" price instead of a set price applicable to all carriers. "One size doesn't fit all," he said.

Joussen warned of regulation in the mobile phone market, which he said is among the most competitive sectors in the world.

The European Commission has threatened to cap prices for roaming services. National governments remain divided, but Germany, which currently holds the rotating presidency of the European Union, has proposed capping the price of making a call abroad at €0.50 and the price of receiving a call while abroad at €0.25.