has already warned carriers that prices for so-called data roaming have to fall by the summer, or else--a message she will likely repeat at the industry's main trade show, the in Barcelona, which starts Monday.
"Industry claims they don't need regulation. I say, get it done," Reding said last month.
The 27-nation EU adopted a proposal from Reding last year tooutside a person's home country, but the proposal did not include data and text messages.
A study by the European Regulators Group published in January found that transferring 1 megabyte of data--the size of a large spreadsheet--while roaming on average cost 5.24 euros ($7.59) in the EU in the third quarter of last year.
By contrast, several operators offer domestic data plans that include a gigabyte of data, or roughly a thousand megabytes, for less than 50 euros.
Telecommunications consultant John Strand said the margins on data roaming were "sky high," but he estimated that it only represented about 2 percent to 4 percent of an operator's revenue.
Vodafone, the world's largest mobile phone company by revenue, said last month that data roaming was less than 1 percent of revenue.
The industry argues that theis still young and that operators are already cutting prices.
Vodafone said on Friday that it would reduce prices by up to 45 percent on its monthly data-roaming charge for European business travelers to make it cheaper to use laptop computers wirelessly when abroad.
The carrier will charge a maximum of 60 euros ($86.93) per month for 150 megabytes of data.
KPN, 3 Group, and Polish operator Play said this week that they had agreed to cut the price they charge each other for 1 megabyte of data roaming to 0.25 euros (36 cents), a quarter of the lowest currently available wholesale rate in Europe.
Spanish firm Telefonica has also cut its roaming-data fees in the past month.
Operators may be able to at least partially recoup the profits they forgo by increased usage.
Strand said there was no exact data on whether consumers had made more calls abroad after voice-roaming prices were cut, though "many operators tell me that traffic is going up and (that) they look forward to the next holiday season."