Despite such efforts, avoiding high roaming charges requires attention and vigilance.
Other iPhone users have felt the sting of high roaming charges with their iPhone, too.
He said that high roaming prices in Europe, especially for downloading data, reflected the operators' profit expectations, not the true costs of service.
Bill shocks mostly occur when users take their phone abroad, and are unaware of the higher roaming data charges they face.
In recent speeches, Mrs. Kroes has been critical of Europe's mobile operators, saying she saw no justification for the high roaming charges imposed on consumers, which has also deterred cross-border business development.
When a digital signal is too weak or the system is too busy, some cellphones switch to backup analog networks, which typically carry high roaming charges for some users and make features such as caller ID or text messaging unusable.
"I am fully aware, both as a policymaker and as a consumer, of the impact that high roaming charges have on EU citizens and on the competitiveness of our industry," Viviane Reding, the EU's information society and media commissioner, said.
Many customers have faced bills for thousands of pounds after falling foul of current high roaming charges.
Typically these offer the ability to make international calls over 3G or Wi-Fi on a smartphone in a bid to circumvent existing mobile telcos who generate large revenues based on high roaming costs.
Another example is the use of a cellular link of the national operator abroad (e.g., on an international train), which yields high roaming costs and is preferably avoided by switching to a cellular link of an operator of the visited country.
