The EU law abolishing roaming charges for people using mobile phones abroad comes into force on June 15.
According to the new rules, citizens traveling within the EU will be able to call, text and browse the internet on mobile devices at the same price they pay at home.
The European Commission said the end of roaming charges was one of the greatest successes of the EU.
However, a UK consumer group warned phone users could face “unexpected charges”.
Until now roaming, or connection, charges have been added to the cost of calls, texts and internet browsing when consumers from one EU country traveled to another and connected to a mobile network there.
In some cases, mobile users have faced huge bills if, for example, they have downloaded a movie.
The European Commission said in statement: “Each time a European citizen crossed an EU border, be it for holidays, work, studies or just for a day, they had to worry about using their mobile phones and a high phone bill from the roaming charges when they came home.”
It had been working hard over the last ten years to fix this “market failure”, it said.
“Eliminating roaming charges is one of the greatest and most tangible successes of the EU,” the Commission added.
The new legislation means travelers can use their regular data allowance anywhere in the EU.
In addition, different providers included different countries in their roaming territories, such as the Channel Islands and Switzerland.
Users should check the detail of their tariffs with their phone providers to avoid being caught out by surprise charges.
Regarding Brexit, it would be up to a future government to decide whether to have the EU price restrictions on roaming or not after the UK leaves the EU.
They are contained within a European regulation, not a directive, so they have not been incorporated into UK law.