Irish consumers using their mobile phones in Europe will see reductions in their bills from today on.
Further caps are coming into effect on roaming, or connection, charges within all 28 countries of the European Union.
From June next year, roaming charges in the EU will be abolished completely.
Experts say those making mobile calls, downloading data or texting will save millions of euro in charges following the latest changes.
However, Micheal Kilcoyne of the Consumer Association says phone companies here still need to do more.
He said: "Of course it was only really implemented as a result of pressure from the EU Commission.
"Yes, it's to be welcomed but these mobile companies and providers of mobile data have made a fortune on consumers, and in my view should reduce their prices even further."