European Union roaming regulations

The Roaming Regulation 2022 ((EU) 2022/612) bans roaming charges (Eurotariff) within the European Economic Area (EEA), which consists of the member states of the European Union, Iceland, Liechtenstein and Norway along with two EU candidate states Moldova and Ukraine. This regulates both the charges mobile network operator can impose on its subscribers for using telephone and data services outside of the network's member state, and the wholesale rates networks can charge each other to allow their subscribers access to each other's networks.

Source: Wikipedia — European Union roaming regulations (CC BY-SA 4.0)