Since 15 June 2017 roaming charges in the EU have been abolished allowing mobile customers to use their network provider’s allowance of minutes, text messages and data throughout the EU and the European Economic Area (EEA) without incurring additional charges.
The abolition of roaming charges will continue to apply in the UK until it leaves the EU.
A new House of Commons Library briefing paper, available here, looks at possible scenarios after Brexit.
The factsheets below, produced by the European Commission, explain the current pre-Brexit situation.
Roaming factsheet: TechnicalroamingfactsheetEN
Roam Like at Home FAQs: RoamLikeatHomeEN
However, as this BBC article explains, customers are still liable for extra charges if they exceed their contractually agreed data usage limits.