Mobile networks must be more explicit about roaming charges after UK consumers spent £539m last year on ‘unexpected’ fees for mobile usage while abroad.

Regulator Ofcom says one in five adults are not aware that they will be charged for data, calls and texts when leaving the country.

EE, Three and Vodafone are among the major mobile networks that reintroduced roaming charges following Brexit.

Only O2 currently allows customers to use their mobile plans in the EU, though it does have a 25GB monthly “fair use” limit.

Ofcom now wants mobile networks to be clearer about roaming charges outside of the UK.

It says new rules will be drafted and potentially introduced in 2024.

Providers will then have six months to prepare for the changes.

Uswitch also “strongly supports” the recommendations by Ofcom.

The comparison site says UK consumers currently have little to no regulatory protections regarding data plans.

Uswtch’s Ernest Doku noted: “Roaming costs can now be incredibly expensive, and consumers have been left exposed at a time when a large unexpected bill could have severe consequences.”

Mobile customers are currently spending around £2 per day for roaming, which has racked up costs of £500m+ during the last twelve months.

Ofcom also wants new rules in place for “inadvertent roaming” for customers in the UK who live close to borders in the Republic of Ireland and France and accidentally connect to overseas networks.

Ofcom’s Cristina Luna-Estbena said the new proposals would ensure customers are no longer “left in the dark” and will have all the info they need to manage their finances.