More than five million Britons have received a roaming alert or been charged despite never leaving the UK, research suggests
Millions of British holidaymakers choosing to stay in the UK this summer face the risk of unexpected mobile phone charges without ever crossing the border, new research has revealed.
The phenomenon, dubbed "phantom roaming," occurs when smartphones automatically latch onto foreign networks that broadcast stronger signals than domestic ones, particularly in coastal regions.
Over five million people in the UK have been hit with a roaming alert or charge despite not having left the country, according to USwitch.
Kent and Sussex represent the highest-risk areas, where devices can inadvertently connect to French mobile towers across the English Channel.
Near Dover and Folkestone, the stretch of water separating Britain from France measures just 21 miles, allowing overseas signals to reach UK shores with ease.
Those travelling to Northern Ireland also face similar issues, with phones potentially picking up Irish networks near the border.
Whether staycationers face additional costs depends entirely on their mobile provider.
BT/EE and Vodafone/Three are the only major UK networks that do not offer EU roaming as part of their standard packages.
Customers with these providers could be charged a flat daily fee, typically ranging from £2 to £3, simply for their phone connecting to a continental signal.
In contrast, O2, Sky Mobile, Tesco Mobile, iD Mobile, giffgaff, SMARTY, Virgin Media and Talkmobile all bundle European roaming into their plans at no extra cost.
For subscribers on these networks, an accidental connection to a French or Irish tower should not result in any surprise fees.
The Uswitch survey revealed that three quarters of respondents either believed phantom roaming was impossible or had no idea it could occur at all.
Paul Williams, a commuter from Deal in Kent, described his daily experience with the issue: "Every day on my commute from Deal in Kent, my train runs along the White Cliffs, and my phone often picks up a French mobile signal. I regularly get a text welcoming me to France, even though I'm still in the UK."
He added: "Fortunately, I always keep roaming switched off, so I've never been caught out by unexpected charges.
"But it shows just how easy it would be for someone to unknowingly connect to an overseas network and end up with a costly roaming bill without ever leaving the country."
Simrat Sharma, mobiles expert at Uswitch, advised: "Switching it off and manually selecting your UK network before you head to a coastal or border area is the simplest way to stay protected, and it takes two minutes."
She recommended that customers also set spending caps or block data roaming entirely through their provider's app before travelling to affected regions.
For those who discover unexpected charges on their bill, Sharma urged immediate action: "If you do get caught out, contact your provider straight away,some will waive the charges, but it's not guaranteed, so the sooner you flag it, the better."
Consumer expert Helen Dewdney noted that customers can escalate disputes to CISAS or the Communications Ombudsman if providers refuse to remove charges they consider unfair.
