Since its launch in October 2025, the European Union’s Entry-Exit System (EES) has been the subject of controversy. Whilst designed to streamline the procedure of entering and departing the EU for British travellers and other non-EU residents, there have been accounts of lengthy airport delays and confusion resulting from its rollout.

Whilst the EES won’t become fully operational until April 10, with numerous countries remaining inconsistent regarding whether they’re currently using it or not, it seems it’s already beginning to trip up holidaymakers who are baffled by a particular EU rule.

Digital nomad George Cremer, a software developer who created an app to assist British and other non-EU citizens in tracking their compliance with the new regulations, explained that the 90-day rule is already beginning to trip-up travellers. “Before EES, many miscalculations went unnoticed because border officials had to manually check passport stamps.

“Now every entry and exit is tracked digitally, and the system flags overstays automatically. So that 4,000 figure certainly includes a large number of people who genuinely believed they were compliant, some of whom have been in touch with us seeking guidance.”

The figure is derived from data supplied by eu-LISA, the EU agency accountable for overseeing the border control systems. George’s app, Schengen Simple, assists individuals in ensuring they comply with the 90/180-day rule, which restricts non-EU nationals such as Britons to 90 days of visa-free travel within the Schengen Area over a rolling 180-day period, reports the Mirror.

Whilst the 90/180-day rule appears straightforward, George told Majorca Daily News that there were three frequent errors that could trap travellers. The first problem is that people fail to understand it operates as a rolling window. He explained: “Most people think the 90 days work like a visa stamp: use up your days, leave, and the clock resets. It doesn’t.

“The 90/180 rule uses a rolling window, so every single day, the system looks back 180 days and counts how many of those you spent in the Schengen Area. A week in Portugal in January quietly eats into your summer allowance.”

He continued by clarifying that your days don’t reset upon leaving and re-entering, as the window continues rolling. While certain overseas residents practise ‘visa hopping’ where departing the country for a few days resets the period, this strategy proves ineffective in the EU.

George additionally noted that some travellers are caught out believing each nation tracks days separately. “All 29 Schengen countries share one 90-day pool. A weekend in Paris and a month in Spain are counted together.”

He also emphasised that the rule is not 90-days per half year, as some presume the 180-days represents a January to June/July to December division. However, it’s not. The 180 days count backwards from each individual day.

He also issued a warning for the upcoming busy travel season: “The other thing people miss is forward planning. With Easter and summer both approaching, travellers need to think about how their trips interact.

“Using up days over Easter could leave you short for a holiday you’ve already booked in July. We built Schengen Simple to work both ways, factoring in future plans so people can see their real allowance before they commit to a booking.”

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