From November, the approximate 1.4 billion people who visit the Schengen area each year without having to obtain a short-stay visa, will have to apply online for authorisation to enter the free movement zone.
Applications for the authorisation, called the European Travel Information and Authorisation System (ETIAS), will be submittable via a website.
Travellers applying for ETIAS are required to upload a scan of their passport and answer a list of questions. The application process is designed to take around 10 minutes.
The ETIAS has been in development since 2016, and is intended to provide border security forces with advanced awareness of who is visiting Schengen in the near future.
The authorisation system was originally due to come into effect in May 2023, but was postponed to November due to delays from contractors.
Croatia became a member of both Schengen and the Euro on 1 January this year.