Advance Passenger Information (API) is now a standard requirement for travel to nearly every major country in 2026. Governments use this data (full name, passport number, and flight details) to screen passengers before they even arrive at the airport. Key countries that mandate API include the USA, UK, Canada, Australia, Japan, Mainland China, India, and South Korea. In 2026, the ETIAS (European Travel Information and Authorisation System) is also in full effect, requiring travelers from visa-exempt countries (like the US and UK) to provide detailed personal and travel information before entering the Schengen Area in Europe. Other countries like Mexico, Vietnam, Thailand, and Indonesia also require airlines to collect and transmit this data. Most airlines now integrate this into the online check-in process; if you do not provide your API at least a few hours before departure, the airline may be legally blocked from issuing you a boarding pass or allowing you to board the aircraft.