Usually, they will ask you to provide these details when you book your flight or check in. Contact your airline if you have any questions about API requirements. Your information will be taken either at the time of booking or by an automated passport reader during check-in.

You can submit your Advance Passenger Information (API or APIS) through your airline’s website or mobile app, usually under the "Manage My Booking" or "Check-In" section. Most international airlines in 2026 require this data—which includes your full name, passport number, expiration date, and country of residence—at least 72 hours before departure. If you haven't done it by the time online check-in opens (24 hours before flight), the system will force you to enter it before issuing a boarding pass. In many modern airports, you can also scan your passport at a self-service kiosk to update this info on the day of travel. It is a peer-to-peer "best practice" to do this as early as possible, especially for flights to the U.S. or U.K., as the data is screened by government agencies like the TSA; if there is a mismatch or missing info, you may be flagged for extra screening or denied boarding at the gate.