Online Web Check-in
If you're traveling Ukraine economy premium class or business class, then they are allowing online check-in 14 days before scheduled departure. But, if you're traveling through economy class, then the online check-in time for scheduled flights is 48 hours and for charter flights 24 hours before your departure. However, the closing of both the flights is one the same time. All these classes booking can be done through UIA online web check-in or mobile app check-in.
Offline Check-in at Airport
You can also do Ukraine airline check-in at the airport desk by getting at the counter early. However, the check-in of baggage and boarding pass for most Ukraine international flights starts2 hours prior and ends 40 minutes before your flight departure. For New York-Kyiv and Bangkok-Kyiv, the airport check-in time starts at 4 hours and ends 1 hour before your scheduled flight departure.