The Cheapest Time to Fly Internationally is from February-March. Granted this one's a bit of a misnomer, because yearly price trends on international flights are typically dictated primarily by the high and low seasons of the destination abroad.
How far in advance should I book an international flight 2023?
“For international flights — [it's] four to 10 months.” If you're traveling during an off-peak season, you're going to want to look at airfares one to three months in advance for domestic flights, and two to eight months ahead of the flight for international trips.