Plane tickets usually don’t get cheaper closer to the departure date. Even these reasonably priced flights in the low season sell out quite far ahead of the date of travel. It pays to book your ticket well in advance, as it will give you a good range of flight times and seat selection choices. The best time to book flights to Korea can vary among airlines but the golden time usually falls between 2 months and 6 months before the departure. So, January is the best time to book flights if you want to visit South Korea during the summer.