In general when looking for the cheapest flight to Busan, try to book your flight during the month of March for the best deal.
In general, most flyers find the cheapest time to book a flight to Busan is about 60 days prior.
From most locations, the cheapest day to fly to Busan is Friday. Most users found that departing on a Sunday was most expensive.
Typically, cheap prices to Busan are most often found for afternoon flights. Cheap prices are less likely for noon flights.