The best pricing can be found in the month of November. Prices to Pusan from Washington Dulles Intl average $1,150. You can even find prices in November for less than $1,150, as users have found deals to Pusan from as low as $570. The month of August appears to be one of the more expensive times to travel to Pusan from Washington Dulles Intl. Flying in the targeted month can save you up to 40%.