Please be aware that Osaka and Seoul has multiple airports and that these results are for all airports serving the city.
The best month to fly between Osaka and Seoul is August and the most expensive month to fly is July. (Average prices, based on 363 datapoints.)
The best day to arrive at Osaka is Thursday and it would be best to avoid Monday, as prices are on average 176.37% higher than on Thursday. (Average prices, based on 363 datapoints.)
The best time to fly is at around 10. (Average prices, based on 468 datapoints.)