Please be aware that Seoul and Jakarta has multiple airports and that these results are for all airports serving the city.
The best month to fly between Seoul and Jakarta is October and the most expensive month to fly is February. (Average prices, based on 1501 datapoints.)
The best day to arrive at Seoul is Monday and it would be best to avoid Saturday, as prices are on average 16.58% higher than on Monday. (Average prices, based on 1501 datapoints.)
The cheapest airline flying from Seoul to Jakarta is Asiana Airlines. They are 13% cheaper than Korean Air. (Average prices, based on 1504 datapoints.)