Please be aware that Jakarta and Seoul has multiple airports and that these results are for all airports serving the city.
The best month to fly between Jakarta and Seoul is November and the most expensive month to fly is October. (Average prices, based on 3350 datapoints.)
The best day to arrive at Jakarta is Wednesday and it would be best to avoid Saturday, as prices are on average 25.99% higher than on Wednesday. (Average prices, based on 3374 datapoints.)