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 1588 datapoints.)
The best day to arrive at Seoul is Thursday and it would be best to avoid Sunday, as prices are on average 18.71% higher than on Thursday. (Average prices, based on 1576 datapoints.)