Please be aware that Seoul and Taipei has multiple airports and that these results are for all airports serving the city.
The best month to fly between Seoul and Taipei is May and the most expensive month to fly is January. (Average prices, based on 361 datapoints.)
The best day to arrive at Seoul is Tuesday and it would be best to avoid Friday, as prices are on average 104.5% higher than on Tuesday. (Average prices, based on 361 datapoints.)
The cheapest airline flying from Seoul to Taipei is Asiana Airlines. They are 8% cheaper than EVA Air. (Average prices, based on 370 datapoints.)
The best time to fly is at around 10. (Average prices, based on 546 datapoints.)