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 August and the most expensive month to fly is January. (Average prices, based on 234 datapoints.)
The best day to arrive at Seoul is Tuesday and it would be best to avoid Monday, as prices are on average 76.13% higher than on Tuesday. (Average prices, based on 307 datapoints.)
The cheapest airline flying from Seoul to Taipei is EastarJet. They are 48% cheaper than EVA Air. (Average prices, based on 242 datapoints.)