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 July and the most expensive month to fly is January. (Average prices, based on 360 datapoints.)
The best day to arrive at Seoul is Tuesday and it would be best to avoid Monday, as prices are on average 70.82% higher than on Tuesday. (Average prices, based on 210 datapoints.)
The cheapest airline flying from Seoul to Taipei is Tigerair Taiwan. They are 53% cheaper than EVA Air. (Average prices, based on 376 datapoints.)
The best time to fly is at around 10. (Average prices, based on 590 datapoints.)