Please be aware that Tokyo and Seoul has multiple airports and that these results are for all airports serving the city.
The best month to fly between Tokyo and Seoul is May and the most expensive month to fly is March. (Average prices, based on 565 datapoints.)
The best day to arrive at Tokyo is Thursday and it would be best to avoid Sunday, as prices are on average 51.13% higher than on Thursday. (Average prices, based on 540 datapoints.)
The cheapest airline flying from Tokyo to Seoul is Peach Aviation. They are 87% cheaper than All Nippon Airways. (Average prices, based on 585 datapoints.)
The best time to fly is at around 10. (Average prices, based on 884 datapoints.)