At the moment, there are zero airlines flying to Seoul. Go through the results to find the right flights for you – you can adjust the filters to see find even more flights to Seoul.
If you can't find a flight time that suits you, why not look at flying out from a different airport?
The distance between George Best Belfast City Airport to Seoul is 8819 km. You can see the various flight times in the results.
You can also search by month, which will reveal the cheapest time of the week to fly.