AirHint found the following cheapest return flights from Cologne (CGN) to Seoul (ICN) in September 2025 (see full year).

Return flights

02 Sep - 15 Sep	Ryanair
03 Sep - 19 Sep	Turkish Airlines
01 Sep - 12 Sep	Turkish Airlines
08 Sep - 15 Sep	Ryanair
15 Sep - 21 Sep	Eurowings
30 Sep - 07 Oct	Ryanair
02 Sep - 17 Sep	Eurowings
01 Sep - 14 Sep	Eurowings
04 Sep - 19 Sep	Turkish Airlines
02 Sep - 11 Sep	Eurowings
01 Sep - 17 Sep	Lufthansa
23 Sep - 10 Oct	Turkish Airlines
22 Sep - 10 Oct	Turkish Airlines

Also check the deals for one-way flights from Cologne to Seoul in September.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from Cologne to Seoul in September from 667€

Return flights