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

Return flights

01 Sep - 17 Sep	Lufthansa
26 Sep - 11 Oct	Lufthansa
15 Sep - 25 Sep	Lufthansa
23 Sep - 30 Sep	Lufthansa
01 Sep - 14 Sep	Lufthansa
06 Sep - 21 Sep	Lufthansa
14 Sep - 29 Sep	Lufthansa
19 Sep - 29 Sep	Lufthansa
19 Sep - 26 Sep	Lufthansa
03 Sep - 03 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 882€

Return flights