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

Return flights

17 Sep - 30 Sep	Lufthansa
29 Sep - 03 Oct	China Eastern
29 Sep - 04 Oct	China Eastern
23 Sep - 01 Oct	LOT
17 Sep - 24 Sep	SWISS
28 Sep - 02 Oct	China Eastern
19 Sep - 30 Sep	Lufthansa
18 Sep - 30 Sep	Air France
24 Sep - 30 Sep	Air France
25 Sep - 29 Sep	T'way Air
28 Sep - 03 Oct	China Eastern
18 Sep - 23 Sep	Air France
18 Sep - 20 Oct	T'way Air
17 Sep - 05 Oct	SWISS
17 Sep - 29 Sep	SWISS
24 Sep - 02 Oct	Air France
19 Sep - 24 Sep	Lufthansa
23 Sep - 30 Sep	Lufthansa
19 Sep - 01 Oct	Air France
19 Sep - 02 Oct	Air France

Also check the deals for one-way flights from Seoul to Lisbon 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 Seoul to Lisbon in September from $809

Return flights