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

Return flights

10 Sep - 17 Sep	Air China
19 Sep - 01 Oct	Air China
13 Sep - 27 Sep	Air China
09 Sep - 16 Sep	Air China
06 Sep - 07 Sep	Air China
24 Sep - 30 Sep	China Southern
06 Sep - 10 Sep	Japan Airlines
25 Sep - 28 Sep	Air China
28 Sep - 03 Oct	Air China
14 Sep - 28 Sep	Air China
26 Sep - 12 Oct	Air China
13 Sep - 20 Sep	Japan Airlines
21 Sep - 30 Sep	Japan Airlines
30 Sep - 13 Oct	Japan Airlines
30 Sep - 12 Oct	Japan Airlines
21 Sep - 21 Oct	Japan Airlines
26 Sep - 01 Oct	Japan Airlines
29 Sep - 13 Oct	Japan Airlines
26 Sep - 05 Oct	Japan Airlines
28 Sep - 05 Oct	Japan Airlines

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 $880

Return flights