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

Return flights

05 Sep - 10 Sep	Air China
17 Sep - 28 Sep	Air China
08 Sep - 19 Sep	Air China
10 Sep - 21 Sep	Air China
03 Sep - 10 Sep	Air China
03 Sep - 08 Sep	Air China
01 Sep - 08 Sep	Air China
20 Sep - 27 Sep	China Eastern
21 Sep - 27 Sep	Japan Airlines
25 Sep - 01 Oct	Japan Airlines
24 Sep - 01 Oct	Japan Airlines
28 Sep - 05 Oct	Japan Airlines
28 Sep - 01 Oct	Japan Airlines
01 Sep - 05 Sep	Japan Airlines
26 Sep - 05 Oct	Japan Airlines
28 Sep - 07 Oct	Japan Airlines
24 Sep - 08 Oct	Japan Airlines
23 Sep - 05 Oct	Japan Airlines
28 Sep - 08 Oct	Japan Airlines
28 Sep - 12 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 685€

Return flights