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

Return flights

22 Sep - 10 Oct	China Southern
24 Sep - 26 Oct	China Southern
15 Sep - 13 Oct	China Southern
21 Sep - 19 Oct	China Southern
19 Sep - 13 Oct	China Southern
24 Sep - 10 Oct	China Southern
23 Sep - 14 Oct	China Southern
25 Sep - 26 Oct	China Southern
16 Sep - 16 Oct	China Southern
25 Sep - 16 Oct	China Southern
11 Sep - 15 Sep	Lufthansa
10 Sep - 15 Sep	Lufthansa
09 Sep - 15 Sep	Lufthansa
08 Sep - 16 Sep	Lufthansa
07 Sep - 15 Sep	SWISS
11 Sep - 17 Sep	Lufthansa
11 Sep - 14 Sep	Lufthansa
02 Sep - 15 Sep	SWISS
08 Sep - 15 Sep	Lufthansa
01 Sep - 15 Sep	SWISS

Also check the deals for one-way flights from London 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 London to Seoul in September from $583

Return flights