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

Return flights

22 Sep - 13 Oct	China Southern
08 Sep - 13 Oct	China Southern
22 Sep - 22 Oct	China Southern
09 Sep - 14 Oct	Air China
10 Sep - 15 Oct	Air China
15 Sep - 15 Oct	Air China
29 Sep - 10 Oct	China Eastern
24 Sep - 13 Oct	Air China
24 Sep - 12 Oct	Air China
19 Sep - 11 Oct	Air China
03 Sep - 10 Sep	Air China
08 Sep - 15 Sep	China Southern
09 Sep - 17 Sep	Wizz Air Malta
08 Sep - 16 Sep	Air China
10 Sep - 18 Sep	Air China
12 Sep - 21 Sep	China Southern
12 Sep - 16 Sep	China Southern
11 Sep - 16 Sep	Air China
10 Sep - 17 Sep	Air China
10 Sep - 21 Sep	Air China

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 $527

Return flights