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

Return flights

17 Sep - 22 Oct	Air China
01 Sep - 15 Oct	Air China
08 Sep - 13 Oct	Air China
02 Sep - 21 Oct	China Southern
20 Sep - 12 Oct	Air China
23 Sep - 14 Oct	Air China
23 Sep - 12 Oct	Air China
29 Sep - 28 Oct	Air China
29 Sep - 11 Oct	Air China
27 Sep - 12 Oct	Air China
01 Sep - 07 Sep	Shenzhen Airlines
05 Sep - 08 Sep	China Southern
01 Sep - 08 Sep	China Southern
02 Sep - 10 Sep	China Southern
03 Sep - 08 Sep	China Southern
03 Sep - 10 Sep	China Southern
02 Sep - 09 Sep	China Southern
08 Sep - 15 Sep	China Southern
20 Sep - 27 Sep	China Southern
04 Sep - 09 Sep	China Southern

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 $613

Return flights