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

Return flights

22 Sep - 11 Oct	China Eastern
04 Sep - 11 Sep	China Eastern
24 Sep - 11 Oct	China Eastern
11 Sep - 16 Oct	Air China
02 Sep - 09 Sep	China Eastern
03 Sep - 09 Sep	China Eastern
02 Sep - 11 Sep	China Eastern
08 Sep - 13 Oct	China Eastern
01 Sep - 10 Sep	Air China
01 Sep - 04 Sep	Air China
18 Sep - 11 Oct	Air China
07 Sep - 10 Sep	Air China
02 Sep - 05 Sep	Air China
05 Sep - 10 Sep	Air China
01 Sep - 06 Sep	Air China
22 Sep - 15 Oct	Air China
22 Sep - 14 Oct	Air China
16 Sep - 11 Oct	Air China
18 Sep - 18 Oct	Air China
03 Sep - 15 Oct	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 $504

Return flights