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

Return flights

17 Sep - 11 Oct	China Eastern
17 Sep - 22 Oct	China Eastern
17 Sep - 26 Oct	China Eastern
16 Sep - 11 Oct	China Eastern
14 Sep - 14 Oct	China Eastern
23 Sep - 23 Oct	China Eastern
15 Sep - 15 Oct	China Eastern
22 Sep - 14 Oct	China Eastern
16 Sep - 13 Oct	China Eastern
16 Sep - 21 Oct	China Eastern
03 Sep - 08 Sep	Air China
03 Sep - 09 Sep	Air China
08 Sep - 29 Sep	Air China
22 Sep - 29 Sep	Air China
15 Sep - 29 Sep	Air China
04 Sep - 08 Sep	Air China
21 Sep - 29 Sep	Air China
14 Sep - 29 Sep	Air China
02 Sep - 09 Sep	Air China
02 Sep - 07 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 383€

Return flights