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

Return flights

10 Sep - 17 Sep	LOT
16 Sep - 23 Sep	LOT
14 Sep - 21 Sep	Lufthansa
22 Sep - 01 Oct	Lufthansa
08 Sep - 15 Sep	Finnair
08 Sep - 30 Sep	Finnair
15 Sep - 22 Sep	Finnair
15 Sep - 23 Sep	Finnair
08 Sep - 22 Sep	Finnair
08 Sep - 16 Sep	Finnair
08 Sep - 23 Sep	Finnair
04 Sep - 01 Oct	Lufthansa
22 Sep - 02 Oct	Lufthansa
18 Sep - 28 Oct	Etihad Airways
17 Sep - 01 Oct	Lufthansa
24 Sep - 01 Oct	Vietnam Airlines
03 Sep - 01 Oct	Lufthansa
22 Sep - 15 Oct	Air China
03 Sep - 02 Oct	Lufthansa
23 Sep - 04 Oct	Air China

Also check the deals for one-way flights from Seoul to London 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 Seoul to London in September from $676

Return flights