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

Return flights

16 Sep - 23 Sep	Air China
15 Sep - 22 Sep	China Eastern
01 Sep - 05 Sep	Air China
17 Sep - 24 Sep	Air China
09 Sep - 23 Sep	Air China
15 Sep - 23 Sep	Air China
12 Sep - 20 Sep	Air China
02 Sep - 09 Sep	Air China
15 Sep - 24 Sep	Air China
01 Sep - 13 Sep	Air China
18 Sep - 14 Oct	Air China
19 Sep - 14 Oct	Air China
25 Sep - 14 Oct	Air China
28 Sep - 14 Oct	Air China
28 Sep - 15 Oct	Air China
28 Sep - 25 Oct	Air China
23 Sep - 01 Oct	Air China
26 Sep - 03 Oct	Air China
25 Sep - 01 Oct	Air China
26 Sep - 05 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 $835

Return flights