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

Return flights

16 Sep - 08 Oct	SWISS
17 Sep - 24 Sep	KLM
10 Sep - 23 Sep	KLM
16 Sep - 23 Sep	KLM
16 Sep - 24 Sep	KLM
04 Sep - 17 Sep	KLM
10 Sep - 17 Sep	KLM
01 Sep - 17 Sep	KLM
18 Sep - 24 Sep	KLM
02 Sep - 17 Sep	KLM
07 Sep - 17 Sep	KLM
30 Sep - 16 Oct	KLM
29 Sep - 14 Oct	KLM
29 Sep - 09 Oct	KLM
17 Sep - 06 Oct	KLM
16 Sep - 07 Oct	KLM
09 Sep - 15 Oct	SWISS
23 Sep - 15 Oct	SWISS
30 Sep - 15 Oct	SWISS
22 Sep - 22 Oct	KLM

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.

Book a cheap hotel in Seoul

Cheap car rent in Seoul

Cheapest return flights from London to Seoul in September from $747

Return flights