AirHint found the following cheapest return flights from London (LCY) to Bangkok (BKK) in September 2026 (see full year).

Return flights

14 Sep - 22 Sep	KLM
14 Sep - 23 Sep	KLM
09 Sep - 17 Sep	KLM
15 Sep - 06 Oct	KLM
02 Sep - 16 Sep	KLM
02 Sep - 30 Sep	KLM
16 Sep - 23 Sep	KLM
09 Sep - 20 Sep	SWISS
08 Sep - 30 Sep	KLM
01 Sep - 30 Sep	KLM
01 Sep - 17 Sep	KLM
21 Sep - 05 Oct	KLM
21 Sep - 03 Oct	KLM
21 Sep - 12 Oct	KLM
17 Sep - 02 Oct	KLM
02 Sep - 04 Oct	KLM
18 Sep - 06 Oct	KLM
18 Sep - 03 Oct	KLM
18 Sep - 02 Oct	KLM
24 Sep - 08 Oct	KLM

Also check the deals for one-way flights from London to Bangkok 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 Bangkok in September from $775

Return flights