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

Return flights

06 Sep - 09 Sep	Saudia
30 Sep - 30 Sep	Saudia
30 Sep - 21 Oct	Saudia
27 Sep - 21 Oct	Saudia
09 Sep - 14 Oct	Saudia
23 Sep - 30 Sep	Saudia
20 Sep - 30 Sep	Saudia
20 Sep - 23 Sep	Saudia
20 Sep - 28 Sep	Saudia
09 Sep - 14 Sep	Saudia
16 Sep - 28 Sep	Saudia
11 Sep - 11 Sep	Saudia
19 Sep - 21 Sep	Saudia
26 Sep - 19 Oct	Saudia
26 Sep - 21 Oct	Saudia
29 Sep - 21 Oct	Saudia
30 Sep - 13 Oct	Saudia
22 Sep - 02 Oct	Saudia
29 Sep - 11 Oct	Malaysia Airlines
26 Sep - 20 Oct	Saudia

Also check the deals for one-way flights from Bangkok 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 Bangkok to London in September from $734

Return flights