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

Return flights

25 Sep - 13 Oct	Hainan Airlines
14 Sep - 27 Sep	Air India
01 Sep - 16 Sep	Air India
09 Sep - 23 Sep	Air India
14 Sep - 28 Sep	Air India
14 Sep - 20 Sep	Air India
01 Sep - 29 Sep	Air India
15 Sep - 20 Sep	Air India
16 Sep - 20 Sep	Air India
17 Sep - 20 Sep	Air India
08 Sep - 13 Sep	Air India
21 Sep - 07 Oct	Air India
21 Sep - 18 Oct	Air India
23 Sep - 07 Oct	Air India
14 Sep - 05 Oct	Air India
16 Sep - 07 Oct	Air India
23 Sep - 06 Oct	Air India
16 Sep - 04 Oct	Air India
07 Sep - 05 Oct	Air India
22 Sep - 06 Oct	Air India

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.

Book a cheap hotel in Bangkok

Cheap car rent in Bangkok

Cheapest return flights from London to Bangkok in September from 461€

Return flights