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

Return flights

23 Sep - 08 Oct	Air India
09 Sep - 23 Sep	Air India
02 Sep - 28 Sep	Air India
18 Sep - 28 Sep	Air India
23 Sep - 30 Sep	Air India
01 Sep - 31 Oct	Air India
25 Sep - 06 Oct	Air India
12 Sep - 28 Sep	Air India
14 Sep - 24 Sep	Air India
24 Sep - 30 Sep	Air India
24 Sep - 24 Oct	Air India
02 Sep - 14 Sep	Air India
02 Sep - 10 Sep	Air India
28 Sep - 13 Oct	Air India
09 Sep - 16 Sep	Asiana Airlines
29 Sep - 15 Oct	Singapore Airlines
17 Sep - 08 Oct	Singapore Airlines
26 Sep - 10 Oct	United

Also check the deals for one-way flights from San Francisco 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 San Francisco to Bangkok in September from 517€

Return flights