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

Return flights

29 Sep - 08 Oct	Singapore Airlines
11 Sep - 26 Sep	Air India
15 Sep - 22 Sep	Air India
09 Sep - 28 Sep	Air India
09 Sep - 14 Sep	Air India
13 Sep - 20 Sep	Air India
06 Sep - 17 Sep	Air India
07 Sep - 17 Sep	Air India
03 Sep - 10 Sep	Air India
12 Sep - 21 Sep	Air India
03 Sep - 14 Sep	Air India
26 Sep - 06 Oct	Air India
27 Sep - 11 Oct	Air India
08 Sep - 06 Oct	Air India
23 Sep - 23 Oct	Air India
16 Sep - 29 Oct	Delta

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 $561

Return flights