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

Return flights

18 Sep - 05 Oct	Cathay Pacific
26 Sep - 12 Oct	Cathay Pacific
22 Sep - 29 Sep	Cathay Pacific
24 Sep - 27 Sep	Cathay Pacific
22 Sep - 28 Sep	Cathay Pacific
23 Sep - 29 Sep	Cathay Pacific
19 Sep - 22 Sep	Cathay Pacific
25 Sep - 02 Oct	Cathay Pacific
24 Sep - 01 Oct	Cathay Pacific
23 Sep - 27 Oct	China Airlines
29 Sep - 09 Oct	China Airlines
21 Sep - 10 Oct	Cathay Pacific
26 Sep - 12 Oct	United	direct
24 Sep - 26 Sep	United	direct
24 Sep - 29 Sep	United	direct
24 Sep - 16 Oct	United	direct
26 Sep - 03 Oct	United	direct
22 Sep - 29 Sep	United	direct
22 Sep - 28 Sep	United	direct
23 Sep - 29 Sep	United	direct

Also check the deals for one-way flights from Singapore to San Francisco 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 Singapore to San Francisco in September from $650

Return flights