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

Return flights

20 Sep - 25 Sep	Air Canada
20 Sep - 28 Sep	Air Canada
21 Sep - 28 Sep	Air Canada
11 Sep - 28 Sep	Air Canada
04 Sep - 11 Sep	Air Canada
09 Sep - 16 Sep	Air Canada
05 Sep - 11 Sep	Singapore Airlines	direct
03 Sep - 11 Sep	Air Canada
01 Sep - 09 Sep	Zipair
02 Sep - 09 Sep	Zipair
24 Sep - 16 Oct	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 $707

Return flights