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

Return flights

04 Sep - 10 Sep	Alaska Airlines
25 Sep - 12 Oct	Alaska Airlines
26 Sep - 05 Oct	Fiji Airways
26 Sep - 15 Oct	Fiji Airways
26 Sep - 12 Oct	Fiji Airways
13 Sep - 19 Sep	Hawaiian Airlines
07 Sep - 24 Sep	Fiji Airways
14 Sep - 01 Oct	Fiji Airways
14 Sep - 26 Oct	Fiji Airways
25 Sep - 11 Oct	Alaska Airlines
09 Sep - 16 Sep	Hawaiian Airlines
01 Sep - 01 Oct	Air New Zealand
06 Sep - 20 Sep	Alaska Airlines
23 Sep - 30 Sep	Hawaiian Airlines
16 Sep - 01 Oct	Hawaiian Airlines
16 Sep - 22 Sep	Hawaiian Airlines
23 Sep - 28 Sep	Air Canada
15 Sep - 25 Sep	Air Canada
03 Sep - 20 Sep	Air Canada
14 Sep - 26 Oct	Qantas	direct

Also check the deals for one-way flights from San Francisco to Sydney 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 Sydney in September from $657

Return flights