Cheapest return flights from Washington to Sydney in September from $1023

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

Return flights

24 Sep - 13 Oct Frontier Airlines
18 Sep - 22 Sep Frontier Airlines
03 Sep - 10 Sep Etihad Airways
21 Sep - 11 Oct Sun Country Airlines
06 Sep - 13 Sep Frontier Airlines
08 Sep - 23 Sep Turkish Airlines
03 Sep - 13 Sep Turkish Airlines
02 Sep - 08 Sep Cathay Pacific
14 Sep - 19 Sep Turkish Airlines
09 Sep - 18 Sep Emirates

Also check the deals for one-way flights from Washington to Sydney in September.

Skyscanner

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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