AirHint found the following cheapest one-way flights from Washington (IAD) to Sydney (SYD) in September 2025 (see full year).
One-Way flights
| 17 Sep | Frontier Airlines | ||
| 10 Sep | Frontier Airlines | ||
| 21 Sep | Hawaiian Airlines | ||
| 19 Sep | Hawaiian Airlines | ||
| 30 Sep | Delta | ||
| 14 Sep | United |
Also check the deals for return flights from Washington 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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