Cheapest return flights from Seattle to Sydney in December from $1146

AirHint found the following cheapest return flights from Seattle (SEA) to Sydney (SYD) in December 2025 (see full year).

Return flights

27 Dec - 10 Jan Fiji Airways
11 Dec - 02 Jan Alaska Airlines
15 Dec - 05 Jan Alaska Airlines
24 Dec - 17 Jan Air Canada
25 Dec - 17 Jan Air Canada
23 Dec - 15 Jan ANA
09 Dec - 06 Jan United
24 Dec - 31 Dec United
23 Dec - 17 Jan EVA Air
27 Dec - 11 Jan United
22 Dec - 28 Dec Air Canada

Also check the deals for one-way flights from Seattle to Sydney in December.

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.

Book a cheap hotel in Sydney

Cheap car rent in Sydney

Feel free to contact us with any feedback or request another flight research.