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

Return flights

06 Dec - 27 Dec	Qantas
11 Dec - 18 Dec	United
23 Dec - 31 Dec	Turkish Airlines
23 Dec - 14 Jan	Turkish Airlines
16 Dec - 22 Dec	United
26 Dec - 21 Jan	American Airlines
19 Dec - 13 Jan	jetBlue
23 Dec - 03 Jan	Qantas
18 Dec - 31 Dec	jetBlue
19 Dec - 12 Jan	jetBlue
20 Dec - 04 Jan	American Airlines
19 Dec - 10 Jan	Azores Airlines
20 Dec - 16 Jan	Hawaiian Airlines
18 Dec - 25 Dec	Hawaiian Airlines
30 Dec - 04 Jan	Turkish Airlines
19 Dec - 11 Jan	jetBlue
19 Dec - 31 Dec	Qantas

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

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 Boston to Sydney in December from $1377

Return flights