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

Return flights

02 Dec - 09 Dec	Air China
15 Dec - 22 Dec	Air China
15 Dec - 14 Jan	Air China
27 Dec - 03 Jan	Air China
24 Dec - 23 Jan	Air China
15 Dec - 01 Jan	Jetstar
22 Dec - 29 Dec	Qantas
22 Dec - 19 Jan	Air China
23 Dec - 19 Jan	Air China
27 Dec - 02 Jan	Cathay Pacific
21 Dec - 19 Jan	Qantas
22 Dec - 03 Jan	Qantas

Also check the deals for one-way flights from Sydney to Ulaanbaatar 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 Sydney to Ulaanbaatar in December from 1026€

Return flights