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

Return flights

03 Dec - 04 Dec	Batik Air Malaysia
03 Dec - 15 Dec	Air China
04 Dec - 20 Dec	Air China
05 Dec - 20 Dec	Air China
03 Dec - 20 Dec	Air China
03 Dec - 06 Dec	Cathay Pacific
23 Dec - 25 Jan	Air China
05 Dec - 08 Dec	Cathay Pacific
23 Dec - 20 Jan	Air China
05 Dec - 21 Dec	Cathay Pacific
10 Dec - 13 Dec	Cathay Pacific
26 Dec - 02 Jan	Air China
27 Dec - 30 Dec	Asiana Airlines

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 $1050

Return flights