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

Return flights

05 Sep - 19 Sep	VietJet Air
09 Sep - 22 Sep	T'way Air
23 Sep - 11 Oct	Air China
03 Sep - 08 Sep	Cathay Pacific
03 Sep - 09 Sep	Cathay Pacific
03 Sep - 10 Sep	Cathay Pacific
02 Sep - 07 Sep	Qantas
07 Sep - 14 Sep	Qantas
01 Sep - 14 Sep	Cathay Pacific
01 Sep - 17 Sep	Qantas
16 Sep - 04 Oct	Air China
23 Sep - 04 Oct	Air China
30 Sep - 11 Oct	Air China
27 Sep - 11 Oct	Air China
10 Sep - 30 Sep	Cathay Pacific

Also check the deals for one-way flights from Sydney to Ulaanbaatar 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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Cheapest return flights from Sydney to Ulaanbaatar in September from $773

Return flights