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

Return flights

28 Dec - 05 Jan	Air China
26 Dec - 02 Jan	Air China
28 Dec - 04 Jan	Air China
29 Dec - 05 Jan	Air China
25 Dec - 01 Jan	Air China
27 Dec - 03 Jan	Air China
30 Dec - 06 Jan	Air China
22 Dec - 29 Dec	Air China
23 Dec - 25 Dec	Air China
24 Dec - 24 Jan	Air China
21 Dec - 28 Dec	Air China
15 Dec - 17 Dec	Air China
15 Dec - 22 Dec	Air China
23 Dec - 30 Dec	Air China
20 Dec - 27 Dec	Air China
17 Dec - 24 Dec	Air China
13 Dec - 19 Dec	Air China
24 Dec - 31 Dec	Asiana Airlines
22 Dec - 22 Jan	Air China
27 Dec - 31 Jan	Air China

Also check the deals for one-way flights from Seoul 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.

Book a cheap hotel in Ulaanbaatar

Cheap car rent in Ulaanbaatar

Cheapest return flights from Seoul to Ulaanbaatar in December from $373

Return flights