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

Return flights

06 Dec - 13 Dec	Thai AirAsia X
04 Dec - 11 Dec	Thai AirAsia X
02 Dec - 09 Dec	Thai AirAsia X
11 Dec - 18 Dec	Thai AirAsia
15 Dec - 22 Dec	Thai AirAsia
19 Dec - 26 Dec	Thai AirAsia
07 Dec - 14 Dec	Thai AirAsia
09 Dec - 16 Dec	Thai AirAsia
13 Dec - 20 Dec	Thai AirAsia X
14 Dec - 21 Dec	Thai AirAsia X
29 Dec - 05 Jan	Thai AirAsia X
31 Dec - 07 Jan	Nok Air
26 Dec - 02 Jan	Thai AirAsia X
30 Dec - 06 Jan	Thai Lion Air
28 Dec - 04 Jan	Thai Lion Air
25 Dec - 01 Jan	Thai AirAsia
27 Dec - 03 Jan	Nok Air

Also check the deals for one-way flights from Bangkok 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 Bangkok to Ulaanbaatar in December from $453

Return flights