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

Return flights

17 Sep - 24 Sep	Thai Lion Air
18 Sep - 25 Sep	Thai AirAsia
20 Sep - 27 Sep	Thai Lion Air
23 Sep - 30 Sep	Thai AirAsia
22 Sep - 29 Sep	Thai AirAsia
19 Sep - 26 Sep	Thai Lion Air
24 Sep - 01 Oct	Thai AirAsia
27 Sep - 04 Oct	Thai AirAsia X
21 Sep - 28 Sep	Thai AirAsia X
28 Sep - 05 Oct	Thai AirAsia X
26 Sep - 03 Oct	Thai AirAsia X
30 Sep - 07 Oct	Thai Lion Air
25 Sep - 02 Oct	Thai AirAsia
29 Sep - 06 Oct	Thai AirAsia

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

Book a cheap hotel in Ulaanbaatar

Cheap car rent in Ulaanbaatar

Cheapest return flights from Bangkok to Ulaanbaatar in September from $400

Return flights