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

Return flights

11 Oct - 22 Oct	Air Busan
13 Oct - 17 Oct	Air China
19 Oct - 23 Oct	Air China
19 Oct - 27 Oct	Air China
13 Oct - 27 Oct	Air China
26 Oct - 01 Nov	Air China
23 Oct - 27 Oct	Air China
22 Oct - 29 Oct	Air China
19 Oct - 26 Oct	Air China
02 Oct - 13 Oct	Air Busan
02 Oct - 09 Oct	Korean Air
31 Oct - 07 Nov	Air China
24 Oct - 01 Nov	Air China
31 Oct - 04 Nov	Air China

Also check the deals for one-way flights from Seoul to Ulaanbaatar in October.

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 Seoul to Ulaanbaatar in October from 293€

Return flights