AirHint found the following cheapest return flights from Seoul (ICN) to Kathmandu (KTM) in December 2025 (see full year).

Return flights

03 Dec - 14 Dec	SriLankan Airlines
03 Dec - 14 Jan	SriLankan Airlines
31 Dec - 04 Jan	SriLankan Airlines
29 Dec - 03 Jan	Air China
18 Dec - 31 Jan	Air China
01 Dec - 10 Dec	Air China
19 Dec - 27 Dec	Air China
13 Dec - 20 Dec	Air India
20 Dec - 27 Dec	Air India
16 Dec - 27 Dec	Air India
25 Dec - 03 Jan	Air India
27 Dec - 03 Jan	Air India
27 Dec - 10 Jan	Air India
30 Dec - 03 Jan	Air India
16 Dec - 29 Dec	Air India
01 Dec - 15 Dec	Thai Airways
06 Dec - 12 Dec	Thai Airways
30 Dec - 30 Jan	Air India
29 Dec - 05 Jan	Thai Airways
16 Dec - 30 Dec	Thai Airways

Also check the deals for one-way flights from Seoul to Kathmandu 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 Seoul to Kathmandu in December from 290€

Return flights