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

Return flights

29 Sep - 28 Oct	China Southern
29 Sep - 24 Oct	China Southern
26 Sep - 24 Oct	China Southern
28 Sep - 27 Oct	China Southern
29 Sep - 20 Oct	Air China
20 Sep - 27 Sep	Thai AirAsia
23 Sep - 28 Sep	Thai Lion Air
23 Sep - 27 Sep	Nepal Airlines
26 Sep - 13 Oct	Thai Airways
23 Sep - 14 Oct	Thai Airways
22 Sep - 27 Sep	Air India
22 Sep - 28 Sep	Nepal Airlines
26 Sep - 10 Oct	Thai Airways
19 Sep - 27 Oct	Thai Airways
22 Sep - 10 Oct	China Southern
19 Sep - 26 Sep	Thai AirAsia
17 Sep - 21 Sep	Thai Airways
22 Sep - 26 Sep	Air India
27 Sep - 29 Sep	Thai Airways
22 Sep - 29 Sep	Singapore Airlines

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

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Cheapest return flights from Kathmandu to Seoul in September from 469€

Return flights