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

Return flights

04 Sep - 14 Sep	Air Arabia
02 Sep - 09 Sep	Air Arabia
10 Sep - 15 Sep	Air Arabia
10 Sep - 17 Sep	Air Arabia
03 Sep - 08 Sep	Air Arabia
09 Sep - 13 Sep	Air Arabia
10 Sep - 14 Sep	Air Arabia
02 Sep - 11 Sep	Air Arabia
03 Sep - 12 Sep	Air Arabia
06 Sep - 14 Sep	Air Arabia
28 Sep - 10 Oct	Air Arabia
27 Sep - 10 Oct	Pegasus Airlines
26 Sep - 14 Oct	Air Arabia
27 Sep - 13 Oct	Air Arabia
25 Sep - 13 Oct	Air Arabia
29 Sep - 30 Oct	Air Arabia
28 Sep - 29 Oct	Air Arabia
27 Sep - 26 Oct	Air Arabia
26 Sep - 25 Oct	Pegasus Airlines
29 Sep - 30 Oct	Turkish Airlines	direct

Also check the deals for one-way flights from Istanbul to Kathmandu 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 Istanbul to Kathmandu in September from 414€

Return flights