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

Return flights

12 Sep - 21 Sep	Air India
14 Sep - 17 Sep	Air India
11 Sep - 17 Sep	Air India
12 Sep - 19 Sep	Air India
14 Sep - 24 Sep	Air India
13 Sep - 20 Sep	Air India
15 Sep - 20 Sep	Air India
29 Sep - 04 Oct	Air India
09 Sep - 09 Sep	Air India
27 Sep - 03 Oct	Air India
30 Sep - 05 Oct	Air India
28 Sep - 02 Oct	Air India
27 Sep - 04 Oct	Air India
25 Sep - 30 Sep	Air India
27 Sep - 11 Oct	Air India
27 Sep - 05 Oct	Air India

Also check the deals for one-way flights from Kolkata 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 Kolkata to Kathmandu in September from 232€

Return flights