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

Return flights

30 Sep - 09 Oct	IndiGo
24 Sep - 05 Oct	SriLankan Airlines
18 Sep - 21 Sep	Thai Lion Air
24 Sep - 30 Sep	Thai AirAsia
20 Sep - 27 Sep	Air India
25 Sep - 30 Sep	Thai Lion Air
24 Sep - 25 Sep	Thai AirAsia
23 Sep - 05 Oct	Thai AirAsia
30 Sep - 07 Oct	Thai AirAsia
26 Sep - 05 Oct	Thai AirAsia
17 Sep - 21 Sep	Thai AirAsia
26 Sep - 01 Oct	Thai AirAsia
21 Sep - 22 Sep	Thai AirAsia
27 Sep - 06 Oct	Thai AirAsia
26 Sep - 02 Oct	Singapore Airlines	direct
26 Sep - 03 Oct	Singapore Airlines	direct
30 Sep - 07 Oct	Singapore Airlines	direct
18 Sep - 21 Sep	Singapore Airlines	direct

Also check the deals for one-way flights from Kathmandu to Singapore 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 Singapore in September from 342€

Return flights