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

Return flights

01 Sep - 08 Sep	IndiGo
04 Sep - 12 Sep	Thai AirAsia
08 Sep - 15 Sep	IndiGo
04 Sep - 10 Sep	Thai AirAsia
09 Sep - 16 Sep	Air India
16 Sep - 21 Sep	IndiGo
10 Sep - 20 Sep	Thai AirAsia
26 Sep - 30 Sep	IndiGo
25 Sep - 28 Sep	IndiGo
26 Sep - 03 Oct	IndiGo
26 Sep - 09 Oct	Air India
04 Sep - 10 Sep	Singapore Airlines	direct
26 Sep - 09 Oct	Singapore Airlines	direct
26 Sep - 03 Oct	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 294€

Return flights