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

Return flights

03 Sep - 20 Sep	Air India
01 Sep - 21 Sep	Air India
01 Sep - 15 Sep	Air India
01 Sep - 20 Sep	Air India
09 Sep - 29 Sep	Air India
07 Sep - 21 Sep	Air India
09 Sep - 22 Sep	Air India
04 Sep - 22 Sep	Air India
03 Sep - 17 Sep	Air India
04 Sep - 18 Sep	Air India
01 Sep - 06 Oct	Air India
10 Sep - 08 Oct	Air India
03 Sep - 05 Oct	Air India
02 Sep - 06 Oct	Air India
04 Sep - 04 Oct	Air India
03 Sep - 14 Oct	Air India
18 Sep - 26 Oct	Scoot Tigerair
07 Sep - 26 Oct	Air India
03 Sep - 15 Oct	Air India
12 Sep - 13 Oct	Air India

Also check the deals for one-way flights from Sydney 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.

Book a cheap hotel in Kathmandu

Cheap car rent in Kathmandu

Cheapest return flights from Sydney to Kathmandu in September from $616

Return flights