AirHint found the following cheapest return flights from Kathmandu (KTM) to Colombo (CMB) in August 2025 (see full year).

Return flights

11 Aug - 14 Aug	Air India
15 Aug - 30 Aug	Air India
17 Aug - 01 Sep	Air India
01 Aug - 08 Aug	Air India
07 Aug - 11 Aug	Air India
07 Aug - 14 Aug	Air India
31 Aug - 21 Sep	Air India
07 Aug - 11 Aug	SriLankan Airlines	direct
07 Aug - 14 Aug	SriLankan Airlines	direct
11 Aug - 14 Aug	SriLankan Airlines	direct
31 Aug - 21 Sep	SriLankan Airlines	direct
17 Aug - 01 Sep	SriLankan Airlines	direct

Also check the deals for one-way flights from Kathmandu to Colombo in August.

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 Colombo in August from $408

Return flights