AirHint found the following cheapest return flights from Washington (IAD) to Colombo (CMB) in September 2025 (see full year).

Return flights

03 Sep - 10 Sep	Saudia
13 Sep - 28 Sep	Saudia
28 Sep - 13 Oct	Etihad Airways
15 Sep - 30 Sep	Etihad Airways
10 Sep - 15 Oct	Etihad Airways
30 Sep - 19 Oct	Etihad Airways
13 Sep - 20 Sep	Etihad Airways
05 Sep - 13 Sep	Etihad Airways
02 Sep - 09 Sep	Qatar Airways

Also check the deals for one-way flights from Washington to Colombo 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 Washington to Colombo in September from $816

Return flights