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

Return flights

07 Sep - 17 Sep	Icelandair
06 Sep - 17 Sep	Icelandair
07 Sep - 16 Sep	Scandinavian Airlines
07 Sep - 18 Sep	Scandinavian Airlines
07 Sep - 10 Sep	Scandinavian Airlines
03 Sep - 17 Sep	Air France
03 Sep - 18 Sep	Air France
04 Sep - 17 Sep	Air France
13 Sep - 17 Sep	Scandinavian Airlines
06 Sep - 18 Sep	Scandinavian Airlines
30 Sep - 07 Oct	Lufthansa
25 Sep - 02 Oct	Lufthansa
29 Sep - 06 Oct	Lufthansa
18 Sep - 11 Oct	Brussels Airlines
24 Sep - 01 Oct	Lufthansa
28 Sep - 05 Oct	Lufthansa
26 Sep - 03 Oct	Lufthansa

Also check the deals for one-way flights from Washington to Helsinki 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 Helsinki in September from $420

Return flights