Cheapest return flights from Seattle to Helsinki in September from 448€

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

Return flights

09 Sep - 23 Sep Icelandair
23 Sep - 30 Sep Finnair
03 Sep - 10 Sep Finnair
16 Sep - 23 Sep Finnair
17 Sep - 24 Sep Finnair
24 Sep - 01 Oct Finnair
25 Sep - 02 Oct Finnair
26 Sep - 03 Oct Finnair
30 Sep - 07 Oct Finnair
22 Sep - 29 Sep Finnair
20 Sep - 27 Sep Finnair
09 Sep - 16 Sep Finnair
10 Sep - 17 Sep Finnair
21 Sep - 28 Sep Finnair
27 Sep - 04 Oct Finnair
28 Sep - 05 Oct Alaska Airlines
29 Sep - 06 Oct Finnair

Also check the deals for one-way flights from Seattle to Helsinki in September.

Skyscanner

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 Helsinki

Cheap car rent in Helsinki

Feel free to contact us with any feedback or request another flight research.