Cheapest return flights from Seattle to Lisbon in September from $660

Best time to book flights for Seattle (SEA) to Lisbon (LIS) flights at AirHint

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

Return flights

28 Sep - 08 Oct Scandinavian Airlines
10 Sep - 17 Sep Scandinavian Airlines
02 Sep - 09 Sep Icelandair
05 Sep - 01 Oct Scandinavian Airlines
10 Sep - 25 Sep Scandinavian Airlines
12 Sep - 26 Sep Scandinavian Airlines
06 Sep - 13 Sep Icelandair
17 Sep - 25 Sep Scandinavian Airlines
07 Sep - 14 Sep Icelandair
18 Sep - 26 Sep Turkish Airlines
08 Sep - 15 Sep Icelandair
15 Sep - 22 Sep Turkish Airlines

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

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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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