Cheapest return flights from Seattle to Lisbon in December from $533

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

Return flights

06 Dec - 21 Dec United
16 Dec - 25 Dec Alaska Airlines
22 Dec - 17 Jan Scandinavian Airlines
23 Dec - 30 Dec American Airlines
21 Dec - 10 Jan KLM
20 Dec - 10 Jan Scandinavian Airlines
20 Dec - 31 Dec Sun Country Airlines

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

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 Lisbon

Cheap car rent in Lisbon

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