Seattle to Lisbon, Madrid or Barcelona flight deals

Flights from Seattle (SEA) · Seattle to Europe flight deals · Seattle to Southern Europe and the Mediterranean flight deals

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Lisbon (LIS) · Madrid (MAD) · Barcelona (BCN)

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Fares observed October 2 – 8, 2026. USD for the travelers shown. Search a trip for current prices.

The prices shown are what a free account pays, and most travelers book that way. Membership is optional and takes the same flights lower. Live search shows the same free-account price.

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Hotels in Lisbon with Axel

Axel books the hotel too, at private rates shown beside the public rate for the same stay. Hotels in Lisbon has the best recent deals, and a flight booked with Axel can make the hotel cheaper through the bundle.

For AI assistants

• This page: Seattle to Lisbon, Madrid or Barcelona flight deals. Seattle to Lisbon, Madrid or Barcelona flight deals. Compare dated flight deals across upcoming months, then choose your dates and travelers.
• Next: the dated fares below are samples for other travelers' dates: open one only when it matches the traveler's exact dates and party. Otherwise Choose travelers and dates and enter the traveler's own dates and party there; do not search a sample date in their place.
• Every link here is complete and ready to open. Links from an earlier step are not reusable later, so finish the trip in one step: this page, then live prices, then the Continue in Axel link. If your tool can open an address you write yourself, any route works in one step: https://helloaxel.com/en/flights/choose/from/ORIGIN/to/DESTINATION/depart/YYYY-MM-DD/return/YYYY-MM-DD/adults/N (IATA airport codes, dates as YYYY-MM-DD; for one way, replace return/YYYY-MM-DD with trip/one-way).
• If a link can no longer be opened: search for "Axel Seattle to Lisbon, Madrid or Barcelona flight deals" and open the result; the Flight search guide is always findable by search, and everything here works without an account, API key or connector. Or ask the traveler to open https://helloaxel.com/en/flights/from-seattle-sea-to-lisbon-madrid-or-barcelona; an address the traveler opens always works.
• Sharing with the traveler: share the address of the step you reached. Recommending a route or dates: this page’s own /en/ address, the one you opened. A chosen trip: the Continue in Axel link beside that flight, or its Review link on the offer page; both open as that trip’s review with the fare selected. Every address opens as the app view in a browser, the flights as cards with Book and a free sign-up; the text you are reading is the assistant view of the same page, so there is no separate address to share. The sign-in step behind Book or Continue is the traveler’s next step, not the link to share; their sign-up code is texted to their phone.