OPO - SEA

$467 Find Cheap Flights from Porto to Seattle

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Porto to Seattle departing on 11/2. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Seattle

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Porto to Seattle, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Porto to Seattle, as well as popular online travel agencies
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Flight Deals

Cheap Flights from Porto to Seattle (OPO-SEA)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Porto to Seattle that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Porto to Seattle

Thu, Oct 2 - Tue, Oct 7
KLM Logo
8:20 pm - 11:50 amOPO-SEA
23h 30m1 stop
KLM Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
$775KLM
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Thu, Oct 2 - Tue, Oct 7
Delta Logo
6:30 am - 4:05 pmOPO-SEA
17h 35m1 stop
Delta Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
$776Delta
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Thu, Oct 2 - Tue, Oct 7
Delta Logo
6:30 am - 10:06 pmOPO-SEA
23h 36m2 stops
Delta Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
$781Delta
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Thu, Oct 2 - Tue, Oct 7
Delta Logo
6:30 am - 10:06 pmOPO-SEA
23h 36m2 stops
Delta Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
$782Delta
Find Deal
Thu, Oct 2 - Tue, Oct 7
Multiple Airlines Logo
10:00 pm - 8:40 pmOPO-SEA
30h 40m3 stops
Multiple Airlines Logo
3:45 pm - 8:00 amSEA-OPO
32h 15m3 stops
$811Multiple Airlines
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Thu, Oct 2 - Tue, Oct 7
Multiple Airlines Logo
10:00 pm - 8:40 pmOPO-SEA
30h 40m3 stops
Multiple Airlines Logo
7:00 pm - 6:50 pmSEA-OPO
15h 50m2 stops
$812Multiple Airlines
Find Deal
Mon, Oct 13 - Mon, Oct 20
Lufthansa Logo
6:00 am - 11:55 amOPO-SEA
13h 55m1 stop
Lufthansa Logo
7:00 am - 10:20 amSEA-OPO
19h 20m2 stops
$832Lufthansa
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Mon, Oct 13 - Mon, Oct 20
Lufthansa Logo
6:00 am - 11:55 amOPO-SEA
13h 55m1 stop
Lufthansa Logo
2:20 pm - 3:45 pmSEA-OPO
17h 25m1 stop
$835Lufthansa
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Mon, Oct 13 - Mon, Oct 20
United Airlines Logo
12:10 pm - 6:49 pmOPO-SEA
38h 39m2 stops
United Airlines Logo
8:00 am - 9:45 amSEA-OPO
17h 45m2 stops
$895United Airlines
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Wed, Nov 12 - Sun, Nov 23
American Airlines Logo
8:20 am - 11:18 pmOPO-SEA
22h 58m2 stops
American Airlines Logo
5:48 am - 7:40 amSEA-OPO
17h 52m2 stops
$3,824American Airlines
Find Deal

Everything you should know

Top airlines
KLM
Cheapest • from $775 (round-trip)
KLM
Best reviews • 7.8 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Cheapest round-trip
$775
KLM
Thu 10/2Tue 10/7
OPO - SEA • 1 stop
Cheapest one-way
$467
Typical prices: $736-877
Multiple Airlines
Sun 11/2
OPO - SEA • 3 stops
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KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Seattle!
Booking Insights

KAYAK's insights & trends for Porto to Seattle flights

Get data-powered insights and trends into flights from Porto to Seattle to help you find the cheapest flights, the best time to fly and much more.

How much is a round-trip flight from Porto to Seattle?

What’s the cheapest day of the week to fly from Porto to Seattle?

The average price of all round-trip flights from Porto to Seattle clicked on KAYAK for each day over the last 12 months.

For Porto to Seattle, Monday is the cheapest day to fly on average and Saturday is the most expensive. Flying from Seattle back to Porto, the best deals are generally found on Tuesday, with Thursday being the most expensive.

Find deals

Good to know

Low seasonOctober
Cheapest flight$467
Best time to beat the crowds with an average 63% drop in price.
Most popular time to fly with an average 20% increase in price.
Flight from Porto to Seattle

When to book flights from Porto to Seattle

Are your dates flexible? Find out the best times to travel from Porto to Seattle based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Porto to Seattle

  • What is the cheapest flight from Porto to Seattle?

    In the last 3 days, the lowest price for a flight from Porto to Seattle was $467 for a one-way ticket and $775 for a round-trip.

  • Do I need a passport to fly between Porto and Seattle?

    A passport is required to fly from Porto to Seattle.

  • Which aircraft models fly most regularly from Porto to Seattle?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from Porto to Seattle?

    Star Alliance, oneworld, and SkyTeam are the airline alliances operating flights between Porto and Seattle, with oneworld being the most commonly used for this route.

  • How does KAYAK find such low prices on flights from Porto to Seattle?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Porto to Seattle.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Porto to Seattle?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Seattle from Porto is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Porto to Seattle?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Seattle with an airline and back to Porto with another airline. Booking your flights between Porto and SEA can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Porto to Seattle?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Seattle from Porto up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top airline flying from Porto to Seattle

 
See real verified KAYAK customer reviews for airlines flying from Porto to Seattle. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Porto to Seattle? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.8
KLMOverall score based on 1386 reviews
7.2Entertainment
8.4Crew
7.7Comfort
7.3Food
7.8Boarding
Airline reviews

The immigration hall in Amsterdam was understaffed, so passport checking was slower than it should be for a major airport. They need to get the automatic readers up and running for non EU passport holders. Waiting in line after a long flight feels a bit abusive.

10.0 ExcellentCameron, Sep 2025YYJ - YYC
Read more KLM reviews

The immigration hall in Amsterdam was understaffed, so passport checking was slower than it should be for a major airport. They need to get the automatic readers up and running for non EU passport holders. Waiting in line after a long flight feels a bit abusive.

Over 1 Hr delay. No APU so no AC on ground. Plane was hot during boarding and then they closed the doors over 20 minutes before engine start so interior of plane was steamy hot and stuffy. Could have been helped by opening doors until ready to depart.

Ad experience - been flying many years with them but they are losing out to other carriers with their service and bagage / seating policy. My 2 12-yo kids were not placed with the parent. Absurdity.

Short flight so it was okay. Nice crew, all very pleasant and professional. We were near the back in row 27 so just as we got our drinks, we started our descent so had to drink very quickly!

KLM remains a quality flag carrier airline which maintains its standards whilst all their competitors are lowering theirs.

Our first flight was delayed so we missed our connecting flight. However it was easy to book a later flight on their app.

My flight was delayed by 6 hours then I missed BOTH of my connecting flights, I then had to stay in the AIRPORT at JFK because soooooo many people also suffered from missing flights and there was no hotels available. I would like to be compensated for this experience! I had to stay in the airport for over 16 hours!

I appreciate that KLM was proactive in informing me of the 2 hour delay which enabled me to replan my travel. It was a bit stressful not knowing whether my connection from Montreal to Ottawa was happening. But the ground and air crew did a good job at comforting and assuring me.

Cabin crew were excellent, very proffesional, polite and friendly, in flight snack was underwhelming, a packet of cheese biscuits, im sure KLM could run to a sandwich!

Legroom not all it could be, especially when the seat in front is reclined. Otherwise it was good, food and beverage were nice.

Everything you need to know for your flight from Porto to Seattle

Information on your arrival and departure airports

Porto (OPO)
Seattle (SEA)

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