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OPO - SEA

$428 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 6/8. 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.
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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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Cheap Flights from Porto to Seattle

 
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.

Recent round-trip flight deals from Porto to Seattle

KAYAK's recommended round-trip deals from the most popular airlines that fly from Porto to Seattle.
Discover the best prices for you by selecting your travel dates on KAYAK.
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KLM Logo
11:25 am - 11:40 amOPO-SEA
32h 15m1 stop
KLM Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
$779KLM
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Thu, May 22 - Thu, May 29
Logo
6:30 am - 7:55 pmOPO-SEA
21h 25m2 stops
Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
$789
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Thu, May 22 - Thu, May 29
Delta Logo
6:30 am - 7:55 pmOPO-SEA
21h 25m2 stops
Delta Logo
10:25 am - 3:30 pmSEA-OPO
21h 05m2 stops
$800Delta
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Thu, May 22 - Thu, May 29
Logo
12:25 pm - 12:25 pmOPO-SEA
32h 00m2 stops
Logo
2:15 pm - 8:00 amSEA-OPO
33h 45m3 stops
$810
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Thu, May 22 - Thu, May 29
SWISS Logo
7:20 pm - 9:11 pmOPO-SEA
33h 51m2 stops
SWISS Logo
2:50 pm - 7:55 amSEA-OPO
33h 05m2 stops
$824SWISS
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Thu, May 22 - Thu, May 29
United Airlines Logo
6:00 am - 12:25 pmOPO-SEA
14h 25m1 stop
United Airlines Logo
2:05 pm - 6:55 amSEA-OPO
32h 50m1 stop
$843United Airlines
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Thu, May 22 - Thu, May 29
British Airways Logo
7:30 pm - 11:35 amOPO-SEA
24h 05m1 stop
British Airways Logo
1:30 pm - 8:20 pmSEA-OPO
22h 50m1 stop
$862British Airways
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Thu, May 22 - Thu, May 29
United Airlines Logo
6:00 am - 12:25 pmOPO-SEA
14h 25m1 stop
United Airlines Logo
11:50 pm - 6:55 amSEA-OPO
23h 05m2 stops
$864United Airlines
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Thu, May 22 - Thu, May 29
Logo
12:00 pm - 12:25 pmOPO-SEA
32h 25m3 stops
Logo
2:15 pm - 9:20 pmSEA-OPO
23h 05m3 stops
$882
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Thu, May 22 - Thu, May 29
Delta Logo
5:00 am - 6:46 pmOPO-SEA
21h 46m2 stops
Delta Logo
9:25 am - 10:40 amSEA-OPO
17h 15m2 stops
$937Delta
Find Deal
Sun, Jun 1 - Mon, Jun 9

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.

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.

What is the cheapest month to fly from Porto to Seattle?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Porto to Seattle, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.
The cheapest month for flights from Porto to Seattle is October, where tickets cost $332 (return) on average. On the other hand, the most expensive months are June and July, where the average cost of round-trip tickets is $1,467 and $1,056 respectively.
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Good to know

Low season

January

High season

July

Cheapest flight

$428
Best time to beat the crowds with an average 0% drop in price.
Most popular time to fly with an average 17% 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 $428 for a one-way ticket and $779 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?

    SkyTeam, Star Alliance, and oneworld are the airline alliances operating flights between Porto and Seattle, with Star Alliance 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.

See more FAQs

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 1321 reviews
7.8Boarding
7.7Comfort
8.4Crew
7.1Entertainment
7.3Food
Airline reviews

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

8.0 ExcellentAnonymous, Apr 2025AMS - INL
Read more KLM reviews

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

This portion of the flight was through Indigo. A local carrier. So all economy seating. No real service some refreshments for purchase standard economy stuff.

This fight left ahead of time which meant it arrived early which was great. Staff were very professional, but as with all these Short hop Flights the food was a disappointing snack There was no entertainment on this flight, but I did not expect any

I flew premium economy and this was a good option. Although the seats didn’t recline much, I was able to get some sleep with my head propped against the window. The food was good and the entertainment was wonderful The staff were very attentive and professional

They only had vegetarian food left on the flight which I wasn’t happy about. I didn’t get any food to eat at all.

Great boarding, great short flight but no entertainment whatsoever. It was supposed to have wifi but that did not work.

Transfer at CDG to connecting KLM flight to Amsterdam was a NIGHTMARE. LONG WALKWAYS, NO MOVING WALKWAYS, POOR signage, Have to take a train & No staff visible to help navigate the maze. AVOID TRANSFER AT CDG AT ALL COST.

Good food. Excellent crew service. Clean aircraft. Narrow seats and isle.

There was fog in Amsterdam so many flights were delayed because of the weather. Air France knew that the flight would be delayed by two hours but still boarded the plane on time. Instead of letting the passengers wait at the gate we were crammed into the plane. It was uncomfortable. No refreshments were given. I couldn’t charge my devices onboard.

I tried to upgrade to premium economy anis seat online during the checkin process. The payment didn’t work due to a technical glitch on KLM’s website. I wasn’t able to change my seat unless I called Amsterdam. Since I was in Canada and there’s a time difference this wasn’t practical. So when I arrived early to Ottawa airport my seat wasn’t available and I could only get a middle seat in premium economy which isn’t great. These middle seats are priced at the same rate as an aisle seat which makes no sense.

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

Information on your arrival and departure airports

Seattle (SEA)
Porto (OPO)

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