SEA - OPO

$321 Find Cheap Flights from Seattle to Porto

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Seattle to Porto departing on 8/16. 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, 0 bags

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

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to Porto.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to Porto.
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Everything you should know

Cheapest round-trip
$621
Typical prices: $769-$651
Lufthansa
Fri 10/2Fri 10/16
SEA - OPO • 1 stop
Cheapest one-way
$321
Typical prices: $351-$928
Multiple Airlines
Sun 8/16
SEA - OPO • 3 stops
Top airlines
Cheapest • from $621 (round-trip)
Best reviews • 7.9 score
Airline reviews
Airline reviews
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Airline reviews
Airline reviews
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Nonstop flights
Not available
There are currently no direct flights between Seattle and Porto. You'll need at least 1 connection.
Insights
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Insights
Top layover airports
Cheapest • Avg $794 (round-trip)
Shortest trip • 14h 17m (one-way)
Insights
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Insights
When to book
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 62% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 44% price drop
Most popular
Good to know
Good to know
+1
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Good to know
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We hope you love your trip to Porto!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Seattle to Porto (SEA-OPO)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle to Porto 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 Seattle to Porto

Fri, Oct 2 - Fri, Oct 16
Lufthansa Logo
6:50 pm - 11:25 pm
SEA
-
OPO
20h 35m
1 stop
Lufthansa Logo
6:20 am - 4:59 pm
OPO
-
SEA
18h 39m
1 stop
$621Lufthansa
Fri, Oct 2 - Fri, Oct 16
Lufthansa Logo
6:50 pm - 11:25 pm
SEA
-
OPO
20h 35m
1 stop
Lufthansa Logo
6:00 am - 4:59 pm
OPO
-
SEA
18h 59m
2 stops
$655Lufthansa
Sun, Nov 1 - Wed, Nov 11
British Airways Logo
10:35 am - 4:40 pm
SEA
-
OPO
22h 05m
2 stops
British Airways Logo
8:40 pm - 9:18 pm
OPO
-
SEA
32h 38m
2 stops
$777British Airways
Sun, Nov 8 - Mon, Nov 23
Scandinavian Airlines Logo
7:20 am - 11:05 am
SEA
-
OPO
19h 45m
2 stops
Scandinavian Airlines Logo
11:55 am - 10:11 pm
OPO
-
SEA
42h 16m
2 stops
$778Scandinavian Airlines
Wed, Sep 16 - Tue, Sep 22
Turkish Airlines Logo
7:10 pm - 3:45 pm
SEA
-
OPO
36h 35m
1 stop
Turkish Airlines Logo
10:40 am - 5:15 pm
OPO
-
SEA
38h 35m
1 stop
$791Turkish Airlines
Wed, Oct 7 - Thu, Oct 15
Turkish Airlines Logo
7:10 pm - 9:40 am
SEA
-
OPO
30h 30m
1 stop
Turkish Airlines Logo
11:00 am - 5:15 pm
OPO
-
SEA
38h 15m
1 stop
$792Turkish Airlines
Wed, Oct 7 - Thu, Oct 15
British Airways Logo
1:30 pm - 7:05 pm
SEA
-
OPO
21h 35m
1 stop
British Airways Logo
8:20 am - 12:14 am
OPO
-
SEA
23h 54m
2 stops
$795British Airways
Sun, Oct 11 - Wed, Oct 21
American Airlines Logo
12:00 pm - 4:00 pm
SEA
-
OPO
20h 00m
2 stops
American Airlines Logo
12:25 pm - 12:15 am
OPO
-
SEA
19h 50m
2 stops
$799American Airlines
Mon, Oct 5 - Wed, Oct 14
American Airlines Logo
12:57 pm - 4:00 pm
SEA
-
OPO
19h 03m
2 stops
American Airlines Logo
12:25 pm - 12:15 am
OPO
-
SEA
19h 50m
2 stops
$800American Airlines
Wed, Oct 21 - Wed, Dec 16
Multiple Airlines Logo
5:40 am - 6:30 pm
SEA
-
OPO
28h 50m
2 stops
Multiple Airlines Logo
4:05 pm - 12:10 pm
OPO
-
SEA
28h 05m
1 stop
$802Multiple Airlines
Booking Insights

KAYAK's insights & trends for Seattle to Porto flights

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

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

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Seattle to Porto departing in October.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Seattle to Porto, 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 Seattle to Porto is January, where tickets cost $498 (return) on average. On the other hand, the most expensive months are December and August, where the average cost of round-trip tickets is $1,451 and $1,061 respectively.

How far in advance should I book a flight from Seattle to Porto?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Seattle to Porto, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Seattle to Porto, you should book around 3 weeks before departure, which saves you about 62% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 24 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$321
Best time to beat the crowds with an average 44% drop in price.
Most popular time to fly with an average 16% increase in price.
Flight from Seattle to Porto

When to book flights from Seattle to Porto

Are your dates flexible? Find out the best times to travel from Seattle to Porto 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 Seattle to Porto

  • Do I need to get a visa before this flight?

    Traveling to Portugal for a stay in the Schengen area is hassle-free if your trip is for under 90 days within a 180-day timeframe. No visa is required for this duration. Keep in mind that a new 180-day period starts after spending 90 consecutive days outside the Schengen area. This allows you to enjoy your stay in Portugal without worrying about obtaining a visa.

  • What are some reasons to consider upgrading to First Class on Delta Air Lines?

    Enjoy the comfort of wider and more spacious seats and the added convenience of ticket flexibility without change fees. With Sky Priority service, your journey will be well-crafted from the beginning to the end. Indulge in a travel experience like no other, making your trip truly unforgettable in First Class.

  • What is a good choice for a sustainable airline on this trip?

    United Airlines is deeply dedicated to operating as an environmentally sustainable and responsible airline, with this commitment deeply embedded in its strategy and core principles. By the year 2050, the airline strives to achieve a remarkable goal of completely eliminating 100% of its greenhouse gas (GHG) emissions, going beyond the conventional reliance on carbon offsets. As part of its mid-term objective, United aims to reduce its carbon intensity by an impressive 50% by the year 2035, comparing against the levels recorded in 2019.

  • If I have special dietary needs, what is a good airline choice?

    On KLM, you have the convenience of ordering a customized meal that caters to your specific dietary needs. They offer various options, including low-fat, low-salt, meals suitable for diabetic, gluten-intolerance, or lactose-intolerance diets. Additionally, there is a limited number of vegetarian meals available on each flight. To ensure you receive your preferred vegetarian or vegan meal, it is advisable to place your order at least 24 h before your scheduled departure.

  • What is the cheapest flight from Seattle to Porto?

    In the last 3 days, the lowest price for a flight from Seattle to Porto was $321 for a one-way ticket and $621 for a round-trip.

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

    Yes, you’ll need a passport to travel to Porto from Seattle.

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

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

  • Which airline alliances offer flights from Seattle to Porto?

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

  • Which is the best airline for flights from Seattle to Porto, Delta or KLM?

    The two airlines most popular with KAYAK users for flights from Seattle to Porto are Delta and KLM. With an average price for the route of $947 and an overall rating of 7.9, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $940 and an overall rating of 7.8.

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

    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 Seattle to Porto.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Porto from Seattle 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 Seattle to Porto?

    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 Porto with an airline and back to Seattle with another airline. Booking your flights between Seattle and OPO 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 Seattle to Porto?

    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 Porto from Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Seattle to Porto

  • If you would like a way to Seattle Tacoma International Airport (SEA) that does not involve driving yourself, check out the 1-Line from Sound Transit that riders can take from Pioneer Square Station to the airport in about 33 minutes.
  • Because there are no direct flights available on this trip, some layover airports you can expect to use include Amsterdam Airport Schiphol (AMS), San Francisco International Airport (SFO), and Zurich Airport (ZRH).
  • When you fly with WestJet, carry-in bags can be no bigger than 21 x 9 x 15 inches, and a personal item can be no larger than 16 x 16 x 13 inches. There is no weight limit for either bag.
  • Before checking bags on Air France flights, make sure bags don't exceed linear dimensions greater than 62.2 inches, including wheels, pockets, and handles. The weight allowance for Economy Classes is a maximum of 50 lb, while Business and La Premiere Classes allow up to 70 lb.
  • When flying with American Airlines, you are permitted to bring one golf bag containing golf clubs, golf balls, golf tees, and one pair of golf shoes. It's essential to be aware that standard checked bag fees, which vary depending on your destination, will apply to bags weighing up to 50 lb and measuring up to 126 inches in total dimensions.

Reviews of the top 5 airlines serving from Seattle to Porto

 
See real verified KAYAK customer reviews for airlines flying from Seattle to Porto. 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 Seattle to Porto? 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.
7.9
DeltaOverall score based on 8450 reviews
7.8Entertainment
8.5Crew
7.8Comfort
7.2Food
8.1Boarding
Airline reviews

Delta does a great job with entertainment and free wifi. I can still be in touch with my colleagues while in the air.

10.0 ExcellentMark, May 2026
ATL - SYR
Read more Delta reviews

Delta does a great job with entertainment and free wifi. I can still be in touch with my colleagues while in the air.

Aside from a completely packed plane, I really have no complaints.

Bus to plane was delayed for no apparent reason and our luggage was still on the belt when they shut it off. Took about 20 minutes to turn it back on to get our luggage.

It was a pleasant surprise to have complimentary Wi-Fi on the flight

Much better than Latam, the worse airline company ever. I hope I don't have the need to fly Latam ever in my life again.

Seats in Delta Main are unbelievably close to the seat in front of. Hard to get a backpack under the seat.

The flight was operated by Latam. The aircraft had a technical issue and the flight was delayed for the next day. They grounded other passengers to get their airplane assigned to my flight. Most of he ground staff don't speak English (Orlando Airport), but were very polite.The crew on the other hand could speak English and Portuguese. On board service was good.

The agent at check in and at the gate were less than thrilled to be at work. I'm not a fan of Kayak's placement on the plane. I got put in the middle seat and none of my preferences were used.

In ATL they have two sets of departure screens. Follow what is on your airline's departure board - the ATL Airport Authority departure board had completely incorrect details about the gate assignment for my flight, which would have made me miss boarding.

Flight was delayed it was hot while sitting on the plane, one engine was working on the plane until they had to do some jimmy rigging down the runway in order for the other engine to charge up. It was ridiculous

Brand new plane lots of room the snack was very flavourful and enjoyable

The flight was delayed. The aircraft was unclean. Promised seat was not given due to change in Aircraft. Not one crew on ground was in a position to give any response. Amsterdam Airport is AVIODABLE Over crowded. Over Expensive. Poor Services.

It was really nice journey i personally recommend klm flight

The crew were unprofessional with a racist element. I was physically abused as well from one of the crew members

Empty seats next to me - wish it had been for a longer flight!!

I’m grateful for the KLM Air France shuttle bus service to Ottawa. However due to construction and other issues related to the chaotic Uber pickup system at YUL, it’s a challenge to find the Kelios bus service to Ottawa. The signs are not clear or even available. No staff to guide passengers. It’s a stressful experience.

At the airport, terrible, I do not want to even remember it. It was too humiliating for a business class passenger.

Flight was ok but lack of communication cost me to literally beg to be put on another flight as connecting flight had departed

They forgot to serve food and the crew was very unfriendly. Never experienced such a bad KLM flight. Usually fly from Toronto. New York was different.

Couldn’t get boarding pass in SLC even with help from a redcoat, so had to find a desk in AMS to get boarding pass. Technical problems so not sure why. Very inconvenient. The KLM app is not as user friendly as most apps. Also had to wait almost an hour on the tarmac for a fuel truck, which caused us to miss a connecting bus in LUX.

WiFi didn’t exist , seats were super cramped, lights stayed on near my seat for a long time while others were dimmed, the food/trash/drink cart hit my shoulder at least a couple of times while moving, food options were down to just one option by the time it got to my row, the utensils were garbage (knife bent at a couple of places by the time I was done eating) the spoon was very flimsy plastic

Friendliest Flight Attendant I’ve seen since I flew on Southwest Airlines. The whole trip was outstanding…and arrived Early!

It was good overall except from Omaha to Denver when flight a was a repeatedly delayed apparently due to some issue at Denver. Communications could have been handled better. I had to board then deboard with luggage and board again

I didn’t have a seat assignment and my seat was very dirty on the flight from Frankfurt to Budapest.

Left an hour and a half after the listed time. Up side was it had TV screens on the seat.

No screens or meal options. Freezing cold. Dirty seats. Left late.

O’hsre taxi and deboarding took 40 minutes. Needed 20 minutes extra time between connecting flights to avoid running through terminal.

Cree was organized and pleasant. Plane had good seating but as it’s a shuttle toilets hadn’t been thoroughly cleaned (eg. bins too full)

I liked that my son and I were reseated next to each other (we had different bookings). I liked that it was a directg flight and mostly on time. I liked that you provided pillows and blankets. Flight attendants were generally courteous. The messaging through wifi did not work well. The food was not good. Seats are very narrow and I felt slightly claustraphobic in the window seat.

Overall a good experience, but no wifi available for free or for purchase and we got wet from condensation or other water source during descent.

They did not let us board because one member needed a transit visa, which was not evident at the time of ticket purchase.

I was charge a baggage checking fee $68!! I volunteered to check my duffle bag which usually goes under my seat!

I did not like anything because the flight was cancelled yesterday and I did not get to arrive on time in Toronto as I was rebooked with another airline. This caused me to be really stressed out as I am an individual with back injury and to be forced to stay longer in an airport to accommodate a change of airline and the transfers associated with it Due to this I am probably not going to book through your website to eliminate this potentially chaos in the future

shittiest airline in the hemisphere. To improve - start thinking you're flying people, not cattle

Easy boarding, inflight refreshments came on time and comfortable seat

It was good that our flight left early. It was a nice smooth flight and landing.

All good……but luggage didn’t make it on the airplane. Had to wait 3 days. Was a bummer.

Small suitcase used for carryon the last time was refused by boarding crew this time. Appears to be at the discretion and mood of the person on the day. Flight was only half booked, there would have been no problem with space.

It was a problem because there was a delay where we sat before taking off from newark,then when landed in Toronto we sat on tarmac and they wouldn't let us out for a long period of time. When we finally were released to the airport in Toronto the attendant scanned our boarding pass that we were here for our connection to Brazil. We ran all the way to the gate and they said at the gate the door is shut so we can not let you on the plane. We explained that we were checked in by the attendant when we arrived at Toronto airport to go to Brazil and they should not have shut the door. We were ignored at the gate

Flight home was delayed multiple times, did not get home until 2am

Definitely get premium economy on a flight this long if you can. Your legs and while body will thank you.

Flight was delayed by several hours and then cancelled due to weather. But Staff was very helpful getting me on a different flight. United should offer food coupons and tooth brush and paste for stranded passengers

I upgraded to the business class cabin. It was the poorest business class I have ever experienced. No access to any business lounge in Tampa airport. Seats are not comfortable. I had a window seat and had to step/crawl over the next seat. Food was mediocre and service below average for business class. Bathroom location was ridiculous. No place to wait. I cannot believe I paid this kind of money and will never fly Lufthansa Discover again. They really should reimburse me somehow.

Boarding was disorganized. The door to one to the toilets wouldn’t lock. The plane was shockingly cramped, and clearly used for domestic flights due to the menus for items to sell domestic travelers. United should be ashamed of its small seats, tiny unclean toilets, and money grubbing stance toward services, compared to Lufthansa, Emirates, and most international carriers United is awful.

Was never allowed on and not refunded the full amount of the ticket plus charged a $300 processing fee.

Terrible. Lost our luggage for 4 days. Did not advise passengers there was a strike in Barcelona Airport and had zero personnel on hand at airport to advise passengers on where to go to file claims. We had to fend for ourselves. No assistance at all other than an online claims submission process that we had to find out about on our own.

Lufthansa cancelled our flight from Los Angeles to Naples Italy on March 10 for scheduled flight on March 12 Very stressful experience trying to arrange alternatives. Will never fly again with Lufthansa

Everything could have been better. What needed to be wrong with United went wrong

The staff was bit rude when I asked for an extra drink after one beer, asked for one wine glass.

Very good, i got two seats for myself, and was comfortable with the blanket i got

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

Information on your arrival and departure airports