SEA - OPO

$326 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 8/11. 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 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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Cheap Flights from Seattle to Porto

 
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.

Recent round-trip flight deals from Seattle to Porto

KAYAK's recommended round-trip deals from the most popular airlines that fly from Seattle to Porto.
Discover the best prices for you by selecting your travel dates on KAYAK.
American Airlines Logo
1:33 pm - 3:55 pmSEA-OPO
18h 22m2 stops
American Airlines Logo
8:15 am - 9:32 pmOPO-SEA
21h 17m2 stops
$722American Airlines
Find Deal
Tue, Aug 5 - Fri, Aug 22
Air Canada Logo
10:00 am - 9:20 amSEA-OPO
15h 20m2 stops
Air Canada Logo
6:00 am - 10:16 pmOPO-SEA
24h 16m2 stops
$734Air Canada
Find Deal
Wed, Sep 17 - Wed, Sep 24
United Airlines Logo
11:58 am - 9:45 amSEA-OPO
13h 47m1 stop
United Airlines Logo
6:00 am - 11:55 amOPO-SEA
13h 55m1 stop
$802United Airlines
Find Deal
Tue, Aug 5 - Fri, Aug 22
Delta Logo
10:55 am - 3:30 pmSEA-OPO
20h 35m2 stops
Delta Logo
5:00 am - 12:50 pmOPO-SEA
14h 50m1 stop
$819Delta
Find Deal
Wed, Oct 8 - Wed, Oct 29
Delta Logo
11:45 am - 3:30 pmSEA-OPO
19h 45m2 stops
Delta Logo
6:15 am - 11:32 pmOPO-SEA
25h 17m2 stops
$829Delta
Find Deal
Wed, Oct 1 - Wed, Oct 22
United Airlines Logo
7:20 am - 9:35 amSEA-OPO
18h 15m1 stop
United Airlines Logo
12:50 pm - 6:49 pmOPO-SEA
37h 59m2 stops
$959United Airlines
Find Deal
Mon, Jun 9 - Tue, Sep 9
Lufthansa Logo
2:20 pm - 3:45 pmSEA-OPO
17h 25m1 stop
Lufthansa Logo
4:35 pm - 11:55 amOPO-SEA
27h 20m1 stop
$961Lufthansa
Find Deal
Fri, Aug 8 - Sat, Aug 23
Lufthansa Logo
2:15 pm - 10:45 pmSEA-OPO
24h 30m1 stop
Lufthansa Logo
6:00 am - 12:25 pmOPO-SEA
14h 25m1 stop
$983Lufthansa
Find Deal
Sat, May 17 - Sat, May 24
KLM Logo
6:07 pm - 10:15 pmSEA-OPO
20h 08m1 stop
KLM Logo
6:05 am - 3:57 pmOPO-SEA
17h 52m1 stop
$990KLM
Find Deal
Sat, May 17 - Sat, May 24
KLM Logo
5:40 pm - 3:35 pmSEA-OPO
13h 55m1 stop
KLM Logo
7:00 pm - 11:45 amOPO-SEA
24h 45m1 stop
$1,065KLM
Find Deal
Sun, Sep 7 - Sat, Sep 13
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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.

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

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

Your flight ticket price will generally be cheaper if you fly to Porto on a Tuesday and more expensive on a Thursday. On your return trip to Seattle, you should consider flying back on a Monday, and avoid Saturdays for better deals.

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 $769 (return) on average. On the other hand, the most expensive months are June and July, where the average cost of round-trip tickets is $1,320 and $1,264 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 1 week before departure. For the absolute cheapest price, our data suggests you should book 4 weeks before departure.

Good to know

Low seasonDecember
High seasonSeptember
Cheapest flight$326
Best time to beat the crowds but there is an average 11% increase 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 $326 for a one-way ticket and $722 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?

    SkyTeam, oneworld, and Star Alliance 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 $1,109 and an overall rating of 8.0, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $1,075 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.

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.
8.0
DeltaOverall score based on 7934 reviews
8.2Boarding
7.9Entertainment
7.9Comfort
7.3Food
8.5Crew
Airline reviews

Our bag was lost so that made unnecessary chaos On our trip

6.0 GoodBarbara, Apr 2025JFK - FCO
Read more Delta reviews

Our bag was lost so that made unnecessary chaos On our trip

Delta is my preferred airline. I've traveled with them for years. On time in most cases, good communication, easy to use app. Most planes are pretty nice. I was on a CRJ 700/900 however, which was pretty badly aged inside and needed a refresh. No infotainment, unreliable wifi, best to download before boarding or bring a book. Food choices are really just snacks on this flight, nice variety but about what you'd expect. Great staff and prompt in departure and early arrival too. Overall quite satisfied.

Crew was friendly Love the entertainment in the seat head rest.

Delta flight was on time, seats were comfortable, and crew was nice.

This had nothing to do with Delta… The flights were on time and flawless. The service was excellent. We purchased seats in (aisle/middle) comfort plus since this was a cross country flight. Unfortunately, the woman seated at the window was 300+ pounds and, as might be expected, covered up about a third of the middle seat also. there was absolutely nothing that Delta could have done about that… I just don’t know what the answer should be. If you purchase a seat, you should should be able to use the entire seat and not just the portion that someone else is not sitting/oozing in. Disappointing…there should be something that could be done….I'm just not sure what solution could be.

Delayed take-off. Very small plane so very scary with lots of bumps during the flight. Would never fly Delta on short flights in small 80 seaters plane again! Felt relieved when landed.

The worst part was I was NOT allowed in the lounge even though I was holding a first class ticket and have a premium American Express card. I have flown Business or First Class with many airlines. Delta is the ONLY one who does not extend this courtesy to anyone except people who hold the very expensive American Express card. As a result, I won’t fly Delta if I have any other choice.

It was an overnight flight and I desperately needed coffee before we landed, but Delta does only one beverage service, and that is shortly after takeoff, not before landing at 5 am.

A little bumpy ride . No food was being provided due the the turbulence. That was ok it was a short flight to my standards.

Simply outstanding. Their new lounge for Delta One customers is a cut above the rest.

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.

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.

You should not have to pay for WiFi in business class

Transfer at Amsterdam airport is very convenient and the airport is easy to navigate. Boarding was also quick and easy. Cabin crew were excellent and the meals were good, although lacking in options.

Overall very positive. Boarding was quick and organized. Cabin was clean and seats were reasonably comfortable. Cabin crew was excellent and the meals provided were also of good quality

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.

Everything is good except the dinner and breakfast. The sandwich is very delicious. Toilet is clean, I only use one of them. Flight attendants are very nice. 👍👍

A bit rush for transit. Food and entertainment are not available

Boarding was a little difficult. The gate area at O'Hare was very small and crowded due to multiple gates in the area. Could not hear the intercom, so had to rely on signage to see when my group was boarding and the signage was blocked by passengers standing in the gate. Flight was great and we arrived in Montreal on time.

Multiple delays and not straight answer from the United team

For economy, it was very good. Staff was great, they even let some of us change seats for more leg room... Put an empty seat between us which was fantastic for a 12hr flight. Onboard entertainment was excellent, I think over 200 choices of movies/tv/etc The bad was the barely/nonfunctional wifi that cost either $16.99 or 1700 miles (full flight). It was atrocious... Definitely the worst of the last 3 long haul major airlines I was on the last few months.

Stewardess spilled orange juice on my clothes/seat no help no apology just threw napkins at me to clean the mess up. Not Happy.

Smooth flight. Boarding was chaotic. Could not hear the gate agent over the intercom. People were lined up in the wrong lines. Groups one and two were told to board through line one and group 3 through line 2. All very confusing. Once in the air, the flight was smooth. There was no entertainment option on this aircraft, even though it was a larger aircraft.

The plane pushed back from the gate on time. However, it stopped on the ramp, and we waited for over 20 minutes before the aircraft pulled back to the gate. Apparently, something of importance had to be removed from the aircraft by the gate agent. I found this to be odd. The delay was not significant, but I felt that whatever was on the aircraft that had to be taken off, should’ve been done before we pushed back from the gate.

I didn’t get on plane. Passport being processed by consulate with visa application. Tried to cancel through underpricer after purchasing cacelling for any reason. No dice, they are thieves.

Electric plugs didn't work. Entertainment system wasn't working

Very punctual, the onboard staff was friendly and correct, the flight was fortunately very calm, the toilets were clean, in short, an excellent experience Thanks

Ordered Vegan meal - it was ok, but not exceptional. Seat ok row 39 middle section aisle. Nearly full flight - crew was busy but they did the best they could. There was a USB A port at the seat. I listened to my own music and only looked at flight information. One nice thing was the connection information was made available in the screen.

Very nice and friendly crew. Boarding system can be improved.

The Etickets had been changed (Why?) without notice ; Hence, that caused troubles when checking in. Not until I contacted my ticket agent and was given correct Etickets could I then check in.

Cleanliness of seats, trays, storage pockets need more attention, but everything else was good.

A great airline, no complaints at all. My experience with Cheap Tickets was very disappointing however. Two hours after purchasing the flight they called to tell me that the ticket price had gone up. I’ve never heard of such a thing. That is called false advertising; I will never use this ticketing service again and will warn all friends to never use it.

One of the worst check in process at the DIA as well as the boarding counter Changed seat at the last minute and assigned middle seat while I paid for window seat. Requested many times but to no avail . horrible customer service and very poor process Requesting refund for seat that was changed last minute

Good overall flight. Excellent crew. Food options could be improved.

Vegan food tasted good. Restroom could be kept cleaner. Seat tray table was a bit tilted so food tray kept sliding down a bit. Flight crew can be a little more friendly, caring and approachable. Their faces lacked smiles and tone was stern.

Flight was delayed then we had to redirect for medical emergency during which time we had no information on what is the plan. The connecting flight was also delayed.

The row of seats were so cramped it was difficult to get in and out of your seat. I even upgraded. A long flight and sad accommodations 😵‍💫 the shorter flight was very comfortable and the seating was spacious

I bought a ticket and paid for for our luggage but I had to pay for my luggage again. I’m so disappointed! We had a 30 min delay and because of that we missed our connecting flight and were told that we would be on the next flight (9am flight ) but we were landed we were booked at 12pm flight. I had a little baby w me, it was very stressful. I begged to leave at 10 am at least. I was emailed that we get a voucher but they didn’t work when we were at a breakfast store. I’ve been always happy w Lufthansa but this time was awful.

Good service … bus transfer upon arrival from plane to terminal: atrocious!!!

helpful and friendly. The Lufthanza people I dealt with before my holiday were so unhelpful by comparison.

We had a 1 1/2 hour delay before we left Denver. When we arrive to Frankfort, they didn’t announce that people with connecting flights to exit the plane first. My next flight was already boarding when we we taxiing in to the gate. I waited another 10 minutes to get off the plane. I had to run to catch my next flight. I mean run! I made it with one minute to spare, but my luggage did not. My luggage came two hours later on a different flight.

My flight was late from US to Frankfurt so I missed my connecting flight flight and I had to wait for long to catch the next flight which was very tiring. Otherwise everyone was very nice.

It would have been nice if my luggage had made it onto my connecting flight as well. Now I have to wait for my luggage to be delivered and that might take a while, which certainly put a damper on the entire experience.

Crew was not happy. Very uncomfortable seats. When person leans back in front of you the screen is too close to me. Food was awful.

They lost my luggage and despite all follow ups through emails and phone calls they don’t give me an update

Everything went really well. Snacks could be better and there was no tea/coffee service after dinner. Crew was helpful and friendly.

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

Information on your arrival and departure airports

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