SEA - OPO

$271 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 5/7. 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
$681
Typical prices: $1,121-$813
Turkish Airlines
Sun 5/3Tue 5/26
SEA - OPO • 1 stop
Cheapest one-way
$271
Typical prices: $350-$627
Multiple Airlines
Thu 5/7
SEA - OPO • 2 stops
Top airlines
Cheapest • from $681 (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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Top layover airports
Cheapest • Avg $730 (round-trip)
Shortest trip • 14h 07m (one-way)
Insights
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When to book
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 30% compared to booking last minute.
Insights
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Insights
When to travel
Cheapest • 43% price drop
Most popular
Good to know
Good to know
+1
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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

Sun, May 3 - Tue, May 26
Turkish Airlines Logo
7:10 pm - 3:50 pm
SEA
-
OPO
36h 40m
1 stop
Turkish Airlines Logo
4:50 pm - 5:15 pm
OPO
-
SEA
32h 25m
1 stop
$681Turkish Airlines
Thu, Sep 10 - Tue, Sep 22
Turkish Airlines Logo
7:10 pm - 3:40 pm
SEA
-
OPO
36h 30m
1 stop
Turkish Airlines Logo
10:40 am - 5:15 pm
OPO
-
SEA
38h 35m
1 stop
$707Turkish Airlines
Wed, Sep 9 - Wed, Sep 30
Turkish Airlines Logo
7:10 pm - 9:40 am
SEA
-
OPO
30h 30m
1 stop
Turkish Airlines Logo
4:40 pm - 5:15 pm
OPO
-
SEA
32h 35m
1 stop
$711Turkish Airlines
Thu, Apr 23 - Tue, Apr 28
Turkish Airlines Logo
7:10 pm - 9:45 am
SEA
-
OPO
30h 35m
1 stop
Turkish Airlines Logo
10:40 am - 5:15 pm
OPO
-
SEA
38h 35m
1 stop
$717Turkish Airlines
Sun, May 3 - Mon, May 25
Turkish Airlines Logo
7:10 pm - 3:50 pm
SEA
-
OPO
36h 40m
1 stop
Turkish Airlines Logo
10:40 am - 5:15 pm
OPO
-
SEA
38h 35m
1 stop
$720Turkish Airlines
Tue, May 5 - Tue, May 12
Turkish Airlines Logo
7:10 pm - 11:30 pm
SEA
-
OPO
20h 20m
1 stop
Turkish Airlines Logo
4:50 pm - 5:15 pm
OPO
-
SEA
32h 25m
1 stop
$732Turkish Airlines
Thu, Apr 23 - Sun, Apr 26
Turkish Airlines Logo
7:10 pm - 3:40 pm
SEA
-
OPO
36h 30m
1 stop
Turkish Airlines Logo
10:45 am - 5:15 pm
OPO
-
SEA
38h 30m
1 stop
$739Turkish Airlines
Thu, Apr 23 - Sun, Apr 26
Turkish Airlines Logo
7:10 pm - 11:30 pm
SEA
-
OPO
20h 20m
1 stop
Turkish Airlines Logo
10:45 am - 5:15 pm
OPO
-
SEA
38h 30m
1 stop
$740Turkish Airlines
Fri, Apr 24 - Fri, May 1
Turkish Airlines Logo
7:10 pm - 9:45 am
SEA
-
OPO
30h 35m
1 stop
Turkish Airlines Logo
10:40 am - 5:15 pm
OPO
-
SEA
38h 35m
1 stop
$747Turkish Airlines
Mon, May 11 - Mon, May 18
Turkish Airlines Logo
7:10 pm - 9:45 am
SEA
-
OPO
30h 35m
1 stop
Turkish Airlines Logo
4:50 pm - 5:15 pm
OPO
-
SEA
32h 25m
1 stop
$748Turkish 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 May.

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 September, where the average cost of round-trip tickets is $1,436 and $1,029 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 30% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$271
Best time to beat the crowds with an average 44% drop in price.
Most popular time to fly with an average 17% 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 $271 for a one-way ticket and $681 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 $907 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 $895 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 8359 reviews
7.2Food
8.1Boarding
7.8Entertainment
8.5Crew
7.9Comfort
Airline reviews

Long flight but comfortable and not freezing as I have experienced on Hawaiian flights to the islands. They gave us blankets just in case. Nice touch.

8.0 ExcellentLorna, Mar 2026
LAX - LIH
Read more Delta reviews

Long flight but comfortable and not freezing as I have experienced on Hawaiian flights to the islands. They gave us blankets just in case. Nice touch.

I haven’t flown economy in over 20 years but it was not bad. Room by my feet for my bag and seat was roomy enough. Surprised in a good way.

The flight was delayed 90 minutes The Gate was wrong The Restroom on Aircraft was not clean There was a half used water bottle in my seat

Delta is always a wonderful experience. A clean plane and the crew is really friendly.

Too many people are taking up space in the overhead bins with their extra piece of luggage. Since they cannot fit their backpacks or extra luggage piece under the seat in front of them, they store it in the overheads and thus taking up room for other passengers. It wasn’t only one or two persons; more like 12 or 13 passengers.

Excellent service, I love the soft blush pink mood lighting on the 767-400ER during meal service. The overhead gasper vents on the 767-400ER were also very strong with a lot of airflow to keep me comfortable on my flight.

This was the worse experience. They delayed our flight twice and we still had to find another flight to get home sooner which was alos delayed. Also, the flight attendant named Ginny on DL9890 leaving at 4:13pm on 3/23/26 was extremely rude.

I love Delta the flight attendants were personable and the flight arrived 1/2 earlier thanks expected. All a plus. The gate agent was a bit flustered but even with that I still had a good experience. Her supervisor assisted me.

Got to fly my favorite plane, the Boeing 767-400ER, to Milan. The soft blush pink mood lighting during meal service was very beautiful and gorgeous. The service was top-notch, and our flights were on time. I highly recommend Delta.

I am still at the Airport! Delayed Delayed and Delyaed

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.

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.

First of all we couldn’t check in online, then we learn at the airport we were on stand by for KLM’s mistake of overbooking. The seats were not comfy at all. Our luggage got lost.

The business class seat is exceptional. I wish the food is more palatable.

Wonderful in-seat entertainment with seatback screens and huge selection of quality movies. The ability to bluetooth connect headphones was amazing.

the entire flight felt off. The crew seemed uninterested and disengaged. The food service was really bad - overcooked, bland, weird food service. They actually woke us up to serve chicken wraps in the middle of the night, after dinner and before breakfast. Made no sense. Ultimately, I was glad they did though, because the breakfast had been held for so long it was inedible. Eggs, potatoes, sausage - all disgusting. We were asked to "honor" the lavatories for premium customers and stay in our own cabin: this was also strange. So people in economy didn't pay enough to use the closest toilet to them??? It's a toilet. All in all, not the experience I have come to expect from United Airlines. The return flight from Paris to SFO was better, btw.

Smooth and easy boarding, comfortable for the entire 5 hour flight, and the seat back entertainment was great! I appreciated all the features, from location info and maps, movies, the ability to connect with Bluetooth headphones, and good selection of movies. Food was good, normal airline snacks (I didn’t purchase anything)

Overall, the flight was good. Lounge access should be with all business class tickets.

They promise free wi-fi prior to boarding and then once on board you are informed you have to purchase wifi even after being a mileagePlus member.

I've been flying American mostly, and it's been very frustrating. This united flight makes me realize maybe the issue isn't flying, but the airline. United was a significantly better experience. The plane was more comfortable, with a normal amount of leg room (vs the ridiculous reductions AA has made), more comfortable seats, screens to watch movies. It was a much better experience!

Awful. No counter attendants. No dinner offered due to delays.

Horrible service no Wi-Fi connection on both leg of the flight and they are refusing to fix bad service

3 hour delay…. Nearly 2 hours sitting on tarmac. Do better, United. Or at least have the sense to not say “we hope you enjoyed your flight with us” upon disembarking.

The whole plane smelled and felt old. The seats were very uncomfortable. Multiple delays. Extra fees.

Very rude gate attendants in San Francisco who didn’t let me bring my little carry on (smaller than usual size) and after boarding I realized that there still were a lot of overhead compartment space (like a full section available in some spots). That made me lose 30 minutes at my destination at 1am and it could have broken something fragile that I had in it

The most uncomfortable flight I’ve ever been on. I’m only 5,4” and barely had enough room to exist, couldn’t even fully relax my shoulders. Not sure why they bother with snacks. Half a coke and a single cookie?? Wow. Purchasable food looked gross too. Remember when airlines used to treat you like a human being?

Departed Palm Springs over an hour late because there’s only one gate, and it has always delayed by the arriving and departing flight to Toronto and the arriving flight from Vancouver.

I checked a bag and there was only one agent to assist all customers with any issues.

I want to thank Carlos at the Miami AC desk - he was amazing and went over and above to help us out. Thank you Carlos and all the best to you!!! You made our faith in AC feel great! Sincerely, David Cubitt

Flight was canceled due to mechanical issues. After a considerable wait in the queue, Air Canada customer service was very helpful to get us on another flight. I am disappointed to report our rescheduled flight is for three days from now. Three days of extra expenses and inconvenience is unacceptable.

Extremely disappointing. My original Denver–Vancouver–Bangkok itinerary was cancelled due to a crewing issue. I was not proactively supported and had to drive back home after already reaching the airport. Communication was poor throughout, and attempts to contact customer service resulted in being on hold for nearly three hours without reaching anyone. Instead of being rebooked on the same direct routing the following day, I was rerouted onto a much longer itinerary via multiple cities and airlines, which resulted in arriving approximately 30 hours later than scheduled. At Denver airport, there was no visible Air Canada representative available to properly assist. Ground staff offered no real support beyond directing passengers to a phone number. There was no clear communication, no ownership, and no meaningful customer care during a major disruption. The final journey involved three flights instead of the original two, significantly increasing travel time and stress. Overall, the handling of the cancellation and lack of customer support was unacceptable. What could have been better? Clear communication during the cancellation Accessible customer service (phone support that actually answers) Proper in-person assistance at the airport Rebooking onto a comparable routing rather than a significantly longer one

Great setup on both flights except the last flight we got condensed dripping all over me in the last 20 mins of the flight

The last 3 hours it was freezing cold in row 56. Multiple people had their winter coats on and were utilizing the blankets provided by the airline. I also did not have easy access to figure out how to book my food allergy and advance for my meals. Most of everything I received was something I couldn't eat. This needs to be made more accessible. Also, I'm 5'10 which is the average height of the American male. I flew from Philadelphia to Toronto and then to Tokyo and the seats were absolutely unbearable. For that long of a flight it is impossible to get comfortable when doing anything. Flights need to have more space and stop prioritizing costs over people.

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

I hated the FRA Airport. Confusing signage, including the path to Immigration and Security It seems that the airport grew haphazardly over the years. I have been through multiple WW Hubs with much better experiences.

Economy Priority seats are extremely uncomfortable. There is no way to escape the boxed in feeling, particularely because the distance between to rows are too short, the hard edge of the front row is keeping legs confined. There is no elevated place to put your feet. I am of average, European size.

Terrible. Both flights were significantly delayed, no luggage, made me check my small bag when many, many others had much larger carry-ons, not even a bottle of water . . . I will not fly Discover Airlines again.

I was deceived on the Kayak site expecting a ticket, but instead finding a "standby" reservation. When I tried to change the ticket, I paid almost twice the price of the original ticket. Then, the airline refused to give me the reserved seat I had chosen and paid for. I think I deserve a refund for this leg of my trip because I was doubly charged and did not receive what I had paid for. I put in a complaint with Lufthansa because the ticket was sold originally sold as a flight they listed. Someone here needs to take responsibility.

Excellent service; they helped me reschedule so I can fly in an earlier flight

I had a good comfortable seat. There was nearly an hour delay. There was an accident with the champagne, but I was well compensated. These things happen sometimes.

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

Information on your arrival and departure airports