SEA - OPO

$260 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 10/14. 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

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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 (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, Oct 26 - Mon, Nov 3
United Airlines Logo
8:00 am - 9:30 amSEA-OPO
18h 30m2 stops
United Airlines Logo
12:30 pm - 12:10 pmOPO-SEA
31h 40m1 stop
$604United Airlines
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Wed, Oct 22 - Mon, Nov 3
Lufthansa Logo
6:50 pm - 11:20 pmSEA-OPO
20h 30m1 stop
Lufthansa Logo
12:30 pm - 12:10 pmOPO-SEA
31h 40m1 stop
$617Lufthansa
Find Deal
Wed, Oct 22 - Mon, Nov 3
United Airlines Logo
10:00 am - 11:20 amSEA-OPO
17h 20m2 stops
United Airlines Logo
12:30 pm - 12:10 pmOPO-SEA
31h 40m1 stop
$621United Airlines
Find Deal
Wed, Sep 24 - Wed, Oct 8
Turkish Airlines Logo
7:10 pm - 9:45 amSEA-OPO
30h 35m1 stop
Turkish Airlines Logo
10:50 am - 10:35 amOPO-SEA
31h 45m1 stop
$647Turkish Airlines
Find Deal
Wed, Oct 22 - Sun, Nov 2
Air Canada Logo
5:30 am - 11:25 amSEA-OPO
45h 55m2 stops
Air Canada Logo
5:15 am - 7:16 pmOPO-SEA
21h 01m2 stops
$656Air Canada
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Wed, Oct 22 - Sun, Nov 2
Lufthansa Logo
6:50 pm - 11:20 pmSEA-OPO
20h 30m1 stop
Lufthansa Logo
5:15 am - 1:20 pmOPO-SEA
15h 05m1 stop
$659Lufthansa
Find Deal
Wed, Oct 1 - Wed, Oct 8
Turkish Airlines Logo
7:10 pm - 3:50 pmSEA-OPO
36h 40m1 stop
Turkish Airlines Logo
10:50 am - 5:15 pmOPO-SEA
38h 25m1 stop
$663Turkish Airlines
Find Deal
Wed, Oct 22 - Thu, Oct 30
Air Canada Logo
10:00 am - 11:25 amSEA-OPO
41h 25m2 stops
Air Canada Logo
6:00 am - 9:56 pmOPO-SEA
46h 56m2 stops
$682Air Canada
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Wed, Oct 22 - Wed, Oct 29
Delta Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
Delta Logo
11:45 am - 10:56 amOPO-SEA
30h 11m2 stops
$703Delta
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Wed, Oct 22 - Thu, Oct 30
Delta Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
Delta Logo
11:45 am - 10:48 pmOPO-SEA
42h 03m2 stops
$715Delta
Find Deal
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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 May, where the average cost of round-trip tickets is $1,336 and $1,226 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 24 weeks before departure.

Good to know

Low seasonFebruary
High seasonApril
Cheapest flight$260
Best time to beat the crowds with an average 13% drop in price.
Most popular time to fly and prices are also 4% lower on average.
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 $260 for a one-way ticket and $604 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?

    oneworld, 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 $1,065 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 $1,002 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.
8.0
DeltaOverall score based on 7975 reviews
7.9Comfort
8.5Crew
7.3Food
8.2Boarding
7.9Entertainment
Airline reviews

My husband upgraded our seats and I don't know if it was due to the type of planet was or if they didn't upgrade our seats. We were supposed to be in I believe comfort seats and they were just as tight as any other seat- no leg room and we are very tall people but at least it wasn't extremely cold. My husband did put in a complaint about our seating because he paid extra and if we would have known that the space and the tightness would have been the same, we just would have gotten the emergency row emergency row seats that we normally get. We love Delta but both our flights coming home we're not good. Oh I forgot to mention that on our flight to Hawaii our luggage wheels got broke and we had to purse new luggage on vacation then we never had this problem so we didn't know protocol and reported it after we got home only for them to tell is we only had 24hrs to report the damage. Not sure what was going on with Delta this vacation trip.

4.0 OkayMrs., Jul 2025LAX - RDU
Read more Delta reviews

My husband upgraded our seats and I don't know if it was due to the type of planet was or if they didn't upgrade our seats. We were supposed to be in I believe comfort seats and they were just as tight as any other seat- no leg room and we are very tall people but at least it wasn't extremely cold. My husband did put in a complaint about our seating because he paid extra and if we would have known that the space and the tightness would have been the same, we just would have gotten the emergency row emergency row seats that we normally get. We love Delta but both our flights coming home we're not good. Oh I forgot to mention that on our flight to Hawaii our luggage wheels got broke and we had to purse new luggage on vacation then we never had this problem so we didn't know protocol and reported it after we got home only for them to tell is we only had 24hrs to report the damage. Not sure what was going on with Delta this vacation trip.

My flight was extremely cold. I had a jacket and a cover was left in each seat. The cover was extremely thin and I have a disability, fibromyalgia and arthrithis and AC air is the worst. I closed my vent and my husbands vent and it still was frigid. I asked the attendant if I could get another cover and she quickly almost dismissively and totally unconcerned stating, (I quote) (one per chair) and walked off so quickly that I didn't get a chance to explain to her that I literally have adisability. I didnt want to make a seen so I set on that flight for over 5 hours in pain, joints locking up and extremely uncomfortable. When my fibromyalgia flares up my joints not only ache but they will lock up also and it takes me days to get back to my regular self even though I take medication for it. I felt like it would not have hurt anyone at all for her to just give me an extra cover because I'm sure they have all types of medical issues in people that fly every day.

After all the weather issues at least they got me to my destination the next day

My flight was canceled after being rescheduled for four days canceling my trip. Kayak and everyone affiliated with it I.e the airlines, and just fly have been excruciating to deal with. My trip to visit family had to be canceled as there was no way to make it. I am furious at all of you.

They delayed our flight because of bad weather in NY which was completely understandable. Then they cancelled our flight and a later flight that evening. The earliest we could fly was the next morning. We ended up buying last minute tickets on another airline and made it home slightly delayed but safely that evening. Delta kept saying it was weather related but if that was the case how did we make it back on another airline? The weather in NY was cloudy but not bad.

From Atlanta to Savannah - flight connection was way to short (we weren't even late landing ) and flight was already boarding when we landed - we were told we were the last on board and so we had to gate check our bags. Once we got on the plane, there were at least seven open bag spots so that was unnecessary delay. There should be better communication between the gate agent and the crew.

Crew was excellent. Comfort seats not as nice as other kinds of planes.

Not a "Delta" issue, but a JFK issue: We booked a connecting flight with 3 1/2 hours between to clearn immigration and customs. Our inbound flight (BCN to JFK) was on the taxiway 45 minutes which ate into our layover time. Immigtration was insanely quick with the CBP MPC app; however, clearing TSA (again, after we were ALREADY cleared in Spain on the inbound international flight) took over 95 minutes. This left us with 10 minutes before boarding the connecting flight (JFK to SAN) to walk to the far end of Terminal 4 and try to find food. We didn't find any food that could promise to serve us in under 10 minutes so we boarded the Delta flight after coming off a plance and an 8-hour flight knowing that we wouldn't be served any food on the next 5 1/2 hour flight. I feel like Delta needs to put pressure on the JFK TSA to open more screening stations (by our count, we saw only 5 scanners open and a line of - as we said - over 90 minutes. The insult is that we WERE ALREADY SCREENED through TSA, but as you come off one flight into the USA, you have to go through the whole process again. It seems like if you have a connecting flight, there should be a way to pass through immigration and customs without needing to return through TSA.

It was a great flight and the stewards and stewardess were all kind and accommodating!! The seats were comfortable and entertainment screen excellent!

There are 4 flights in consecutive gates with about the same departure time. Two flights were boarding at the same time. One was delayed or boarding would be happening at the same time. I am not sure what Delta and LAX need to do to have a better layout at the end of Terminal 2

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!

The service was great. However the lounge only gets passing grade

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 professional, polite and friendly, boarding was seemless, but come on KLM surely you can do better than a pack of cheesy biscuits as an inflight snack

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

We love united ! We would like to acknowledge Aimee in the lounge near gate 130

Boarded plane and then delayed 1.5 hours while on the plane

Although the flight was delayed the crew and the flight itself were very good. Couldn't fault anything and after the disappointment of being abandoned in the US by BA it was a welcome relief to travel with United

Survey sent before we actually left. Delay after delay. Now a crew problem.

I love flying with United. Unfortunately, I flew on an older plane with minimal upgraded technology (no Bluetooth functionality or handy charging ports). Otherwise, the flight was great and even arrived early.

They changed my seats after I checked in and I was stressed from the time I saw that information until just before boarding, when the gate attendant fixed it, but it shouldn't have happened. And if it couldn't be prevented, then the people on the phone I spoke with should have done something to help, which they did not, nor did they offer me compensation, just meaningless apologies.

online check in was not available so i had to get to airport extra early. The flight was delayed and my luggage was lost. I had an argument with the person behind me who wanted to keep her bag on the floor and not allow my seat to recline on a 9hr plus flight. So overall, lots and lots of areas for improvement.

Horrific. They missed my connecting flight to San Diego. I didn’t get there until Monday at 9am when I had a mandatory court settlement conference scheduled at 6am since we had parties on the east coast. This caused many issues. All because United apparently forgot to hold the doors open until my flight landed that only had a 10 minute delay. This was the last flight to Southern California. So I couldn’t even rent a car to finish the trip. United cannot be trusted when traveling on specific days and times since weather didn’t have anything to do with the delays.

My flight was delayed a very short period of time but they did not hold my connecting flight to San Diego, also through United. So they closed the doors before we got off our plane. They would only have to help the door open for another five to ten minutes. So I missed a court deadline for a manditory mediation settlement conference for my client. I had to get an associate to be there in person and be on the phone with him relaying what he needs to do the entire time. The court was very upset with me and so was my client. United cannot be trusted.

Very rough getting into denver. my kid threw up it was so rough.

The 2 agents on the check in counter were super nice , helpful and very polite. Boarding was like a 1 2 3, I would recommend Turkish airlines for your next trip.

Everything was very good, except that the plane was an hour and a half late

flight with heavy turbulence old boeing 777 rest wasnt clean dashboard doesn’t work

Light and recline did not work on my seat. Very uncomfortable and could not read in the dark

Bad experience; they are not good anymore. They charge too much for luggage seat are so uncomfortable, Flight delays which may miss your next flight, they don’t care if you miss the flight or not. Zero customer services for front desk representatives Istanbul's airport I’m not using this airline any more.

This flight was in the air when the national power outage happened on 28 April 2025 in Spain and Portugal. As a result Lisbon airport was closed and the flight was diverted to Porto. There were no phones, internet or ATMs working and the Turkish Airlines ground crew in Porto were trying to find alternative transport to Lisbon (by bus). This did not materialise until late in the evening. The Turkish Airlines ground crew suggested that passengers may find their own way of getting to Lisbon. That in itself is a failure of Turkish Airlines, but understandable as there were no means of communication. The Turkish Airlines ground crew also said that any expenses insured for travel to Lisbon will be refunded by the Airline through their website. Unfortunately, I could find no way to travel back to Lisbon other than to hitch hike with an Uber driver. Because no systems were available and no credit card payment possible I paid the driver 140 Euros in cash with no receipt as systems were down. I arrived at my Lisbon hotel at 23:30 (flight was scheduled to land at 12:30). Upon contacting Turkish Airlines for compensation they are not willing to do anything as I do not have an invoice for my expenses. They do not even consider the 10 hours of delay and inactivity on their part as a reason to provide any sort of curtesy towards me. I find their behaviour appalling.

I’ve been traveling for 20 years. I tried Turkish airline for the first time horrible horrible service and it would be my last time even if I get offer for a free ticket, I will not accept it. They have races and the worst Flight attendant

It wasn't good. I didn’t understand. They changed 320 dollars for 2 luggage. My ticket was regular and I paid almost 1200.00 dollars. Why they did charge? I want my money back.. thanks Yılmaz polat

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.

We were charged for luggage, and our ticket was with Lufthansa and was supposed to include luggage fees. So our experience was a bit bad. Also, the flight was about 45 minutes late arriving.

Flight was great only departure was delayed to saome ground crew issues

It was freezing. I asked crew member for a blanket and was told it might be in front of plane but I never got one. I turned off all the vents but still froze.

Cheapest airlines I have ever been on. I got downgraded and never got on united. I got rerouted through Vancouver onto jetwesf

Flight was 1.5 hours late to depart so changed flights to Swiss Air.

The United Airlines crew that operated this flight was subpar. They didn’t

Very small and uncomfortable seats, Hard to hear entertainment system sound. Horrible food. Staff doesn't care much about the passengers. 2nd time they didn't give me my vegetarian meal. They asked me regular food with meat. The airline and staff was from United airlines.

Checkin took along timen only.few angents available at.checkin desk. Customer support over phone no existence

At baggage claim, I was given the wrong printed ticket. The ticket belonged to another passenger for a different flight — to Zurich instead of Frankfurt (layover). I was even allowed to pass security, and when I asked the Lufthansa employee if I was on the correct flight, and why it was changed. The employee said everything was correct and I should board. When I got on the plane, there was someone in my seat, and the crew on the plane finally realized that I was on the wrong plane. When I got off the plane, nobody was willing to help, and the security refused to provide my original printed ticket. That was until I showed them that I took a photo of the ticket; once they realized I had photographic evidence, they were suddenly ready to help me. The Lufthansa employee began communicating with other airlines and found a flight that would take me to my destination via Polish Airlines. I was required to once again go through security, re-check my bag, and once again pay for my checked bag and weight overage fees. This experience was incredibly stressful and very frustrating, as you can imagine. A Lufthansa employee told me I would be eligible for a refund. Please tell me what steps I need to take in order to make that happen. Thank you!

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

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