SEA - OPO

$309 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 9/13. 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

Thu, Sep 18 - Wed, Oct 1
Turkish Airlines Logo
12:30 pm - 3:50 pmSEA-OPO
19h 20m1 stop
Turkish Airlines Logo
4:50 pm - 10:35 amOPO-SEA
25h 45m1 stop
$632Turkish Airlines
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Tue, Nov 18 - Thu, Nov 27
 Logo
1:40 pm - 10:30 amSEA-OPO
12h 50m1 stop
 Logo
11:25 am - 1:15 pmOPO-SEA
33h 50m1 stop
Mon, Nov 17 - Thu, Nov 27
 Logo
9:30 am - 10:15 amSEA-OPO
16h 45m2 stops
 Logo
11:25 am - 1:15 pmOPO-SEA
33h 50m1 stop
Sat, Nov 8 - Fri, Nov 21
British Airways Logo
6:50 pm - 7:15 pmSEA-OPO
16h 25m1 stop
British Airways Logo
8:20 am - 11:18 pmOPO-SEA
22h 58m2 stops
$646British Airways
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Sat, Nov 8 - Fri, Nov 21
British Airways Logo
2:46 pm - 7:15 pmSEA-OPO
20h 29m2 stops
British Airways Logo
8:20 am - 11:18 pmOPO-SEA
22h 58m2 stops
$650British Airways
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Tue, Dec 2 - Sun, Dec 7
Iberia Logo
5:24 am - 7:40 amSEA-OPO
18h 16m2 stops
Iberia Logo
8:20 am - 11:15 pmOPO-SEA
22h 55m2 stops
$658Iberia
Find Deal
Wed, Feb 4 - Mon, Feb 16
Iberia Logo
12:27 am - 7:40 amSEA-OPO
23h 13m2 stops
Iberia Logo
8:40 pm - 9:33 amOPO-SEA
20h 53m2 stops
$683Iberia
Find Deal
Tue, Dec 2 - Sun, Dec 7
KLM Logo
1:40 pm - 10:30 amSEA-OPO
12h 50m1 stop
KLM Logo
6:30 am - 8:50 pmOPO-SEA
22h 20m2 stops
$696KLM
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Thu, Feb 5 - Mon, Feb 16
KLM Logo
1:45 pm - 3:25 pmSEA-OPO
17h 40m2 stops
KLM Logo
11:15 am - 11:40 amOPO-SEA
32h 25m1 stop
$717KLM
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Thu, Oct 16 - Thu, Oct 23
Delta Logo
12:45 pm - 3:30 pmSEA-OPO
18h 45m2 stops
Delta Logo
6:30 am - 4:05 pmOPO-SEA
17h 35m1 stop
$771Delta
Find Deal
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.

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 March, where tickets cost $790 (return) on average. On the other hand, the most expensive months are June and May, where the average cost of round-trip tickets is $1,328 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 3 weeks before departure, which saves you about 14% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 12 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$309
Best time to beat the crowds with an average 16% 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 $309 for a one-way ticket and $632 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, SkyTeam, and oneworld 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 $1,063 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 $1,034 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 7981 reviews
8.2Boarding
7.9Comfort
7.9Entertainment
8.5Crew
7.3Food
Airline reviews

Delayed due to thunderstorms and no in-flight service due to rough weather — both of which are out of Delta’s control. Flight was good overall.

10.0 ExcellentLee, Aug 2025ATL - PHL
Read more Delta reviews

Delayed due to thunderstorms and no in-flight service due to rough weather — both of which are out of Delta’s control. Flight was good overall.

The flight attendants in SLC were rude. I arrived 40 minutes early to gate. Ticket said I needed check in for seat assignments and tried check in and attendants said they weren’t doing it. And proceeded to never call me to give me a ticket so when time to board I received the very last seat. Please relay to employees to do their job better..,

On this flight I felt the food offering was not as complete as on previous flights. The tomato salad was a bit off and there was nothing additional such a bread or butter. The breakfast was only one option, so you either ate what they had or ate nothing. The crew was efficient, but most seemed frustrated throughout the flight. The flight arrived early and was obstacle-free, so I’m overall quite happy, but the shine in the rest of the experience just wasn’t there.

The seats got pretty uncomfortable pretty fast. The armrests are bigger than on other planes, so I had less room in the actual seat. My butt hurt by the end of the flight. :/ comfort was the primary issue. The crew were fantastic!

I believe that a four-hour trip should have a meal. Delta had none.

Great flight with Delta! Boarding was quick and easy, the amenities were solid, and the plane was in great shape. The flight attendants had a fun, lively energy while staying professional. All in all, a smooth trip — even managed to catch up on some rest. Thanks, Delta!

I was uncomfortably cold on the plane. Other than that it was uneventful and therefore as enjoyable as a plane ride can be.

There was supposed to be a meal served, but there wasn’t and the major toilet was out of order

They made us board and then deboard due to mechanical issue which delayed the departure by almost 2 hours and we barely made our connecting flight. These quality checks should've been done before boarding not after.

Having to up charge for a seat assignment is not good. Delta can do better

Ad experience - been flying many years with them but they are losing out to other carriers with their service and bagage / seating policy. My 2 12-yo kids were not placed with the parent. Absurdity.

Short flight so it was okay. Nice crew, all very pleasant and professional. We were near the back in row 27 so just as we got our drinks, we started our descent so had to drink very quickly!

The baggage drop-off in Stuttgart is bad: after online check-in you cannot use the automated baggage drop off as indicated on the website. You can use the terminals but have to cue to 1 of three open and slowly working counters to drop the bags. took about 45 minutes wait time.

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.

It is clear that someone knew, and competent, is in charge of food at United Airlines at least for the international flights. I was flying in coach, but the choices of the dinner were excellent. Tasty, and appropriate size. I had the beef, which was a little bit like a shepherds pie, and it was good. Nothing comparable has been served on a United flight in years. It will not be confused with three star food, but it is very good for airline food. Even better was the breakfast choice between a cinnamon roll and a breakfast sandwich. I chose the breakfast sandwich which was absolutely delicious and which I would happily order again at my local Starbucks or Panera. It is clear that someone knew indifferent is in charge of the food and it’s about time.

The flight was comfortable with the exit row and great service

Had to cancel first flight because Airporter Bus took over 3 hrs to get to airport which resulted in an extra $378 dollar fare . Is there anyway I can be reimbursed for initial fare since it was not my fault? Sent from my iPhone EJ Ledet

Plane was crowded and even when we hit altitude, the plane was hot, not enough air flow.

Flight attendant in first class gave poor service (like he didn't want to be there) and food was awful. We sat waiting for gate upon arrival over 45 mins.

The pilots were late and it made us 1 hour late. The meat was tough and bok choy was also tough.

Flight was delayed 3 hours. No food and drink vouchers was provided. They offered a mini pretzel bag and water .

Stuck on tarmac for two hours plus a 5.5 hour flight. Rude flight attendant. And no meals, not even for purchase!

The service was good, the food could have been better.

Staff was rude. Didn’t give water for 2 hours. Worst service

The crew were very hospitable and pleasant. The food was pretty good. Unfortunately, there was a flight delay of more than 2 hours. We're not sure why but it appeared to be outside the control of Turkish Airlines.

Bough tickets with luggage, but made me pay at Airport as well

The economy seat was so uncomfortable, had not enough leg room for 13 hours flight, front seat basket was broken and couldn’t hold anything, food quality was horrible( we got food poisoned ) we charged for logged which used to be free. We paid too much for this flight and very disappointed. Turkish air line better to make satisfy and respect people instead of find different way to scam people.

This is really the rating of two flights. JFK to IST then IST to NQZ. New York to Istanbul was good. Good crew and all positives. The flight to Astana was so bad that brought it all down. Crew was nonexistent above the minimum, seats were cramped, and it was hot on the plane. Turkish Airlines seems to be slipping down to US based carriers level.

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.

Flight was late arriving. So, we left 25 min late. Pilot made some time up during the flight. Therefore, we arrived alittle past original time.

Food is too little (in volume) and too spicy.. There are no snacks in the back of the plane in between meals.

The seat I was stuck in was so unimaginably uncomfortable. I have never had that tight of a seat in my 20 years of flying. Even budget airlines give you more space.

We were upgraded to economy plus and everything was awesome!

I liked the crews attentiveness, all food and drink items were tasty, and came out in a timely manner. The entertainment systems were not as responsive and my seat had issues with the auxiliary for the headphones. Seats were OK, and the headrest for my seat could go back only so far. Bathrooms were tight fit.

Our flight was delayed for over an hour due to weather, and it had already been a long travel day. However, the crew was calm and compassionate, listening to every complaint with genuine concern. They got us home safely without incident, in spite of all of the obstacles. I’m grateful.

Hate their old flights, boatding, food and services. Very poor quality

Insulting. Lufthansa flight from Munich to EWR had us getting our luggage when we were told in Florence that it would follow us to Indianapolis. It did not. Then very slow security in EWR caused me and three other passengers from Lufthansa flight from Munich to miss the boarding closure. Behind me were two elderly grandparents and their ten year old grandson. We were all refused entry on a plane to Indy that was still at the gate. The doors had not even closed inside the terminal yet. No apologies or compensation offered. Not even a meal voucher let alone a free hotel stay for our inconvenience. I m not sure what the other three passengers behind me did ( they were elderly with a grandson, recall), but I stated 12 hours overnight in a chilly EWR airport until next flight to Indy at 850 next morning.

The food could be better, more snacks. And have some plugs to chargue the phone.

The pasta in the evening meal was tasteless. Otherwise, the flight was okay.

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

Information on your arrival and departure airports

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