SEA - OPO

$281 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 10/18. 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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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

Tue, Mar 17 - Wed, Apr 1
Multiple Airlines Logo
8:30 am - 9:30 amSEA-OPO
18h 00m2 stops
Multiple Airlines Logo
6:00 am - 7:18 pmOPO-SEA
21h 18m2 stops
$551Multiple Airlines
Find Deal
Tue, Mar 17 - Wed, Apr 1
Lufthansa Logo
3:00 pm - 2:45 pmSEA-OPO
16h 45m1 stop
Lufthansa Logo
6:15 am - 4:59 pmOPO-SEA
18h 44m1 stop
$553Lufthansa
Find Deal
Tue, Mar 17 - Tue, Mar 31
United Airlines Logo
8:30 am - 9:30 amSEA-OPO
18h 00m2 stops
United Airlines Logo
12:00 pm - 9:51 pmOPO-SEA
41h 51m2 stops
$556United Airlines
Find Deal
Tue, Mar 17 - Wed, Apr 1
Lufthansa Logo
3:00 pm - 2:45 pmSEA-OPO
16h 45m1 stop
Lufthansa Logo
6:15 am - 4:59 pmOPO-SEA
18h 44m1 stop
$557Lufthansa
Find Deal
Mon, Jan 19 - Mon, Feb 2
KLM Logo
3:10 pm - 10:30 amSEA-OPO
35h 20m1 stop
KLM Logo
11:25 am - 11:25 amOPO-SEA
32h 00m1 stop
$622KLM
Find Deal
Thu, Oct 16 - Fri, Oct 24
Turkish Airlines Logo
7:10 pm - 9:45 amSEA-OPO
30h 35m1 stop
Turkish Airlines Logo
4:50 pm - 10:35 amOPO-SEA
25h 45m1 stop
$668Turkish Airlines
Find Deal
Fri, Oct 17 - Fri, Oct 24
Delta Logo
5:40 pm - 10:15 pmSEA-OPO
20h 35m1 stop
Delta Logo
9:20 am - 12:18 amOPO-SEA
22h 58m2 stops
$669Delta
Find Deal
Tue, Oct 7 - Mon, Nov 3
KLM Logo
5:40 pm - 7:15 pmSEA-OPO
17h 35m1 stop
KLM Logo
11:25 am - 11:25 amOPO-SEA
32h 00m1 stop
$671KLM
Find Deal
Fri, Oct 31 - Fri, Nov 7
United Airlines Logo
8:00 am - 11:40 amSEA-OPO
20h 40m2 stops
United Airlines Logo
6:00 am - 10:45 pmOPO-SEA
24h 45m2 stops
$742United Airlines
Find Deal
Thu, Nov 27 - Sun, Nov 30
Turkish Airlines Logo
7:00 pm - 9:55 amSEA-OPO
30h 55m1 stop
Turkish Airlines Logo
4:10 pm - 5:05 pmOPO-SEA
32h 55m1 stop
$757Turkish Airlines
Find Deal

Everything you should know

Top airlines
Lufthansa
Cheapest • from $553 (round-trip)
Delta
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to book
3 weeks
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 23% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
March
Cheapest • 24% price drop
April
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Cheapest round-trip
$551
Overall average: $788
Multiple Airlines
Tue 3/17Wed 4/1
SEA - OPO • 2 stops
Cheapest one-way
$281
Typical prices: $508-731
Multiple Airlines
Sat 10/18
SEA - OPO • 2 stops
Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Porto!
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 $788 (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 23% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 24 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$281
Best time to beat the crowds with an average 16% drop in price.
Most popular time to fly and prices are also 3% 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 $281 for a one-way ticket and $551 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 $1,008 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 $1,044 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 7961 reviews
8.5Crew
7.9Entertainment
7.3Food
8.2Boarding
7.9Comfort
Airline reviews

The staff and the boarding procedure were all amazing . The one flight was not equipped with WIFI which now adays seems odd. All in all the experience was good

8.0 ExcellentAnonymous, Sep 2025GFK - MSP
Read more Delta reviews

The staff and the boarding procedure were all amazing . The one flight was not equipped with WIFI which now adays seems odd. All in all the experience was good

Passengers need to check in big baggage instead of bringing on the plane. That cause inconvenience for everyone. Otherwise flight was good.

Perfect flight both ways. On time, courteous staff, plane comfortable and cool. Best domestic flights I’ve had in awhile.

The food was terrible especially for a 15 hour international flight. The crew was unpleasant as well.

Really low quality food especially for an international flight. The crew also was surprisingly unpleasant except couple of ladies. I know we were not in first class but that’s no reason to treat customers as less.

Flight delayed for two and half hours and then canceled altogether due to mechanical issues. No mechanic onsite to fix so had to send one from LAX.

Quick check in. Everything went smooth. I don't know what can be done about airline food.

Crew was good. The reservation got mixed up and they didn't have my TSA number. I am also a Silver Medallion and wasn't able to use Sky Priority.

Delta made it easy, comfortable and timely. The crew was fantastic.

This route with Delta always has delays or is cancelled. Aircrafts seem smaller and older. I fly Delta quite a bit - haven’t had issues with the international flights. But this route has always been the troublesome one

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.

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!

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.

Terrible. They wouldn't allow me on my flight on the 14th..

We had to deboard 2 times due to maintenance issues. They changed the plane, and then we got deviated to LAX due to maibtenance issues on the other plane, had to sleep at LAX and los a full day.

Everything was good, except the seats in economy were so close together, you could barely get out when the seat in front of your was reclined. If the airlines keep jamming in more and more seats, it will become intolerable. I will look for another airline that considers customer comfort and does not keep adding more rows of seats for more profit.

The newer screen was super cool and had the option to watch many different shows or movies. Crew was polite and helpful. However again, many children screaming bloody murder and kicking my seat, and parents doing nothing about it as usual.

Flight was good and crew was super polite. However, there were around 5 kids screaming the WHOLE 2 hours. I understand kids have to come but parents need to do something to control their children. They make the experience terrible, especially after finishing 16 hour shifts at the hospital I needed some sleep, which I did not get.

IAD with the archaic people movers is just a place to be avoided.

Great service on board. Boarding a bit slow due to process. Food was pretty average.

Tastless food and too obvious lack of enthusiasm for service in the economy vesus business class

All of the United employees I interacted with were professional and courteous. The aircraft was clean, the food on the flight was good. No complaints here.

I had no checked baggage but was required to hand over carry on baggage at the door of the plane. There was a lot of overboard space in the plane and I was one of the last ones. I ran to get my carry on but it was gone. I was given back at the plane door in Toronto, so the wait was not as long as it would have been at the carousel.

Rude staff. I would avoid using the word racist but definitely partially or discriminatory. My 72 yrs old mother who is also disabled was traveling on this flight. She was the second passenger boarded to the plane. The First elderly couple ahead of my mother were allowed to use the airplane bathroom but my mother was denied entry stating it was for safety reasons. My mother objected the the couple in front of her were allowed but hostess still stated that due to the flight safety reasons she can’t use it. Even my mother explained that he is using blood pressure medication that’s why she have to use the restroom frequently but the crew continued arguing her. At one point the Mae attendent even suggested that if that’s the case my mother can urinate in her seat. The level of disrespect against an elderly lady is beyond my comprehension. This matter will be taken to the social media to shame the employees involved.

my experience was great with Turkish airlines . the problem i encountered was with kayak booking. When I booked . it showed that im allowed a bag . and when I got to the airport, i had to pay $165 for one bag.

Not up to Business Class standards. Two of the three toilets were out of order. The hostesses were aware and didn’t show any responsible act to do something. Food quality was not what we expect from Turkish hospitality. Overall we were not impressed and disappointed.

During mid flight, try to get a flight attendant to help I couldn’t find one Otherwise, everything was perfect

I was not given basinett seat.The connecting flight was missed due to airline fault i was not accomodated for hotel.Drinks were normt served frewuently.Never travelling again on tirkish airlines.I always travel wiyh family by turkish airline but no more.zero stars

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.

I liked everything BUT the temperature. It was freezing and now I am sick.

I liked Quiet people around me. Crew could have helped people with overhead luggage so they aren't moving other peoples bags around and causing problems for people that had there bags there first

The flight and crew were good. The customer experience on the ground could have been better. We had to reschedule our flight because of a delay on the previous flight. The attendants working the desk in Washington DC were not helpful. They told us to scan a QR code and that would get us rebooked. Why couldn't two people standing at their computers do this? We had to chat with someone to get everything figured out. It was extremely confusing.

The plane was delayed by two hours in Chicago which led to us missing the next flight. Lufthansa rebooked the flight and booked us a hotel for the night in Frankfurt. The level of customer service and getting us taken care of was superb. The flight crew and the service on the ground was superb.

It was a short flight, everything was good with it.

Flight was delayed over one hour and I had to pay to select my seat, even though my booking supposedly had free selection (I paid extra for this at time of booking)

Stop charging for alcohol overseas flights and start taking cash again not everyone wants to pay with card if the person is bigger give him seat on the outside seats not the middle in between the people is common sense and mainly if you fly for Lufthansa provides the sam service and experience...

good entertainment package but rather small seats for business class

The male attendant has zero personality. It seemed like he was over worked or hated his job, not once did he smile or made any contact with the people on the plane. Strictly business and call it a day!

Booked Economy but it translated to economy light for Lufthansa so now we are stuck paying an extra $75 per person both ways for our checked bags. If I had known that, I would have never booked these tickets because it came out to be more than other options. The booking in the kayak side clearly says Economy and has a link to the inormation for Lufthansa which states Economy included a checked bag. Super annoyed about that.

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

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