SEA - OPO

$384 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 2/18. 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, 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
$479
Overall average: $976
Multiple Airlines
Mon 12/1Wed 12/10
SEA - OPO • 1 stop
Cheapest one-way
$384
Overall average: $574
Multiple Airlines
Wed 2/18
SEA - OPO • 2 stops
Top airlines
United Airlines
Cheapest • from $488 (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 25% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
October
Cheapest • 28% price drop
April
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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KAYAK searches 100s of sites at once to find you the best travel deals.
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

Mon, Dec 1 - Wed, Dec 10
Multiple Airlines Logo
2:05 pm - 10:30 amSEA-OPO
36h 25m1 stop
Multiple Airlines Logo
4:10 pm - 11:50 amOPO-SEA
27h 40m1 stop
$479Multiple Airlines
Find Deal
Sat, Feb 21 - Sat, Feb 28
United Airlines Logo
6:45 am - 9:30 amSEA-OPO
18h 45m2 stops
United Airlines Logo
6:00 am - 10:43 pmOPO-SEA
24h 43m2 stops
$488United Airlines
Find Deal
Sat, Feb 21 - Sat, Feb 28
Lufthansa Logo
2:00 pm - 10:25 pmSEA-OPO
24h 25m1 stop
Lufthansa Logo
6:00 am - 7:03 pmOPO-SEA
21h 03m2 stops
$494Lufthansa
Find Deal
Mon, Dec 1 - Wed, Dec 10
United Airlines Logo
2:00 pm - 2:55 pmSEA-OPO
16h 55m1 stop
United Airlines Logo
6:00 am - 8:54 pmOPO-SEA
22h 54m2 stops
$499United Airlines
Find Deal
Mon, Dec 1 - Wed, Dec 10
Lufthansa Logo
2:00 pm - 2:55 pmSEA-OPO
16h 55m1 stop
Lufthansa Logo
4:15 pm - 12:10 pmOPO-SEA
27h 55m1 stop
$503Lufthansa
Find Deal
Mon, Dec 1 - Wed, Dec 10
United Airlines Logo
8:10 am - 2:55 pmSEA-OPO
22h 45m2 stops
United Airlines Logo
12:30 pm - 6:32 pmOPO-SEA
38h 02m2 stops
$505United Airlines
Find Deal
Thu, Feb 26 - Thu, Mar 12
Delta Logo
3:05 pm - 10:30 amSEA-OPO
35h 25m1 stop
Delta Logo
6:35 am - 12:35 pmOPO-SEA
37h 00m1 stop
$533Delta
Find Deal
Thu, Feb 26 - Thu, Mar 12
Delta Logo
9:49 am - 3:25 pmSEA-OPO
21h 36m2 stops
Delta Logo
6:35 am - 12:35 pmOPO-SEA
37h 00m1 stop
$537Delta
Find Deal
Sun, Feb 22 - Fri, Mar 20
Turkish Airlines Logo
7:00 pm - 9:50 amSEA-OPO
30h 50m1 stop
Turkish Airlines Logo
10:55 am - 6:05 pmOPO-SEA
38h 10m1 stop
$645Turkish Airlines
Find Deal
Sat, Feb 28 - Sun, Mar 15
British Airways Logo
1:35 pm - 7:15 pmSEA-OPO
21h 40m1 stop
British Airways Logo
8:05 pm - 5:55 pmOPO-SEA
28h 50m1 stop
$655British Airways
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 October, where tickets cost $734 (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 $1,228 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 25% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

Good to know

Low seasonFebruary
Cheapest flight$384
Best time to beat the crowds with an average 15% drop in price.
Most popular time to fly and prices are also 2% 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 $384 for a one-way ticket and $479 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, SkyTeam, and Star Alliance are the airline alliances operating flights between Seattle and Porto, with oneworld 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 $1,026 and an overall rating of 7.7.

  • 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 7999 reviews
8.5Crew
7.9Comfort
7.3Food
8.2Boarding
7.9Entertainment
Airline reviews

I truly love flying with Delta. They have always treated me with the upmost respect

10.0 ExcellentMAYRA, Nov 2025JFK - MIA
Read more Delta reviews

I truly love flying with Delta. They have always treated me with the upmost respect

Our flight attendant in FIRST CLASS was one of the worst I’ve ever had. She was not at all pleasant, nor particularly good at her service.

Everything went well and was good. Nothing exceptional, but no complaints either. Cheap seats are pretty comfortable.

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

They ended up paying for the bag twice, but the counter wouldn't take my baggage receipt. Left it to me to resolve. Not sure how to resolve the issue.

The customer service before board was very rude and when I expressed my concerns about making the connecting flight she laughed and told me I bought the wrong ticket. I explained once it showed the flight was delayed it no longer let me change seats or anything. I was trying to upgrade to make sure I would get to the next gate on time.

Non stop on long haul is the way to go. Great experience

The aircraft interior is old and tired on this aircraft. The entertainment system never worked despite the crews attempt to reset the system.

The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.

Old plane and old configuration/seats but still comfortable for a morning flight

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.

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!

Short flight but an "eager to help" crew made the journey more enjoyable!

Flight was delayed only slightly before takeoff due to traffic control. However, the flight arrived early to ORD. Good flight. United has been very reliable for me.

The person I bought the ticket for didn’t make the flight.

Lately I like the planes have been exceptionally filthy. There’s lines of dust and dirt all across the ceiling in the vents, and the cracks in between the seats are literally full of food. It’s definitely not the quality of service that I was used to with United. I’m also very disappointed with the Wi-Fi! All I wanna do is knock out a few work jobs while I’m trapped in my seat And it spools so bad. They did provide me with a refund, but the process of getting that refund is so complicated. It’s unfortunate.

Another delayed flight. When the delays exceed the duration of the flight, it’s a problem.

Excellent flight. Smooth, efficient boarding. Quick flight. Arrived early at STL.

After boarding the plane in Chicago, the passengers were told that there was a technical problem with the plane. Passengers remained on the plane as they tried to fix the problem. After what was probably an hour passengers were told that there was a need to change planes as the problem was not solved. Passengers disembarked and boarded another plane. After taxing to the runway and waiting for takeoff, passengers were told that owing to the thunderstorm the flight was unable to take off but would try and reroute. After some time passengers were told there wasn't enough fuel for the new route and the plane had to return to the gate for additional fuel. after another log delay the flight got underway. On the plane there was food, drinks, ice or entertainment. We were a glass of water, which appeared rationed. Flight arrived about 5 hours late. The pilot was fantastic and communicated with the passengers throughout the ordeal.

Same as last comment. Food sucks. Quality. Not surprising most people have no clue about nourishment Clearly

Not the fault of United—weather, reroute around weather, time sitting on tarmac, arrived couple hours late, too late for train into city necessitating a much pricier cab but weather…can’t be helped.

Friendly and professional flight crew. Aside from departure delay after boarding, easy flight and smooth landing.

My flight was canceled 1 minute before boarding. The customer service was owful, no one could tell us what was going happened. I spent 30hrs instead of 15 from Washington DC to Brussels. No apologie or help

Boeing 777 is a bad choice for a such a long flight.

The staff at IST airport could have been more helpful. Too much wasted time and the plane from IST to KHI was just horrible. The plane was not clean and smelled bad!

This is my 2nd time with the Turkish airline. Would definitely recommend. In stability we connected to Indiago would not recommend, very cramped seating. No inflight entertainment..service was inferior.

I wouldn't know what the flight was like. AI canceled my flight reservation!! There's no way to speak to an actual human to fix the issue! NEVER AGAIN! ALWAYS BOOK YOUR FLIGHT DIRECTLY WITH THE AIRLINE NEVER GO THROUGH KAYAK OR JUSTFLY.COM!!

Paying extra for premium seats was wasted. Turkish Airlines takes 2 seats for bassinet. The lady next to me had a baby with bassinet Bassinet was in front of my seat

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 booked extra leg room, due to seat neighbor i now consider extra shoulder and arm room as well. Seems like the seats shrink in width now The crew was very friendly and professional ( 100%). Food was good not great, breakfast was bad, a dry slice of bread would have been better. Facilities clean.

Luggage transfer in Chicago was not performed in time. I received my luggage at my destination two days later.

love the crews and my only problem was the delay at Frankfurt was very bad. I have travelled with Lufthansa for over 30 years now and this was cost me some planned business appointment

The flight delay made the connection a bit tight but that's outside the flight crew's control.

We just made it to our connecting flight. A long, long speed walk!

We didn't get the coffee with breakfast in the morning.. 30 mins lazer I asked flight attendant why don't we get coffee now at least.. after the breakfast..she said that captain announced possible turbulences fee minutes ago, which didn't ecplain why we didn't get it with the breakfast..breakfast was very poor btw..just little pastry which you can eat in 4 little bites. Turbulences fortunately didn't even happen.. but we didn't get that more than necessary coffee in the morning after the night flight with very poor sleep.. They just served breakfast 1 hour afzer we took off..at like 11 PM.. that doesn't make sense at all.. Also, flight attendants weren't very nice..they looked like they're not happy with their job.. :/

Lufthansa still has a good level of quality compared to US airlines, especially with respect to (1) food quality - actually tasty, (2) good French red wine - free, (3) good movie selection. Also my ticket price includes 1 free check-in luggage, while some other budget airlines sneak in an extra $150 for a checkin.

I think they overbooked Frankfurt to New York and bumped me off. This changed my return travel I arrived home about 4 hours late. Almost 24 total travel time Totally unacceptable Would not travel with United

We were moved twice on flights to the point we weren’t even on Lufthansa anymore. We had to fly united. Lost paid extra leg room twice. To top it all off we’re forced to pay $375 and $275, respectively for you luggage that was considered sports luggage. We were told it would be Lufthansa fares l, from the united desk, AND WE DIDN'T EVEN HAVE A LUFTHANSA FLIGHT! I’ll be calling once my trip is over on October 7th to all airlines and Kayak. This was ridiculous!

Everything went smoothly and the staff was very kind. I’m glad I purchased the extra leg room for my long flight; it was totally worth it. We were served 2 meals for a 9 hour flight which I was not expecting and they were very tasty. I appreciated them being vegetarian. Customs line in Munich was long; I had a choice to have a 1 hr 40 min layover or 2 hr 40 min layover; I took the longer layover which I was thankful for because my flight was delayed 30 minutes and there’s a good chance I would have missed my connecting flight. This was my very first international flight and I would fly Discover again without hesitation. Thank you for taking good care of me!

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