SEA - OPO

$347 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 3/17. 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, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to Porto, as well as popular online travel agencies
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Everything you should know

Cheapest round-trip
$462
Overall average: $870
Delta
Tue 1/27Tue 2/10
SEA - OPO • 1 stop
Cheapest one-way
$347
Typical prices: $524-$566
Multiple Airlines
Tue 3/17
SEA - OPO • 3 stops
Top airlines
Delta
Cheapest • from $462 (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 32% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
October
Cheapest • 29% price drop
April
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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We hope you love your trip to Porto!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Seattle to Porto (SEA-OPO)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle to Porto that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to Porto

Tue, Jan 27 - Tue, Feb 10
Delta Logo
1:40 pm - 10:30 amSEA-OPO
12h 50m1 stop
Delta Logo
5:00 am - 11:40 amOPO-SEA
14h 40m1 stop
$462Delta
Find Deal
Wed, Jan 28 - Fri, Feb 13
Delta Logo
2:10 pm - 10:25 amSEA-OPO
36h 15m1 stop
Delta Logo
5:00 am - 11:40 amOPO-SEA
14h 40m1 stop
$464Delta
Find Deal
Tue, Jan 27 - Sun, Feb 8
Delta Logo
9:59 pm - 10:30 amSEA-OPO
28h 31m2 stops
Delta Logo
11:15 am - 11:40 amOPO-SEA
32h 25m1 stop
$465Delta
Find Deal
Mon, Jan 12 - Tue, Jan 20
KLM Logo
2:10 pm - 10:30 amSEA-OPO
36h 20m1 stop
KLM Logo
5:00 am - 11:50 amOPO-SEA
14h 50m1 stop
$466KLM
Find Deal
Wed, Jan 28 - Sun, Feb 8
Delta Logo
2:10 pm - 10:25 amSEA-OPO
36h 15m1 stop
Delta Logo
11:15 am - 11:40 amOPO-SEA
32h 25m1 stop
$467Delta
Find Deal
Wed, Jan 14 - Thu, Jan 29
Delta Logo
7:10 am - 10:30 amSEA-OPO
19h 20m2 stops
Delta Logo
5:00 am - 11:50 amOPO-SEA
14h 50m1 stop
$469Delta
Find Deal
Thu, Jan 29 - Fri, Feb 13
Delta Logo
7:10 am - 10:25 amSEA-OPO
19h 15m2 stops
Delta Logo
5:00 am - 11:40 amOPO-SEA
14h 40m1 stop
$472Delta
Find Deal
Tue, Jan 27 - Wed, Feb 11
Delta Logo
7:10 am - 10:30 amSEA-OPO
19h 20m2 stops
Delta Logo
11:25 am - 11:25 amOPO-SEA
32h 00m1 stop
$474Delta
Find Deal
Sun, Feb 1 - Tue, Feb 10
Delta Logo
3:05 pm - 10:30 amSEA-OPO
35h 25m1 stop
Delta Logo
11:15 am - 11:40 amOPO-SEA
32h 25m1 stop
$475Delta
Find Deal
Mon, Jan 12 - Tue, Jan 20
KLM Logo
2:10 pm - 10:30 amSEA-OPO
36h 20m1 stop
KLM Logo
5:00 am - 4:54 pmOPO-SEA
19h 54m2 stops
$476KLM
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 $730 (return) on average. On the other hand, the most expensive months are June and December, where the average cost of round-trip tickets is $1,320 and $1,306 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 32% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 24 weeks before departure.

Good to know

Low seasonFebruary
Cheapest flight$347
Best time to beat the crowds with an average 13% drop in price.
Most popular time to fly and prices are also 1% 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 $347 for a one-way ticket and $462 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?

    SkyTeam, and Star Alliance are the airline alliances operating flights between Seattle and Porto, with SkyTeam 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 7.9, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $1,064 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 8011 reviews
8.1Boarding
8.5Crew
7.9Comfort
7.9Entertainment
7.3Food
Airline reviews

I fly Delta all the time, have Platinum Medallion status. But this route seems to have major problems with delays and seems to never leave on time! Have only taken it twice in the last two weeks, and each time it had delays of more than 1 hour... very disappointed!!!!

4.0 OkayCarl, Dec 2025FLL - LGA
Read more Delta reviews

I fly Delta all the time, have Platinum Medallion status. But this route seems to have major problems with delays and seems to never leave on time! Have only taken it twice in the last two weeks, and each time it had delays of more than 1 hour... very disappointed!!!!

Getting to the flight was arduous and lengthy. The flight itself was good but the food option wasn’t a good selection. I need to do a Kosher option on my return. Flight crew were nice

Good seats in Main cabin, excellent service and excellent landing

My flight was cancelled with no explanation after I had already cleared security. I was given 4 options to rebook, only one being non-stop like I had paid for. I grabbed it. It was 4 plus hours later and then took off even later. Biggest complaint is that I booked early and had an aisle seat. They gave me a "window" seat in front of the exit row, so the seat did not decline. I weigh all of 103 #s and it was tight for me! For what I paid, I feel I was kind of ripped off. I think they should have given me the empty comfort seat for the inconvenience. There was no apology nor any explanation as to why the flight was cancelled. My guess is it benefitted Delta in some way.

Very smooth, on-time, and pleasantly uneventful flight. The team at the gate and on board were professional and genuinely courteous. The pilot kept us well updated throughout, and both takeoff and landing were steady and enjoyable without any drama. Just a good, solid flight. Thank you! 💗

Staff was exceptional! Everyone was kind, professional and friendly making the trip very pleasant. Thank you!

No lunch on a x-country flight scheduled for 10:50 am departure, arrived 5+ hrs later. That requires a black box label before you pay for the tickets. Worst, when I checked in online, it's specifically said that lunch was served on his flight for economy Plus passengers.

We had a lot of really rough weather but that was not Delta's fault. Pilot was amazing.

First, Delta needs more flights to/from Miami. Second, a 1000pm leaving at 1230pm is unacceptable from their biggest airport world hub. Another aircraft could have been used such as the aircraft scheduled to be used in the morning for that exact same route. Yes, I did get me there but the lack of sleep the next day didn't help me enjoy my entire trip since I was busy with activities during the weekend. This can be and is expected from Spirit (going bankrupt) and Frontier (despite they're nickel and dimers). But from Delta's World Hub? That's totally unacceptable!

This flight was straightforward and without difficulty. Service was OK, but I continue to be underwhelmed by level of attention given to Sky Priority passengers.

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!

Flight was delayed 8 times. We were sitting at the airport for 14 hours. We got 2 hours of sleep (if that) on what was not meant to be a red-eye.

The movies offered were great. Staff were very pleasant and very efficient.

After a delay at the gate, C3, at Ohare on Sunday, I left my Blk ski coat on the bench at the gate, lost! Please review my lob claim, thx.

Very bad! They kept delaying my flight and wouldn’t do anything about it

They brought an empty plane to the gate. Then a flight delay was announced for maintenance and waiting on a part. I was then put on a flight to San Francisco instead with a connecting flight to my final destination. Arrived at my final destination 2 hours late.

The only downside was my cell phone charger wouldn’t work in the charging port but everyone else’s would work in them all. My cell phone cable works fine in my hotel room in Frankfurt.

Flight and crew were great. United didn't inform crew of immigration process which was disappointing!

Flight team stood out for perzonal attention, kindness at bright cheery attitudes at 8am. Very helpful.

Seats had less pitch than a regional jet. Food was OK. Have to buy alcohol on US based carriers flying international. Boarding was a mess. Did not have bags but overhead space was gone quick. Would like to see the airlines enforce the one bag over and one bag under policy

Ot was overall fine. Left on time and had basic snacks. Weather was finicky but that’s not the airlines fault.

nice and clean plane but the seats and the comfort was not what i expected. i expected more based on all the ads and reviews that i've read. I guess you get what you pay for in economy.

Overall it was good. Food was bad. I ordered gluten free vegetarian meal. But I got gluten free chicken for my long flight from Seattle to Istanbul. I don’t eat any kind of meat. Second meal I got eggplant with meat which I couldn’t eat. I don’t understand why we can’t get gluten free vegetarian meal for a 12 hour flight. I eat the bread and that was it.

Worse worse worse, i would not recommend this airline to anyone. Istanbul airport maybe State of the Art facility but staff is rude, only works if they get tips, and they push you to give tips even though my family had spent $50 in tips. Airline staff doesn't speak english so you really can't understand them. It was a nightmare travelling with Turkish. Never again.

As a big guy the seats are way too small for me. Would prefer more comfortable seats on these long haul flights.

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

Ground staff and cabin crew were excellent. Flight was perfectly on time. Zero issues.

Even after a delay, getting off the ground, thanks for keeping me safe, the airline made certain that my connecting flight was rebooked to get me to my final destination. It was actually rebooked twice, and my luggage still managed to meet me. The airline gave me a credit for food and beverage to be used at the airport vendors, regretfully, the credit did not transfer to my final boarding pass. Oh, well…

Trip was smooth, good drew, average meal, almost cold coffee. Excellent landing. Did not enjoy going down the stairs, walking to the gate, walking up the stairs, going a long walk to the exchange gate, and going down the stairs again to be bussed all the way where we originally landed to take our next flight! Over all an average experience. Thank you.

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.

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

Information on your arrival and departure airports