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$257+ Cheap flights from Seattle (SEA) to Porto (OPO)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 8/4. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — OPO
Mar 15 — Mar 221
Sun 3/15
Sun 3/22
1 adult, Economy
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Cheap flight deals from Seattle to Porto

Cheapest flights from Seattle to Porto
Explore the most affordable flight options available from Seattle to Porto. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 13, 2026.

This Air France deal was found by Cheapflights users on 2/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/136:40 pm
SEA
-
OPO
1 stop19h 20m
Multiple Airlines
Wed 4/224:20 pm
OPO
-
SEA
1 stop27h 25m
Multiple Airlines
Deal found 2/10$479
This Delta deal was found by Cheapflights users on 2/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/126:00 am
SEA
-
OPO
2 stops28h 10m
Delta
Thu 4/235:00 am
OPO
-
SEA
1 stop14h 45m
Delta
Deal found 2/10$488
This Delta deal was found by Cheapflights users on 2/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/136:40 pm
SEA
-
OPO
1 stop19h 20m
Delta
Wed 4/225:00 am
OPO
-
SEA
2 stops20h 16m
Delta
Deal found 2/10$489
This Delta deal was found by Cheapflights users on 2/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/126:00 am
SEA
-
OPO
2 stops28h 10m
Delta
Fri 4/245:00 am
OPO
-
SEA
2 stops23h 43m
Delta
Deal found 2/10$499
This American Airlines deal was found by Cheapflights users on 2/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/136:00 am
SEA
-
OPO
2 stops17h 40m
American Airlines
Thu 4/238:20 am
OPO
-
SEA
2 stops22h 18m
American Airlines
Deal found 2/13$501
This British Airways deal was found by Cheapflights users on 2/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure British Airways is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/138:20 pm
SEA
-
OPO
1 stop15h 30m
British Airways
Thu 4/238:20 am
OPO
-
SEA
2 stops22h 18m
British Airways
Deal found 2/13$503
This Delta deal was found by Cheapflights users on 2/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/126:00 am
SEA
-
OPO
2 stops28h 10m
Delta
Wed 4/224:25 pm
OPO
-
SEA
1 stop26h 50m
Delta
Deal found 2/10$508
This United Airlines deal was found by Cheapflights users on 2/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 3/118:00 am
SEA
-
OPO
2 stops24h 25m
United Airlines
Wed 3/186:00 am
OPO
-
SEA
2 stops25h 59m
United Airlines
Deal found 2/11$512
This Delta deal was found by Cheapflights users on 2/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/131:30 pm
SEA
-
OPO
1 stop17h 55m
Delta
Tue 10/205:00 am
OPO
-
SEA
1 stop19h 39m
Delta
Deal found 2/13$541
This United Airlines deal was found by Cheapflights users on 2/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/1211:03 pm
SEA
-
OPO
2 stops23h 57m
United Airlines
Tue 10/2012:15 pm
OPO
-
SEA
2 stops31h 25m
United Airlines
Deal found 2/13$542

Find flight deals from Seattle to Porto

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Porto (OPO). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated February 13, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$479
(Air France)

One-way from

$257
(FlightHub)

Popular in

December

Cheapest in

January

Average price

$753
Provider with most accurate pricing for Seattle/Tacoma Intl-Porto flight deals.
Search Deals
Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Porto flights.
Search Deals
From Seattle/Tacoma Intl to Porto
Search Deals
One-way flight from Seattle/Tacoma Intl to Porto
Search Deals
Highest demand for flights based on searches. 4% potential increase in price ($38 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($50 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to Porto that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated February 13, 2026.
Use the filters below to find and compare flights from Seattle to Porto that are best for you.

Fly from

Seattle

Fly to

Porto

Route

Depart

Return

Price

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 4/12

6:00 am-6:10 pm

2 stops28h 10m

Porto

Thu 4/23

5:00 am-11:45 am

1 stop14h 45m

$488

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 4/13

6:40 pm-10:00 pm

1 stop19h 20m

Porto

Wed 4/22

5:00 am-5:16 pm

2 stops20h 16m

$489

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 4/12

6:00 am-6:10 pm

2 stops28h 10m

Porto

Fri 4/24

5:00 am-8:43 pm

2 stops23h 43m

$499

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 4/12

6:00 am-6:10 pm

2 stops28h 10m

Porto

Tue 4/21

5:00 am-11:45 am

1 stop14h 45m

$541

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 4/12

8:20 pm-8:20 pm

1 stop16h 00m

Porto

Mon 4/20

9:10 pm-11:35 am

1 stop22h 25m

$590

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 4/12

1:35 pm-8:20 pm

1 stop22h 45m

Porto

Wed 4/22

8:20 pm-11:35 am

1 stop23h 15m

$590

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Fri 4/10

7:15 am-3:30 pm

2 stops24h 15m

Porto

Thu 4/23

5:00 am-4:30 pm

1 stop19h 30m

$663

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Fri 4/10

7:15 am-3:30 pm

2 stops24h 15m

Porto

Fri 4/24

5:00 am-8:43 pm

2 stops23h 43m

$674

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 4/12

6:00 am-6:10 pm

2 stops28h 10m

Porto

Sun 4/26

5:00 am-5:50 pm

2 stops20h 50m

$674

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 8/4

7:20 pm-7:00 am

2 stops27h 40m

$257

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/10

Showing 1-10 of 19 results
1
2

Compare providers for flights from Seattle to Porto

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to Porto in February.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
AranGrantPrice Accuracy2 starsTrust Score*2 stars
OvagoPrice Accuracy2 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Seattle-Porto flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Seattle-Porto flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Seattle-Porto flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Seattle-Porto flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-Porto flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Seattle to Porto

Have a flexible travel schedule? Discover the best time to fly to Porto from Seattle with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

How far ahead should I book a flight from Seattle to Porto?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to Porto. Price data was last updated on February 6, 2026.

Booking 45 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to Porto. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

What is the cheapest month to book a flight from Seattle to Porto?

Currently, January is the cheapest month in which you can book a flight from Seattle to Porto (average of $478). Flying from Seattle to Porto in June is currently the most expensive (average of $749). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Reviews of airlines servicing Porto

Get insights into the airlines that provide service to Porto. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Porto. Reviews last updated February 13, 2026.
Peruse reviews from past customers who have flown with Delta, KLM, and United Airlines from Seattle to Porto to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
8,192 reviews

Crew

8.5

Entertainment

7.8

Comfort

7.9

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
Delta
7.9
Good
8,192 reviews
Delta
7.9
Good
8,192 reviews

Crew

8.5

Entertainment

7.8

Comfort

7.9

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
KLM
7.7
Good
1,452 reviews
Delta
7.9
Good
8,192 reviews

Crew

8.5

Entertainment

7.8

Comfort

7.9

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
United Airlines
7.4
Good
9,285 reviews
Delta
7.9
Good
8,192 reviews

Crew

8.5

Entertainment

7.8

Comfort

7.9

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
Lufthansa
6.8
Okay
7,782 reviews
Delta
7.9
Good
8,192 reviews

Crew

8.5

Entertainment

7.8

Comfort

7.9

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.

Related info for your journey

Find useful and relevant information for your journey from Seattle to Porto. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Seattle to Porto?

    A quick flight from Seattle to Porto can take about 28h 10m. Delta provides one of the quickest options available for as low as $488. Airlines will cover a distance of 5083 mi.

  • What are the cheapest airlines flying from Seattle to Porto round-trip?

    Our cheapest airline available from Seattle to Porto is KLM. Our recent data shows that you can find tickets from as low as $490 on this airline. Additional options worth looking into are Lufthansa and Delta, starting at $503 and $580 round-trip. Users have found that KLM is 45% cheaper than the other options available to this destination.

  • What are the cheapest airlines to fly from Seattle to Porto one-way?

    $257 is the cheapest one-way deal found within the past few days, from United Airlines. You may also be able to find cheap deals on KLM and Delta, with prices starting from $378 and $434, respectively.

  • Can I find deals for flights from Seattle to Porto that include hotel bookings?

    Yes. In addition to deals on Seattle to Porto flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to Porto?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Porto.

  • Can I find deals for business class flights from Seattle to Porto?

    Yes. Cheapflights offers flight deals from Seattle to Porto by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to Porto?

    Currently, January is the cheapest month in which you can book a flight from Seattle to Porto (average of $478). Flying from Seattle to Porto in June is currently the most expensive (average of $749). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near Porto?

Book flights to Porto if you plan to visit one of these locations
Vila Nova de Gaia
Aveiro
Arcos de Valdevez
Coimbra

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Top 4 airlines flying from Seattle to Porto

Discover the top 4 airlines that operate flights from Seattle to Porto. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated February 13, 2026.
AirlineCheapestAverageFlexibilityOn-time
KLMCheapest$490Average$960FlexibilityNo cancel feeOn-time75%
LufthansaCheapest$503Average$877FlexibilityNo cancel feeOn-time76%
DeltaCheapest$580Average$845FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$664Average$953FlexibilityNo cancel feeOn-time69%

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