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$312+ 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 1/7. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — OPO
Dec 13 — Dec 201
Sat 12/13
Sat 12/20
1 adult, Economy
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1. Tell us where you want to go

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Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Porto are usually found in October or March, booked 31 days in advance, depart on a Tuesday or Monday and return on a Monday

Find 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 November 13, 2025.

This Gotogate deal was found by Cheapflights users on 11/11. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/33:10 pmSEA - OPO
1 stop24h 30mMultiple Airlines
Fri 12/126:30 amOPO - SEA
2 stops20h 46mMultiple Airlines
Deal found 11/11$658
This Cheapflightsfares deal was found by Cheapflights users on 11/11. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/33:10 pmSEA - OPO
1 stop14h 05mLufthansa
Fri 12/126:30 amOPO - SEA
1 stop14h 50mLufthansa
Deal found 11/11$660
This FlightHub deal was found by Cheapflights users on 11/11. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/32:05 pmSEA - OPO
2 stops42h 50mScandinavian Airlines
Fri 12/125:35 pmOPO - SEA
2 stops36h 39mScandinavian Airlines
Deal found 11/11$669
This KLM deal was found by Cheapflights users on 11/12. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/21:40 pmSEA - OPO
1 stop12h 50mKLM
Thu 12/1111:15 amOPO - SEA
1 stop32h 35mKLM
Deal found 11/12$677
This KLM deal was found by Cheapflights users on 11/10. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/302:05 pmSEA - OPO
1 stop36h 25mKLM
Sat 12/69:25 amOPO - SEA
1 stop34h 25mKLM
Deal found 11/10$678
This Delta deal was found by Cheapflights users on 11/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/2610:15 pmSEA - OPO
2 stops28h 10mDelta
Tue 12/2311:15 amOPO - SEA
1 stop32h 35mDelta
Deal found 11/11$681
This KLM deal was found by Cheapflights users on 11/10. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/43:05 pmSEA - OPO
1 stop16h 20mKLM
Thu 12/114:10 pmOPO - SEA
1 stop27h 40mKLM
Deal found 11/10$682
This Delta deal was found by Cheapflights users on 11/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/253:00 pmSEA - OPO
1 stop16h 25mDelta
Wed 12/2411:15 amOPO - SEA
1 stop32h 35mDelta
Deal found 11/11$683
This Delta deal was found by Cheapflights users on 11/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/257:10 amSEA - OPO
2 stops24h 15mDelta
Tue 12/2311:15 amOPO - SEA
1 stop32h 35mDelta
Deal found 11/11$687
This United Airlines deal was found by Cheapflights users on 11/11. 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 11/265:05 amSEA - OPO
2 stops20h 25mUnited Airlines
Wed 12/2412:30 pmOPO - SEA
2 stops20h 29mUnited Airlines
Deal found 11/11$688
This KAYAK deal was found by Cheapflights users on 11/11. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/263:10 pmSEA - OPO
1 stop24h 30mLufthansa
Mon 12/224:15 pmOPO - SEA
1 stop27h 55mLufthansa
Deal found 11/11$694

Cheap 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 November 13, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$477
(Delta)

One-way from

$372
(Kiwi.com)

Popular in

June

Cheapest in

October

Average price

$859
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. 18% potential increase in price ($223 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($29 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in November 2025
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 November 13, 2025.
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

Tue 1/13

1:40 pm-10:30 am

1 stop12h 50m

Porto

Thu 1/22

6:35 am-11:50 am

1 stop37h 15m

$477

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 1/13

1:40 pm-10:30 am

1 stop12h 50m

Porto

Mon 1/19

11:15 am-11:50 am

1 stop32h 35m

$477

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 1/14

2:10 pm-10:25 am

1 stop36h 15m

Porto

Thu 1/22

6:35 am-11:50 am

1 stop37h 15m

$478

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 1/14

2:10 pm-10:25 am

1 stop36h 15m

Porto

Wed 1/21

11:15 am-11:50 am

1 stop32h 35m

$478

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 1/14

2:10 pm-10:25 am

1 stop36h 15m

Porto

Tue 1/20

11:15 am-11:50 am

1 stop32h 35m

$478

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 1/14

2:10 pm-10:25 am

1 stop36h 15m

Porto

Mon 1/19

11:15 am-11:50 am

1 stop32h 35m

$478

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 1/12

2:10 pm-10:30 am

1 stop36h 20m

Porto

Thu 1/22

11:15 am-11:50 am

1 stop32h 35m

$479

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 1/12

2:10 pm-10:30 am

1 stop36h 20m

Porto

Mon 1/19

11:15 am-11:50 am

1 stop32h 35m

$479

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 1/12

2:10 pm-10:30 am

1 stop36h 20m

Porto

Wed 1/21

11:15 am-11:50 am

1 stop32h 35m

$479

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 1/14

9:59 pm-10:25 am

2 stops28h 26m

Porto

Sun 1/18

5:00 am-11:50 am

1 stop14h 50m

$481

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/13

Showing 1-10 of 17 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 November.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust Score*3 stars
AranGrantPrice 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 eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Seattle-Porto flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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 November 7, 2025.

Booking 31 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, October is the cheapest month in which you can book a flight from Seattle to Porto (average of $630). Flying from Seattle to Porto in June is currently the most expensive (average of $1,000). 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.

What is the cheapest time of day to fly from SEA to OPO?

Find hourly flight availability from Seattle to Porto. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated November 13, 2025.

It’s optimal to fly from Seattle to Porto in the evening. By choosing this option you can save up to 25% on the cost of your flight, compared to a flight in the morning.

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 November 13, 2025.
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
8,008 reviews

Comfort

7.9

Crew

8.5

Food

7.3

Boarding

8.1

Entertainment

7.9

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
8,008 reviews
Delta
7.9
Good
8,008 reviews

Comfort

7.9

Crew

8.5

Food

7.3

Boarding

8.1

Entertainment

7.9

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
1,411 reviews
Delta
7.9
Good
8,008 reviews

Comfort

7.9

Crew

8.5

Food

7.3

Boarding

8.1

Entertainment

7.9

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
9,017 reviews
Delta
7.9
Good
8,008 reviews

Comfort

7.9

Crew

8.5

Food

7.3

Boarding

8.1

Entertainment

7.9

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.
Turkish Airlines
7.3
Good
4,043 reviews
Delta
7.9
Good
8,008 reviews

Comfort

7.9

Crew

8.5

Food

7.3

Boarding

8.1

Entertainment

7.9

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
7,572 reviews
Delta
7.9
Good
8,008 reviews

Comfort

7.9

Crew

8.5

Food

7.3

Boarding

8.1

Entertainment

7.9

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 12h 50m. Delta provides one of the quickest options available for as low as $477. 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 Lufthansa. Our recent data shows that you can find tickets from as low as $642 on this airline. Additional options worth looking into are Delta and KLM, starting at $647 and $659 round-trip. Users have found that Lufthansa is 36% cheaper than the other options available to this destination.

  • 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, October is the cheapest month in which you can book a flight from Seattle to Porto (average of $630). Flying from Seattle to Porto in June is currently the most expensive (average of $1,000). 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
Aveiro
Arcos de Valdevez
Coimbra
Vila Nova de Gaia

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Top 5 airlines flying from Seattle to Porto

Discover the top 5 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 November 13, 2025.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest$642Average$934FlexibilityNo cancel feeOn-time76%
DeltaCheapest$647Average$1,008FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$659Average$1,026FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$679Average$1,195FlexibilityNo cancel feeOn-time69%
Turkish AirlinesCheapest$685Average$845FlexibilityNo cancel feeOn-time77%

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