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$383+ 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 5/28. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — OPO
Apr 22 — Apr 291
Tue 4/22
Tue 4/29
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 January or March, booked 89 days in advance, depart on a Tuesday or Monday and return on a Monday

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 April 17, 2025.

Most accurate provider

AranGrant
3 stars

Most trusted provider

AranGrant
3 stars

Round-trip from

$714
(KLM)

One-way from

$383
(Kiwi.com)

Popular in

June

Cheapest in

January

Average price

$1,003
Provider with most accurate pricing for Seattle/Tacoma Intl-Porto flight deals.
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Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Porto flights.
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From Seattle/Tacoma Intl to Porto
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One-way flight from Seattle/Tacoma Intl to Porto
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Highest demand for flights based on searches. 17% potential increase in price ($223 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($25 potential savings vs. average RT price).
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Average for round-trip flights in April 2025
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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 April 17, 2025.

This Mytrip deal was found by Cheapflights users on 4/17. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/63:45 pmSEA - OPO
2 stops20h 35mMultiple Airlines
Tue 5/1310:25 pmOPO - SEA
3 stops31h 48mMultiple Airlines
Deal found 4/17$738
This FlightHub deal was found by Cheapflights users on 4/17. 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.
Mon 12/82:00 pmSEA - OPO
1 stop17h 15mLufthansa
Mon 12/291:45 pmOPO - SEA
1 stop31h 35mLufthansa
Deal found 4/17$743
This United Airlines deal was found by Cheapflights users on 4/17. 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.
Tue 10/78:45 amSEA - OPO
2 stops17h 00mUnited Airlines
Sat 11/112:35 pmOPO - SEA
1 stop16h 15mUnited Airlines
Deal found 4/17$767
This Delta deal was found by Cheapflights users on 4/17. 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 10/81:30 pmSEA - OPO
1 stop18h 00mDelta
Sat 11/15:00 amOPO - SEA
2 stops22h 49mDelta
Deal found 4/17$789
This FlightHub deal was found by Cheapflights users on 4/17. 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.
Sat 8/304:00 pmSEA - OPO
1 stop35h 10mScandinavian Airlines
Fri 9/125:55 pmOPO - SEA
2 stops36h 53mScandinavian Airlines
Deal found 4/17$805
This FlightHub deal was found by Cheapflights users on 4/17. 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 10/17:10 pmSEA - OPO
1 stop36h 40mTurkish Airlines
Wed 10/224:50 pmOPO - SEA
1 stop25h 45mTurkish Airlines
Deal found 4/17$808
This KLM deal was found by Cheapflights users on 4/17. 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 10/71:30 pmSEA - OPO
1 stop18h 00mKLM
Wed 10/295:00 amOPO - SEA
1 stop14h 50mKLM
Deal found 4/17$814
This SWISS deal was found by Cheapflights users on 4/17. 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 SWISS is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/62:40 pmSEA - OPO
2 stops33h 05mSWISS
Tue 5/138:40 amOPO - SEA
2 stops17h 53mSWISS
Deal found 4/17$816
This Gotogate deal was found by Cheapflights users on 4/17. 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.
Sun 5/185:30 amSEA - OPO
2 stops28h 45mAir Canada
Tue 6/36:00 amOPO - SEA
2 stops35h 18mAir Canada
Deal found 4/17$943

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 April 17, 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 5/6

3:45 pm-8:20 pm

2 stops20h 35m

Porto

Tue 5/13

10:25 pm-10:13 pm

3 stops31h 48m

$738

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 5/13

2:15 pm-3:45 pm

1 stop17h 30m

Porto

Wed 5/21

6:00 am-10:45 am

2 stops36h 45m

$815

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 5/6

2:40 pm-7:45 am

2 stops33h 05m

Porto

Tue 5/13

8:40 am-6:33 pm

2 stops17h 53m

$816

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 5/6

10:25 am-3:30 pm

2 stops21h 05m

Porto

Tue 5/13

6:20 am-3:57 pm

1 stop17h 37m

$819

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 5/18

7:10 pm-3:50 pm

1 stop36h 40m

Porto

Tue 6/3

4:50 pm-5:15 pm

1 stop32h 25m

$858

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 4/23

10:59 pm-5:05 pm

2 stops34h 06m

Porto

Wed 5/7

12:15 pm-8:49 pm

2 stops40h 34m

$872

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Thu 5/15

6:07 pm-10:15 pm

1 stop20h 08m

Porto

Thu 5/22

11:25 am-3:57 pm

1 stop36h 32m

$880

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 5/18

5:30 am-6:15 pm

2 stops28h 45m

Porto

Tue 6/3

6:00 am-9:18 am

2 stops35h 18m

$943

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Thu 7/3

2:20 pm-10:45 pm

1 stop24h 25m

Porto

Fri 7/18

6:15 am-4:59 pm

1 stop18h 44m

$1,064

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 6/29

8:20 pm-8:20 pm

1 stop16h 00m

Porto

Mon 7/7

9:10 pm-11:10 am

1 stop22h 00m

$1,200

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/17

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 April.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*2 stars
AranGrantPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 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 AranGrant to be most consistent on Cheapflights vs. AranGrant Users can find the same prices on Seattle-Porto flight deals on Cheapflights vs. AranGrant >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 AranGrant the most. AranGrant 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 April 11, 2025.

Booking 89 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 $523). Flying from Seattle to Porto in June is currently the most expensive (average of $1,081). 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 April 17, 2025.

It’s optimal to fly from Seattle to Porto in the evening. By choosing this option you can save up to 26% on the cost of your flight, compared to a flight in the morning.

What is the cheapest day to fly from Seattle to Porto?

Use this chart to determine the cheapest time to fly round-trip from Seattle to Porto. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Seattle to Porto flight should consider departing on Tuesday evenings when fares are most often at their lowest. Sunday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Rainfall in Porto by month

Plan your trip to Porto by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Porto ranges from 0.7 - 7.7 inches per month. December is typically the wettest month, when rainfall can reach 7.7 in. July is typically the driest time to visit Porto when rainfall is around 0.7 in.

Temperature in Porto by month

Plan your trip to Porto by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Porto, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 68.0 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 48.2 F).

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 April 17, 2025.
Delta
8.0
Very good
7,916 reviews

Boarding

8.2

Comfort

7.9

Crew

8.5

Entertainment

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Delta
8.0
Very good
7,916 reviews
Delta
8.0
Very good
7,916 reviews

Boarding

8.2

Comfort

7.9

Crew

8.5

Entertainment

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
KLM
7.8
Good
1,327 reviews
Delta
8.0
Very good
7,916 reviews

Boarding

8.2

Comfort

7.9

Crew

8.5

Entertainment

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
SWISS
7.5
Good
1,580 reviews
Delta
8.0
Very good
7,916 reviews

Boarding

8.2

Comfort

7.9

Crew

8.5

Entertainment

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
United Airlines
7.4
Good
8,667 reviews
Delta
8.0
Very good
7,916 reviews

Boarding

8.2

Comfort

7.9

Crew

8.5

Entertainment

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Turkish Airlines
7.3
Good
3,769 reviews
Delta
8.0
Very good
7,916 reviews

Boarding

8.2

Comfort

7.9

Crew

8.5

Entertainment

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

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.

  • 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 $714 on this airline. Additional options worth looking into are Delta and Air Canada, starting at $719 and $775 round-trip. Users have found that KLM is 32% cheaper than the other options available to this destination.

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

    $618 is the cheapest one-way deal found within the past few days, from Scandinavian Airlines. You may also be able to find cheap deals on Air Canada and United Airlines, with prices starting from $663 and $674, 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 $523). Flying from Seattle to Porto in June is currently the most expensive (average of $1,081). 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 Seattle?

Book flights to Seattle if you plan to visit one of these locations
Aveiro
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Matosinhos
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Top 6 airlines flying from Seattle to Porto

Discover the top 6 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 April 17, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$636Average$1,117FlexibilityNo cancel feeOn-timeN/A
LufthansaCheapest$642Average$1,077FlexibilityNo cancel feeOn-time76%
British AirwaysCheapest$673Average$1,134FlexibilityNo cancel feeOn-time70%
KLMCheapest$708Average$1,086FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$717Average$1,243FlexibilityNo cancel feeOn-time69%
Turkish AirlinesCheapest$765Average$866FlexibilityNo cancel feeOn-time77%

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