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$373+ Cheap flights from Porto (OPO) to Seattle (SEA)

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 12/15. Fares are subject to change and may not be available on all flights or dates of travel.
OPO — SEA
Oct 15 — Oct 221
Wed 10/15
Wed 10/22
1 adult, Economy
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Cheap flight deals from Porto to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Porto (OPO) to Seattle (SEA). 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 September 15, 2025.

Round-trip from

$775
(Delta)

One-way from

$373
(Kiwi.com)

Popular in

August

Cheapest in

October

Average price

$817
From Porto to Seattle/Tacoma Intl
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One-way flight from Porto to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 11% potential increase in price ($119 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($24 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Porto to Seattle

Cheapest flights from Porto to Seattle
Explore the most affordable flight options available from Porto to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 15, 2025.

This Delta deal was found by Cheapflights users on 9/14. 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.
Fri 9/266:40 amOPO - SEA
1 stop17h 25mDelta
Tue 9/301:30 pmSEA - OPO
1 stop18h 00mDelta
Deal found 9/14$775
This Delta deal was found by Cheapflights users on 9/13. 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.
Fri 10/316:30 amOPO - SEA
2 stops20h 49mDelta
Mon 11/107:30 amSEA - OPO
2 stops18h 45mDelta
Deal found 9/13$780
This KLM deal was found by Cheapflights users on 9/14. 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.
Wed 10/2911:15 amOPO - SEA
1 stop32h 30mKLM
Wed 11/59:29 amSEA - OPO
2 stops17h 01mKLM
Deal found 9/14$784
This KLM deal was found by Cheapflights users on 9/13. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/316:30 amOPO - SEA
2 stops20h 49mKLM
Mon 11/102:05 pmSEA - OPO
1 stop36h 25mKLM
Deal found 9/13$785
This Delta deal was found by Cheapflights users on 9/13. 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.
Sat 11/16:00 amOPO - SEA
2 stops23h 27mDelta
Mon 11/107:30 amSEA - OPO
2 stops18h 45mDelta
Deal found 9/13$790
This KLM deal was found by Cheapflights users on 9/15. 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.
Mon 10/134:20 pmOPO - SEA
1 stop33h 20mKLM
Mon 10/201:30 pmSEA - OPO
1 stop18h 00mKLM
Deal found 9/15$792
This Mytrip deal was found by Cheapflights users on 9/13. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/3112:00 pmOPO - SEA
3 stops35h 40mMultiple Airlines
Mon 11/105:40 pmSEA - OPO
3 stops30h 30mMultiple Airlines
Deal found 9/13$795
This Lufthansa deal was found by Cheapflights users on 9/15. 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 Lufthansa is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/136:00 amOPO - SEA
1 stop13h 55mLufthansa
Mon 10/207:00 amSEA - OPO
2 stops19h 20mLufthansa
Deal found 9/15$832

Cheapflights Fare Finder

 
Customize your flight search to find flights from Porto to Seattle 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 September 15, 2025.
Use the filters below to find and compare flights from Porto to Seattle that are best for you.

Fly from

Porto

Fly to

Seattle

Route

Depart

Return

Price

PortoSeattle

OPO - SEA

OPOSEA

Porto

Wed 10/29

4:10 pm-12:45 pm

1 stop27h 35m

Seattle/Tacoma Intl

Wed 11/5

2:05 pm-10:25 am

1 stop36h 20m

$775

PortoSeattle

OPO - SEA

OPOSEA

Porto

Fri 9/26

6:40 am-4:05 pm

1 stop17h 25m

Seattle/Tacoma Intl

Tue 9/30

1:30 pm-3:30 pm

1 stop18h 00m

$775

PortoSeattle

OPO - SEA

OPOSEA

Porto

Tue 11/18

4:10 pm-11:45 am

1 stop27h 35m

Seattle/Tacoma Intl

Mon 12/1

2:05 pm-10:30 am

1 stop36h 25m

$775

PortoSeattle

OPO - SEA

OPOSEA

Porto

Tue 11/18

8:40 pm-11:18 pm

2 stops34h 38m

Seattle/Tacoma Intl

Mon 12/1

7:19 am-11:45 am

2 stops20h 26m

$780

PortoSeattle

OPO - SEA

OPOSEA

Porto

Fri 10/31

6:30 am-8:19 pm

2 stops20h 49m

Seattle/Tacoma Intl

Mon 11/10

7:30 am-10:15 am

2 stops18h 45m

$780

PortoSeattle

OPO - SEA

OPOSEA

Porto

Wed 10/29

6:00 am-8:45 pm

2 stops21h 45m

Seattle/Tacoma Intl

Wed 11/5

6:00 am-10:30 am

2 stops20h 30m

$781

PortoSeattle

OPO - SEA

OPOSEA

Porto

Fri 10/31

6:30 am-8:19 pm

2 stops20h 49m

Seattle/Tacoma Intl

Mon 11/10

2:05 pm-10:30 am

1 stop36h 25m

$785

PortoSeattle

OPO - SEA

OPOSEA

Porto

Mon 12/15

6:15 am-2:20 pm

2 stops40h 05m

$373

PortoSeattle

OPO - SEA

OPOSEA

Porto

Fri 12/12

6:15 am-10:23 am

3 stops36h 08m

$393

PortoSeattle

OPO - SEA

OPOSEA

Porto

Sun 12/14

5:00 pm-2:20 pm

3 stops53h 20m

$400

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/13

Showing 1-10 of 14 results
1
2

Best time to book a flight from Porto to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Porto 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 Porto to Seattle

How much does it cost to fly round-trip from Porto to Seattle?

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated September 15, 2025.
Peruse reviews from past customers who have flown with KLM from Porto to Seattle 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.
KLM
7.8
Good
1,385 reviews

Crew

8.4

Entertainment

7.2

Overall

7.8

Boarding

7.8

Comfort

7.7

Food

7.3

Reviews

1 / 20
4.0
Okay

Mark,Sep 2025

AMS - BHX

Crew and snacks were good, boarding wasn't great as busses were used rather than boarding tunnels. Also endured a one hour delay.
KLM
7.8
Good
1,385 reviews
KLM
7.8
Good
1,385 reviews

Crew

8.4

Entertainment

7.2

Overall

7.8

Boarding

7.8

Comfort

7.7

Food

7.3

Reviews

1 / 20
4.0
Okay

Mark,Sep 2025

AMS - BHX

Crew and snacks were good, boarding wasn't great as busses were used rather than boarding tunnels. Also endured a one hour delay.

Related info for your journey

Find useful and relevant information for your journey from Porto to Seattle. 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 Porto to Seattle?

    There are many flights that can get you from Porto to Seattle in 17h 25m. Fly via KLM or Delta to get the fastest option. Porto and Seattle are separated by a distance of 5083 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • What is the cheapest airline to fly from Porto to Seattle round-trip?

    Currently priced at $794, KLM will fly you from Porto to Seattle and back. In addition to KLM, many other airlines offer competitively priced options for your trip. Users have found that KLM is 9% cheaper than the other options available to this destination.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Porto to Seattle 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 Porto to Seattle?

    Currently, January is the cheapest month in which you can book a flight from Porto to Seattle (average of $238). Flying from Porto to Seattle in June is currently the most expensive (average of $387). 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
SeaTac
Tukwila
Tacoma
Lakewood
Ocean Shores
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Leavenworth
Renton
Lacey
Olympia
Kent
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Cle Elum
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Shoreline

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Porto to Seattle

See prices for flight routes from nearby airports that may be better suited for you.
Lisbon to Seattle flights
Lisbon to Portland flights

Top airline flying from Porto to Seattle

Discover the top airline that operate flights from Porto to Seattle. 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 September 15, 2025.
AirlineCheapestAverageFlexibilityOn-time
KLMCheapest$794Average$870FlexibilityNo cancel feeOn-time75%

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