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$294+ 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 11/14. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — OPO
Aug 18 — Aug 251
Mon 8/18
Mon 8/25
1 adult, Economy
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Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Porto are usually found in March or October, 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 August 13, 2025.

Round-trip from

$608
(Iberia)

One-way from

$294
(Kiwi.com)

Popular in

June

Cheapest in

March

Average price

$1,116
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. 16% potential increase in price ($200 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($27 potential savings vs. average RT price).
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Average for round-trip flights in August 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 August 13, 2025.

This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/1110:39 amSEA - OPO
2 stops17h 06mIberia
Wed 11/194:40 pmOPO - SEA
2 stops26h 04mIberia
Deal found 8/11$608
This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/210:35 amSEA - OPO
2 stops17h 10mIberia
Wed 12/1012:25 pmOPO - SEA
2 stops40h 50mIberia
Deal found 8/11$614
This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/110:35 amSEA - OPO
2 stops37h 05mIberia
Mon 12/812:25 pmOPO - SEA
2 stops29h 04mIberia
Deal found 8/11$616
This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/210:35 amSEA - OPO
2 stops17h 10mIberia
Tue 12/94:40 pmOPO - SEA
2 stops36h 35mIberia
Deal found 8/11$619
This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/1512:59 amSEA - OPO
2 stops31h 01mIberia
Tue 11/258:20 amOPO - SEA
2 stops40h 35mIberia
Deal found 8/11$621
This Ovago deal was found by Cheapflights users on 8/11. 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 Ovago is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/192:52 pmSEA - OPO
2 stops32h 43mBritish Airways
Mon 11/38:40 pmOPO - SEA
2 stops33h 35mBritish Airways
Deal found 8/11$622
This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/306:50 pmSEA - OPO
2 stops28h 50mIberia
Mon 12/812:25 pmOPO - SEA
2 stops29h 04mIberia
Deal found 8/11$627
This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/910:35 amSEA - OPO
2 stops25h 25mIberia
Tue 11/1812:25 pmOPO - SEA
2 stops36h 30mIberia
Deal found 8/11$628
This Delta deal was found by Cheapflights users on 8/11. 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 11/111:40 pmSEA - OPO
1 stop12h 50mDelta
Tue 11/1811:25 amOPO - SEA
1 stop33h 50mDelta
Deal found 8/11$634
This Delta deal was found by Cheapflights users on 8/11. 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 11/111:40 pmSEA - OPO
1 stop12h 50mDelta
Wed 11/1911:25 amOPO - SEA
1 stop32h 00mDelta
Deal found 8/11$635
This Iberia deal was found by Cheapflights users on 8/11. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/306:50 pmSEA - OPO
2 stops28h 50mIberia
Tue 12/94:40 pmOPO - SEA
2 stops36h 35mIberia
Deal found 8/11$638
This Delta deal was found by Cheapflights users on 8/11. 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.
Mon 11/109:55 pmSEA - OPO
2 stops28h 35mDelta
Tue 11/1811:25 amOPO - SEA
1 stop33h 50mDelta
Deal found 8/11$639

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 August 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

Sun 10/19

2:52 pm-7:35 am

2 stops32h 43m

Porto

Mon 11/3

8:40 pm-10:15 pm

2 stops33h 35m

$622

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 11/9

10:35 am-8:00 pm

2 stops25h 25m

Porto

Tue 11/18

12:25 pm-4:55 pm

2 stops36h 30m

$628

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 11/10

9:55 pm-10:30 am

2 stops28h 35m

Porto

Wed 11/19

11:25 am-11:25 am

1 stop32h 00m

$639

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 11/10

9:55 pm-10:30 am

2 stops28h 35m

Porto

Tue 11/18

11:25 am-1:15 pm

1 stop33h 50m

$639

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 11/10

9:55 pm-10:30 am

2 stops28h 35m

Porto

Thu 11/20

11:25 am-1:15 pm

1 stop33h 50m

$639

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 9/23

12:30 pm-10:05 am

1 stop37h 35m

Porto

Tue 10/14

10:50 am-5:15 pm

1 stop38h 25m

$644

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 11/9

3:00 pm-3:25 pm

1 stop16h 25m

Porto

Tue 11/18

11:25 am-1:15 pm

1 stop33h 50m

$660

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 10/19

1:55 pm-10:15 pm

1 stop24h 20m

Porto

Mon 11/3

11:25 am-11:25 am

1 stop32h 00m

$661

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Sun 11/9

3:00 pm-3:25 pm

1 stop16h 25m

Porto

Mon 11/17

11:25 am-11:25 am

1 stop32h 00m

$661

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 10/14

7:10 pm-10:05 am

1 stop30h 55m

Porto

Tue 10/21

4:50 pm-5:15 pm

1 stop32h 25m

$669

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/12

Showing 1-10 of 21 results
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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 August 8, 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 $1,029). 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 August 13, 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.

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 August 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
8.0
Very good
7,979 reviews

Entertainment

7.9

Crew

8.5

Food

7.3

Comfort

7.9

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Delta
8.0
Very good
7,979 reviews
Delta
8.0
Very good
7,979 reviews

Entertainment

7.9

Crew

8.5

Food

7.3

Comfort

7.9

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
KLM
7.8
Good
1,381 reviews
Delta
8.0
Very good
7,979 reviews

Entertainment

7.9

Crew

8.5

Food

7.3

Comfort

7.9

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
United Airlines
7.4
Good
8,920 reviews
Delta
8.0
Very good
7,979 reviews

Entertainment

7.9

Crew

8.5

Food

7.3

Comfort

7.9

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Turkish Airlines
7.3
Good
3,942 reviews
Delta
8.0
Very good
7,979 reviews

Entertainment

7.9

Crew

8.5

Food

7.3

Comfort

7.9

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Lufthansa
6.8
Okay
7,317 reviews
Delta
8.0
Very good
7,979 reviews

Entertainment

7.9

Crew

8.5

Food

7.3

Comfort

7.9

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

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

    Our cheapest airline available from Seattle to Porto is Iberia. Our recent data shows that you can find tickets from as low as $608 on this airline. Users have found that Iberia is 41% 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, 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 $1,029). 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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

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 August 13, 2025.
AirlineCheapestAverageFlexibilityOn-time
LufthansaCheapest$642Average$963FlexibilityNo cancel feeOn-time76%
KLMCheapest$649Average$1,034FlexibilityNo cancel feeOn-time75%
DeltaCheapest$659Average$1,063FlexibilityNo cancel feeOn-timeN/A
British AirwaysCheapest$673Average$914FlexibilityNo cancel feeOn-time70%
Turkish AirlinesCheapest$685Average$833FlexibilityNo cancel feeOn-time77%
United AirlinesCheapest$717Average$1,203FlexibilityNo cancel feeOn-time69%

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