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$305+ 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 9/6. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — OPO
ago. 3 — ago. 101
dom. 8/3
dom. 8/10
1 adult, Economy
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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 julio 29, 2025.

Round-trip from

$625
(FlightHub)

One-way from

$305
(Kiwi.com)

Popular in

June

Cheapest in

January

Average price

$1,152
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 ($214 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($28 potential savings vs. average RT price).
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Average for round-trip flights in July 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 julio 29, 2025.

This United Airlines deal was found by Cheapflights users on 7/28. 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.
dom. 11/25:00 amSEA - OPO
1 stop19h 30mUnited Airlines
mar. 11/1812:35 pmOPO - SEA
1 stop18h 06mUnited Airlines
Deal found 7/28$583
This FlightHub deal was found by Cheapflights users on 7/28. 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.
mié. 11/263:10 pmSEA - OPO
1 stop14h 00mMultiple Airlines
mié. 1/2112:10 pmOPO - SEA
2 stops40h 49mMultiple Airlines
Deal found 7/28$614
This FlightHub deal was found by Cheapflights users on 7/28. 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.
mié. 11/263:10 pmSEA - OPO
1 stop14h 00mLufthansa
mié. 1/2112:30 pmOPO - SEA
1 stop31h 40mLufthansa
Deal found 7/28$618
This FlightHub deal was found by Cheapflights users on 7/29. 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.
mar. 8/197:10 pmSEA - OPO
1 stop36h 40mTurkish Airlines
mar. 9/2310:50 amOPO - SEA
1 stop38h 25mTurkish Airlines
Deal found 7/29$625
This FlightHub deal was found by Cheapflights users on 7/29. 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.
mié. 10/12:25 pmSEA - OPO
2 stops42h 40mScandinavian Airlines
mié. 10/2211:50 amOPO - SEA
2 stops54h 25mScandinavian Airlines
Deal found 7/29$742
This Expedia deal was found by Cheapflights users on 7/28. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 11/512:59 amSEA - OPO
2 stops22h 41mIberia
lun. 11/178:40 pmOPO - SEA
2 stops32h 38mIberia
Deal found 7/28$744
This Air Canada deal was found by Cheapflights users on 7/28. 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 Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 10/110:00 amSEA - OPO
2 stops24h 30mAir Canada
mié. 10/88:40 amOPO - SEA
2 stops17h 56mAir Canada
Deal found 7/28$763
This SWISS deal was found by Cheapflights users on 7/28. 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.
vie. 10/31:00 pmSEA - OPO
2 stops21h 30mSWISS
lun. 10/207:20 pmOPO - SEA
2 stops31h 16mSWISS
Deal found 7/28$828

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 julio 29, 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

mar. 8/19

7:10 pm-3:50 pm

1 stop36h 40m

Porto

mar. 9/23

10:50 am-5:15 pm

1 stop38h 25m

$625

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

dom. 10/19

11:40 pm-9:45 am

2 stops26h 05m

Porto

mié. 10/29

12:35 pm-11:43 am

2 stops30h 08m

$678

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

lun. 10/13

2:20 pm-3:45 pm

1 stop17h 25m

Porto

vie. 10/24

8:40 am-6:36 pm

2 stops17h 56m

$688

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

mié. 10/1

2:25 pm-5:05 pm

2 stops42h 40m

Porto

mié. 10/22

11:50 am-10:15 am

2 stops54h 25m

$742

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

mié. 10/1

10:00 am-6:30 pm

2 stops24h 30m

Porto

mié. 10/8

8:40 am-6:36 pm

2 stops17h 56m

$763

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

mié. 10/1

6:50 pm-11:20 pm

1 stop20h 30m

Porto

mié. 10/22

6:00 am-6:49 pm

2 stops20h 49m

$768

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

vie. 10/3

1:00 pm-6:30 pm

2 stops21h 30m

Porto

lun. 10/20

7:20 pm-6:36 pm

2 stops31h 16m

$828

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

sáb. 9/6

9:39 pm-9:15 am

2 stops51h 36m

$305

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

lun. 11/17

2:00 pm-2:55 pm

1 stop16h 55m

$490

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

jue. 1/15

1:40 pm-10:30 am

1 stop12h 50m

$533

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/28

Showing 1-10 of 15 results
1
2

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 July 25, 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 $1,033). 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 julio 29, 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 julio 29, 2025.
Peruse reviews from past customers who have flown with KLM, Air France, and SWISS 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.
KLM
7.8
Good
1,383 reviews

Boarding

7.8

Overall

7.8

Entertainment

7.1

Comfort

7.7

Crew

8.4

Food

7.3

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2025

AMS - BOS

A two and half hour delay caused havoc with all connections. Otherwise on board service was great.
KLM
7.8
Good
1,383 reviews
KLM
7.8
Good
1,383 reviews

Boarding

7.8

Overall

7.8

Entertainment

7.1

Comfort

7.7

Crew

8.4

Food

7.3

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2025

AMS - BOS

A two and half hour delay caused havoc with all connections. Otherwise on board service was great.
Air France
7.5
Good
1,465 reviews
KLM
7.8
Good
1,383 reviews

Boarding

7.8

Overall

7.8

Entertainment

7.1

Comfort

7.7

Crew

8.4

Food

7.3

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2025

AMS - BOS

A two and half hour delay caused havoc with all connections. Otherwise on board service was great.
SWISS
7.5
Good
1,683 reviews
KLM
7.8
Good
1,383 reviews

Boarding

7.8

Overall

7.8

Entertainment

7.1

Comfort

7.7

Crew

8.4

Food

7.3

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2025

AMS - BOS

A two and half hour delay caused havoc with all connections. Otherwise on board service was great.
United Airlines
7.4
Good
8,899 reviews
KLM
7.8
Good
1,383 reviews

Boarding

7.8

Overall

7.8

Entertainment

7.1

Comfort

7.7

Crew

8.4

Food

7.3

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2025

AMS - BOS

A two and half hour delay caused havoc with all connections. Otherwise on board service was great.
Turkish Airlines
7.3
Good
3,925 reviews
KLM
7.8
Good
1,383 reviews

Boarding

7.8

Overall

7.8

Entertainment

7.1

Comfort

7.7

Crew

8.4

Food

7.3

Reviews

1 / 20
4.0
Okay

Anonymous,Jun 2025

AMS - BOS

A two and half hour delay caused havoc with all connections. Otherwise on board service was great.

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 Turkish Airlines. Our recent data shows that you can find tickets from as low as $625 on this airline. Additional options worth looking into are United Airlines and Scandinavian Airlines, starting at $678 and $742 round-trip. Users have found that Turkish Airlines is 38% cheaper than the other options available to this destination.

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

    $490 is the cheapest one-way deal found within the past few days, from Lufthansa. You may also be able to find cheap deals on KLM and United Airlines, with prices starting from $533 and $578, 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 $1,033). 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
Coimbra
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 julio 29, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$636Average$1,037FlexibilityNo cancel feeOn-timeN/A
LufthansaCheapest$642Average$963FlexibilityNo cancel feeOn-time76%
KLMCheapest$648Average$1,000FlexibilityNo cancel feeOn-time75%
British AirwaysCheapest$673Average$1,134FlexibilityNo cancel feeOn-time70%
Turkish AirlinesCheapest$685Average$841FlexibilityNo cancel feeOn-time77%
United AirlinesCheapest$707Average$1,201FlexibilityNo cancel feeOn-time69%

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