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Cheap flights from Seattle to Porto from $281

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Seattle to Porto departing on 10/18. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Find the cheapest flights from Seattle to Porto

Cheap round-trip flights

Multiple Airlines Logo
2:55 pm - 10:05 pmSEA-OPO
23h 10m3 stops
Multiple Airlines Logo
7:15 am - 9:45 pmOPO-SEA
22h 30m2 stops
$576Multiple Airlines
Find Deal
Wed, Oct 15 - Wed, Oct 22
Multiple Airlines Logo
7:30 am - 10:00 amSEA-OPO
18h 30m2 stops
Multiple Airlines Logo
7:15 am - 9:45 pmOPO-SEA
22h 30m2 stops
$578Multiple Airlines
Find Deal
Wed, Oct 15 - Wed, Oct 22
Multiple Airlines Logo
5:30 am - 6:30 pmSEA-OPO
29h 00m2 stops
Multiple Airlines Logo
6:00 am - 11:55 amOPO-SEA
13h 55m1 stop
$610Multiple Airlines
Find Deal
Wed, Oct 15 - Wed, Oct 22
Lufthansa Logo
2:20 pm - 3:45 pmSEA-OPO
17h 25m1 stop
Lufthansa Logo
6:15 am - 2:20 pmOPO-SEA
15h 05m1 stop
$619Lufthansa
Find Deal
Tue, Oct 14 - Fri, Oct 31
KLM Logo
1:30 pm - 3:30 pmSEA-OPO
18h 00m1 stop
KLM Logo
11:25 am - 11:25 amOPO-SEA
32h 00m1 stop
$640KLM
Find Deal
Tue, Oct 7 - Mon, Nov 3
Lufthansa Logo
3:00 pm - 2:45 pmSEA-OPO
16h 45m1 stop
Lufthansa Logo
6:15 am - 1:20 pmOPO-SEA
15h 05m1 stop
$644Lufthansa
Find Deal
Fri, Oct 31 - Fri, Nov 7
Delta Logo
10:15 am - 3:30 pmSEA-OPO
21h 15m2 stops
Delta Logo
6:15 am - 10:06 pmOPO-SEA
23h 51m2 stops
$657Delta
Find Deal
Wed, Sep 24 - Wed, Oct 1
KLM Logo
5:40 pm - 7:15 pmSEA-OPO
17h 35m1 stop
KLM Logo
11:25 am - 11:25 amOPO-SEA
32h 00m1 stop
$671KLM
Find Deal
Tue, Oct 7 - Mon, Nov 3
Delta Logo
12:45 pm - 3:30 pmSEA-OPO
18h 45m2 stops
Delta Logo
6:40 am - 10:06 pmOPO-SEA
23h 26m2 stops
$706Delta
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Mon, Sep 22 - Fri, Oct 3
United Airlines Logo
8:00 am - 11:40 amSEA-OPO
20h 40m2 stops
United Airlines Logo
6:00 am - 10:45 pmOPO-SEA
24h 45m2 stops
$742United Airlines
Find Deal
Fri, Oct 31 - Fri, Nov 7

SWISS flights from Seattle to Porto

Our best SWISS deals on Seattle to Porto flight tickets
SWISS
Oct 8
SEA1:00 pmSeattle/Tacoma Intl
21h 30m
2 stops
OPO6:30 pmPorto
Oct 29
OPO7:20 pmPorto
34h 55m
2 stops
SEA11:15 pmSeattle/Tacoma Intl
$682
Find similar
SWISS
Oct 1
SEA3:28 pmSeattle/Tacoma Intl
19h 02m
2 stops
OPO6:30 pmPorto
Oct 22
OPO8:40 amPorto
22h 35m
2 stops
SEA11:15 pmSeattle/Tacoma Intl
$738
Find similar

KLM flights from Seattle to Porto

Our best KLM deals on Seattle to Porto flight tickets
KLM
Oct 7
SEA1:30 pmSeattle/Tacoma Intl
18h 00m
1 stop
OPO3:30 pmPorto
Nov 3
OPO11:25 amPorto
32h 00m
1 stop
SEA11:25 amSeattle/Tacoma Intl
$640
Find similar
KLM
Oct 7
SEA5:40 pmSeattle/Tacoma Intl
17h 35m
1 stop
OPO7:15 pmPorto
Nov 3
OPO11:25 amPorto
32h 00m
1 stop
SEA11:25 amSeattle/Tacoma Intl
$671
Find similar
KLM
Oct 8
SEA1:30 pmSeattle/Tacoma Intl
18h 00m
1 stop
OPO3:30 pmPorto
Oct 29
OPO11:25 amPorto
32h 00m
1 stop
SEA12:25 pmSeattle/Tacoma Intl
$685
Find similar

momondo 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, momondo users made 832,500 searches. Data last updated September 17, 2025.
Use the filters below to find and compare flights from Seattle to Porto that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 10/15

2:55 pm-10:05 pm

3 stops23h 10m

Porto

Wed 10/22

7:15 am-9:45 pm

2 stops22h 30m

$576

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 10/15

7:30 am-10:00 am

2 stops18h 30m

Porto

Wed 10/22

7:15 am-9:45 pm

2 stops22h 30m

$578

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 10/15

5:30 am-6:30 pm

2 stops29h 00m

Porto

Wed 10/22

6:00 am-11:55 am

1 stop13h 55m

$610

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 10/14

2:20 pm-3:45 pm

1 stop17h 25m

Porto

Fri 10/31

6:15 am-2:20 pm

1 stop15h 05m

$619

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 10/7

1:30 pm-3:30 pm

1 stop18h 00m

Porto

Mon 11/3

11:25 am-11:25 am

1 stop32h 00m

$640

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Fri 10/31

3:00 pm-2:45 pm

1 stop16h 45m

Porto

Fri 11/7

6:15 am-1:20 pm

1 stop15h 05m

$644

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Wed 9/24

10:15 am-3:30 pm

2 stops21h 15m

Porto

Wed 10/1

6:15 am-10:06 pm

2 stops23h 51m

$657

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Tue 10/7

5:40 pm-7:15 pm

1 stop17h 35m

Porto

Mon 11/3

11:25 am-11:25 am

1 stop32h 00m

$671

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Mon 9/22

12:45 pm-3:30 pm

2 stops18h 45m

Porto

Fri 10/3

6:40 am-10:06 pm

2 stops23h 26m

$706

SeattlePorto

SEA - OPO

SEAOPO

Seattle/Tacoma Intl

Fri 10/31

8:00 am-11:40 am

2 stops20h 40m

Porto

Fri 11/7

6:00 am-10:45 pm

2 stops24h 45m

$742

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Porto from

How to get the cheapest flight ticket from Seattle to Porto

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to Porto?

The month of March is, on average, the cheapest month to fly to Porto from Seattle, with most prices found around $788. If you aren’t able to travel during the month of March, then book flights to Porto from Seattle during October instead. Flights to Porto in October, while not as cheap as those in March, still average around $795.

What is the cheapest day to depart on your flight to Porto?

The cheapest day to depart on your flight to Porto is on a Tuesday when prices can be found for as low as $1,008. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Thursday because tickets tend to average around $1,286. These prices are subject to change though, so be sure to set up a Price Alert for flights to Porto.

What is the cheapest time of day to depart on your flight to Porto?

In the evening is the cheapest time of day to fly from Seattle to Porto when you can find flight prices for as low as $837. Flying to Porto in the evening is an ideal time because this is during off-peak travel hours. If you have a flexible travel schedule, then try to avoid flying in the morning when prices are $1,130 on average. Flights to Porto from Seattle in the morning are generally more expensive because this time of day is more convenient for travelers’ schedules.

How far in advance should I book a flight to Porto?

You are more likely to see cheaper flights to Porto from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to Porto for around $1,034 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Porto from Seattle for as low as $805 on momondo.

Can stopping save me money on Seattle to Porto flights?

You could potentially save up to 5% on your flight if you consider stops on a Seattle to Porto flight.

How have Seattle to Porto flight prices changed over time?

As of September 2025, prices for Seattle to Porto flights are approximately 20% cheaper when compared to flights at the same time last year.

When to book flights from Seattle to Porto

Are you open to changing your travel dates? Check out the ideal times to fly from Seattle to Porto according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Seattle to Porto (SEA to OPO) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Seattle to Porto

Direct flights

None
There are no direct flights from Seattle to Porto. There are no popular flight routes from Seattle to Porto.
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  • How far is Seattle/Tacoma Intl to Porto by plane?

    Seattle/Tacoma Intl and Porto are 5083.1 mi apart from one another. Typically, this will take 16h 45m by plane in normal conditions.

  • When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to Porto Airport?

    Prices for flights from Seattle/Tacoma Intl Airport to Porto Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Seattle/Tacoma Intl Airport to Porto Airport?

  • How old do you have to be to fly from Seattle/Tacoma Intl Airport to Porto Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Seattle/Tacoma Intl Airport to Porto Airport.

  • What documentation or ID do you need to fly to Porto Airport?

    The travel and health documents you'll need for your trip to Porto Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Porto Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • What is the most popular airline from Seattle to Porto?

Best airlines flying from Seattle to Porto

Compare and see reviews for airlines that fly from Seattle to Porto with momondo
Airline
Rating
Free Cancellation
Price
DeltaPriceFrom $647Free CancellationRating
7.9
7,961 reviews
Search Delta flights
KLMPriceFrom $648Free CancellationRating
7.8
1,386 reviews
Search KLM flights
Turkish AirlinesPriceFrom $685Free CancellationRating
7.3
3,965 reviews
Search Turkish Airlines flights
LufthansaPriceFrom $696Free CancellationRating
6.8
7,409 reviews
Search Lufthansa flights
United AirlinesPriceFrom $707Free CancellationRating
7.4
8,926 reviews
Search United Airlines flights
British AirwaysPriceFrom $741Free CancellationRating
6.7
7,367 reviews
Search British Airways flights

Traveling to a place near Porto?

Book flights to Porto if you plan to visit one of these locations
Vila Nova de Gaia
Aveiro
Coimbra
Braga
Matosinhos
Caminha
Guimarães
Esposende
Lamego
Chaves
Espinho
Arcos de Valdevez
Viseu
Ponte de Lima
Pinhao
Santa Maria da Feira
Curia
Penafiel
Mesao Frio
Mira

Why use momondo?

Why should I use momondo to find a flight deal from Seattle to Porto?

To find the flight that best suits your needs, momondo gathers a range of flights from a large pool of different airlines and agents; you can then use our insights and filters to find and book the right flight to Porto from Seattle.

Can I find flights from Seattle to Porto with flexible booking policies on momondo?

Yes. All flights to Porto from Seattle on momondo can be compared and filtered by various policies on offer, including flexible booking.

How can momondo help me find flights from Seattle to Porto?

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from Seattle to Porto.

I’m not ready to book a flight from Seattle to Porto right now. Can momondo alert me if prices change?

If you are simply researching potential flights to Porto, momondo offers a useful price alert feature which will track prices for flights to Porto from Seattle and alert you when they change.

An easier way to manage your Porto trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
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