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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from $116

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Washington, D.C. Dulles Intl Airport to Seattle departing on 9/4. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Find the cheapest flights from Washington, D.C. Dulles Intl Airport to Seattle

Cheap round-trip flights

Frontier Logo
1:55 pm - 12:30 amIAD-SEA
13h 35m2 stops
Frontier Logo
12:05 pm - 9:17 amSEA-IAD
18h 12m2 stops
$236Frontier
Find Deal
Sun, Sep 7 - Thu, Sep 11
Frontier Logo
6:10 am - 5:33 pmIAD-SEA
14h 23m2 stops
Frontier Logo
7:00 am - 11:55 pmSEA-IAD
13h 55m2 stops
$242Frontier
Find Deal
Fri, Sep 12 - Sat, Sep 13
Alaska Airlines Logo
6:09 pm - 8:56 pmIAD-SEA
5h 47mnonstop
Alaska Airlines Logo
4:20 pm - 12:23 amSEA-IAD
5h 03mnonstop
$252Alaska Airlines
Find Deal
Sat, Sep 20 - Sat, Sep 27
Hawaiian Airlines Logo
7:00 am - 9:40 amIAD-SEA
5h 40mnonstop
Hawaiian Airlines Logo
4:20 pm - 12:23 amSEA-IAD
5h 03mnonstop
$272Hawaiian Airlines
Find Deal
Thu, Sep 4 - Wed, Sep 10
Hawaiian Airlines Logo
7:00 am - 9:40 amIAD-SEA
5h 40mnonstop
Hawaiian Airlines Logo
11:30 pm - 7:33 amSEA-IAD
5h 03mnonstop
$273Hawaiian Airlines
Find Deal
Thu, Sep 4 - Wed, Sep 10
Delta Logo
7:35 am - 10:20 amIAD-SEA
5h 45mnonstop
Delta Logo
9:55 pm - 5:55 amSEA-IAD
5h 00mnonstop
$277Delta
Find Deal
Thu, Sep 4 - Wed, Sep 10
Delta Logo
7:35 am - 10:20 amIAD-SEA
5h 45mnonstop
Delta Logo
9:55 pm - 5:55 amSEA-IAD
5h 00mnonstop
$278Delta
Find Deal
Thu, Sep 4 - Wed, Sep 10
United Airlines Logo
5:55 pm - 8:42 pmIAD-SEA
5h 47mnonstop
United Airlines Logo
7:34 pm - 7:00 amSEA-IAD
8h 26m1 stop
$287United Airlines
Find Deal
Sat, Sep 13 - Tue, Sep 16
United Airlines Logo
5:55 pm - 8:42 pmIAD-SEA
5h 47mnonstop
United Airlines Logo
10:55 pm - 6:58 amSEA-IAD
5h 03mnonstop
$295United Airlines
Find Deal
Fri, Sep 5 - Sun, Sep 7
Alaska Airlines Logo
5:52 pm - 10:20 amIAD-SEA
19h 28m1 stop
Alaska Airlines Logo
8:59 pm - 4:52 pmSEA-IAD
16h 53m1 stop
$296Alaska Airlines
Find Deal
Tue, Sep 9 - Tue, Sep 23

Alaska Airlines flights from Washington, D.C. Dulles Intl Airport to Seattle

Our best Alaska Airlines deals on Washington, D.C. Dulles Intl Airport to Seattle flight tickets
Alaska Airlines
Sep 20
IAD6:09 pmWashington, D.C. Dulles Intl
5h 47m
SEA8:56 pmSeattle/Tacoma Intl
Sep 27
SEA4:20 pmSeattle/Tacoma Intl
5h 03m
IAD12:23 amWashington, D.C. Dulles Intl
$252
Find similar
Alaska Airlines
Sep 9
IAD5:52 pmWashington, D.C. Dulles Intl
19h 28m
1 stop
SEA10:20 amSeattle/Tacoma Intl
Sep 23
SEA8:59 pmSeattle/Tacoma Intl
16h 53m
1 stop
IAD4:52 pmWashington, D.C. Dulles Intl
$296
Find similar
Alaska Airlines
Sep 18
IAD7:00 amWashington, D.C. Dulles Intl
5h 40m
SEA9:40 amSeattle/Tacoma Intl
Sep 24
SEA11:30 pmSeattle/Tacoma Intl
5h 03m
IAD7:33 amWashington, D.C. Dulles Intl
$297
Find similar

Sun Country Air flights from Washington, D.C. Dulles Intl Airport to Seattle

Our best Sun Country Air deals on Washington, D.C. Dulles Intl Airport to Seattle flight tickets
Sun Country Air
Oct 31
IAD11:52 amWashington, D.C. Dulles Intl
8h 09m
1 stop
SEA5:01 pmSeattle/Tacoma Intl
Nov 6
SEA6:24 pmSeattle/Tacoma Intl
13h 35m
1 stop
IAD10:59 amWashington, D.C. Dulles Intl
$289
Find similar
Sun Country Air
Oct 31
IAD11:52 amWashington, D.C. Dulles Intl
8h 09m
1 stop
SEA5:01 pmSeattle/Tacoma Intl
Nov 6
SEA6:24 pmSeattle/Tacoma Intl
13h 35m
1 stop
IAD10:59 amWashington, D.C. Dulles Intl
$305
Find similar
Sun Country Air
Nov 20
IAD12:50 pmWashington, D.C. Dulles Intl
7h 19m
1 stop
SEA5:09 pmSeattle/Tacoma Intl
Nov 25
SEA6:30 pmSeattle/Tacoma Intl
14h 24m
1 stop
IAD11:54 amWashington, D.C. Dulles Intl
$319
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Washington, D.C. Dulles Intl Airport 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, momondo users made 832,500 searches. Data last updated August 14, 2025.
Use the filters below to find and compare flights from Washington, D.C. Dulles Intl Airport to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sun 9/7

1:55 pm-12:30 am

2 stops13h 35m

Seattle/Tacoma Intl

Thu 9/11

12:05 pm-9:17 am

2 stops18h 12m

$236

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 9/12

6:10 am-5:33 pm

2 stops14h 23m

Seattle/Tacoma Intl

Sat 9/13

7:00 am-11:55 pm

2 stops13h 55m

$242

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 9/20

6:09 pm-8:56 pm

Nonstop5h 47m

Seattle/Tacoma Intl

Sat 9/27

4:20 pm-12:23 am

Nonstop5h 03m

$252

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 9/4

7:00 am-9:40 am

Nonstop5h 40m

Seattle/Tacoma Intl

Wed 9/10

4:20 pm-12:23 am

Nonstop5h 03m

$272

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 9/4

7:00 am-9:40 am

Nonstop5h 40m

Seattle/Tacoma Intl

Wed 9/10

11:30 pm-7:33 am

Nonstop5h 03m

$273

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 9/4

7:35 am-10:20 am

Nonstop5h 45m

Seattle/Tacoma Intl

Wed 9/10

9:55 pm-5:55 am

Nonstop5h 00m

$277

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 9/4

7:35 am-10:20 am

Nonstop5h 45m

Seattle/Tacoma Intl

Wed 9/10

9:55 pm-5:55 am

Nonstop5h 00m

$278

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 9/13

5:55 pm-8:42 pm

Nonstop5h 47m

Seattle/Tacoma Intl

Tue 9/16

7:34 pm-7:00 am

1 stop8h 26m

$287

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 9/5

5:55 pm-8:42 pm

Nonstop5h 47m

Seattle/Tacoma Intl

Sun 9/7

10:55 pm-6:58 am

Nonstop5h 03m

$295

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 9/9

5:52 pm-10:20 am

1 stop19h 28m

Seattle/Tacoma Intl

Tue 9/23

8:59 pm-4:52 pm

1 stop16h 53m

$296

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 Seattle from

How to get the cheapest flight ticket from Washington, D.C. Dulles Intl Airport to Seattle

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 Seattle?

In general, February is the cheapest month to fly from Washington, D.C. Dulles Intl Airport to Seattle. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $342. If you don’t want to visit Seattle in February, then you should wait until January to fly from Washington, D.C. Dulles Intl Airport, when ticket prices are also cheap, with an average price of $357.

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

On average, the least expensive day to fly to Seattle from Washington, D.C. Dulles Intl Airport is on a Tuesday. momondo users have found tickets for Tuesday departures for as low as $440. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday is the most expensive day to depart from Washington, D.C. Dulles Intl Airport because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $573.

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

Flying to Seattle from Washington, D.C. Dulles Intl Airport in the evening is the least expensive time of day to depart. momondo users have found prices as low as $419 when looking at flights departing in the evening. Flights to Seattle are more costly in the morning, with an average ticket price of $518. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

What is the cheapest Washington, D.C. Dulles Intl to Seattle/Tacoma Intl flight route?

Fly from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl for the best Washington, D.C. Dulles Intl - Seattle/Tacoma Intl flight prices

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

You are more likely to see cheaper flights to Seattle from Washington, D.C. Dulles Intl Airport when booking weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $407 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Seattle from Washington, D.C. Dulles Intl Airport for as low as $354 on momondo.

What cabin class options are available on Washington, D.C. Dulles Intl to Seattle/Tacoma Intl flights?

There are 4 cabin classes available to choose from on Washington, D.C. Dulles Intl to Seattle/Tacoma Intl flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have Washington, D.C. Dulles Intl Airport to Seattle flight prices changed over time?

As of August 2025, prices for Washington, D.C. Dulles Intl Airport to Seattle flights are approximately 10% cheaper when compared to flights at the same time last year.

When to book flights from Washington, D.C. Dulles Intl Airport to Seattle

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

Cheap Washington, D.C. Dulles Intl Airport to Seattle (IAD to SEA) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Washington, D.C. Dulles Intl Airport to Seattle

Best Price Found

$116

Fastest flight time

5h 40m

Direct flights

Every day

Airports in Seattle

1 airport
The best one-way flight to Seattle from Washington, D.C. Dulles Intl Airport in the past 72 hours is $116. The best round-trip flight deal from Washington, D.C. Dulles Intl Airport to Seattle found on momondo in the last 72 hours is $236.
The fastest flight from Washington, D.C. Dulles Intl Airport to Seattle takes 5h 40m
Direct flights go from Washington, D.C. Dulles Intl Airport to Seattle every day.
There is 1 airport near Seattle: Seattle/Tacoma Intl (SEA)
Search flight deals

  • How far is Washington, D.C. Dulles Intl to Seattle/Tacoma Intl by plane?

    The distance between Washington, D.C. Dulles Intl and Seattle/Tacoma Intl is about 2299.7 mi. A reasonable flight in good conditions will take 5h 40m.

  • When did momondo last update prices for flights from Washington, D.C. Dulles Intl Airport to Seattle/Tacoma Intl Airport?

    Prices for flights from Washington, D.C. Dulles Intl Airport to Seattle/Tacoma Intl Airport are updated daily.

  • How many operators does momondo search for flights from Washington, D.C. Dulles Intl Airport to Seattle/Tacoma Intl Airport?

  • How old do you have to be to fly from Washington, D.C. Dulles Intl Airport to Seattle/Tacoma Intl Airport?

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Washington, D.C. Dulles Intl Airport to Seattle/Tacoma Intl Airport.

  • What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?

    The travel and health documents required for your trip to Seattle/Tacoma Intl Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Seattle/Tacoma Intl Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

  • What is the most popular plane model from Washington, D.C. Dulles Intl Airport to Seattle?

  • What is the most popular airline from Washington, D.C. Dulles Intl Airport to Seattle?

Best airlines flying from Washington, D.C. Dulles Intl Airport to Seattle

Compare and see reviews for airlines that fly from Washington, D.C. Dulles Intl Airport to Seattle with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $111Free CancellationRating
5.8
3,219 reviews
Search Frontier flights
Hawaiian AirlinesPriceFrom $168Free CancellationRating
7.8
2,656 reviews
Search Hawaiian Airlines flights
DeltaPriceFrom $191Free CancellationRating
8.0
7,980 reviews
Search Delta flights
Alaska AirlinesPriceFrom $261Free CancellationRating
8.0
10,000 reviews
Search Alaska Airlines flights
United AirlinesPriceFrom $282Free CancellationRating
7.4
8,916 reviews
Search United Airlines flights
American AirlinesPriceFrom $321Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights

  • Delta Flights From Washington, D.C. Dulles Intl Airport to Seattle

    Across 7 Delta flights from Washington, D.C. Dulles Intl Airport to Seattle this week, the average price was $386, with the best Delta deals starting from $191 round-trip. 7,980 users have rated Delta on momondo, with an average score of 8.0/10.

  • Alaska Airlines Flights From Washington, D.C. Dulles Intl Airport to Seattle

    The best Alaska Airlines deal for Washington, D.C. Dulles Intl Airport to Seattle flight tickets found on momondo in the last 72 hours was $261, round-trip. It should be noted that an average Alaska Airlines flight deal for this route in this time was higher, at $423 round-trip. Alaska Airlines operates 13 flights out of Washington, D.C. Dulles Intl Airport into Seattle in an average week, so prices vary by time and availability. 10,000 Alaska Airlines reviews by users on momondo have scored the airline at 8.0/10.

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Leavenworth
Tacoma
SeaTac
Ocean Shores
Olympia
Renton
Kent
Lynnwood
Federal Way
Puyallup
Marysville
Tukwila
Kirkland
Lakewood
Centralia
Shoreline
Cle Elum
Fife
Westport
Redmond

Why use momondo?

Why should I use momondo to find a flight deal from Washington, D.C. to Seattle?

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from Washington, D.C. to Seattle for you.

Can I find flights from Washington, D.C. to Seattle with flexible booking policies on momondo?

Yes. momondo allows you to filter the results for Washington, D.C. to Seattle flights to just show those with flexible booking policies.

How can momondo help me find flights from Washington, D.C. to Seattle?

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 Washington, D.C. to Seattle.

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

Price alerts on flights to Seattle from Washington, D.C. are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.

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