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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from $138

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 1/15. 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

Enter your travel dates to find the best prices.
Alaska Airlines Logo
6:04 pm - 9:08 pmIAD-SEA
6h 04mnonstop
Alaska Airlines Logo
8:30 am - 4:26 pmSEA-IAD
4h 56mnonstop
$236Alaska Airlines
Find Deal
Thu, Feb 5 - Mon, Feb 9
Alaska Airlines Logo
7:34 am - 10:35 amIAD-SEA
6h 01mnonstop
Alaska Airlines Logo
10:11 pm - 6:06 amSEA-IAD
4h 55mnonstop
$238Alaska Airlines
Find Deal
Fri, Dec 5 - Mon, Dec 15
Delta Logo
7:15 am - 10:12 amIAD-SEA
5h 57mnonstop
Delta Logo
3:30 pm - 11:27 pmSEA-IAD
4h 57mnonstop
$239Delta
Find Deal
Mon, Dec 8 - Thu, Dec 11
United Airlines Logo
5:55 pm - 8:54 pmIAD-SEA
5h 59mnonstop
United Airlines Logo
8:10 am - 4:18 pmSEA-IAD
5h 08mnonstop
$240United Airlines
Find Deal
Sat, Dec 6 - Sat, Dec 13
United Airlines Logo
5:55 pm - 8:57 pmIAD-SEA
6h 02mnonstop
United Airlines Logo
8:10 am - 4:16 pmSEA-IAD
5h 06mnonstop
$241United Airlines
Find Deal
Thu, Feb 5 - Mon, Feb 9
Delta Logo
7:15 am - 10:12 amIAD-SEA
5h 57mnonstop
Delta Logo
3:30 pm - 11:27 pmSEA-IAD
4h 57mnonstop
$243Delta
Find Deal
Wed, Dec 3 - Sat, Dec 6
Alaska Airlines Logo
7:34 am - 10:35 amIAD-SEA
6h 01mnonstop
Alaska Airlines Logo
8:30 am - 4:26 pmSEA-IAD
4h 56mnonstop
$244Alaska Airlines
Find Deal
Wed, Dec 17 - Sat, Jan 24
United Airlines Logo
5:17 pm - 10:43 pmIAD-SEA
8h 26m1 stop
United Airlines Logo
8:10 am - 4:16 pmSEA-IAD
5h 06mnonstop
$245United Airlines
Find Deal
Sun, Feb 8 - Wed, Feb 11
United Airlines Logo
8:25 am - 3:44 pmIAD-SEA
10h 19m1 stop
United Airlines Logo
8:10 am - 4:16 pmSEA-IAD
5h 06mnonstop
$247United Airlines
Find Deal
Fri, Jan 9 - Sun, Jan 11
Alaska Airlines Logo
6:30 pm - 9:30 pmIAD-SEA
6h 00mnonstop
Alaska Airlines Logo
7:59 pm - 5:30 pmSEA-IAD
18h 31m1 stop
$248Alaska Airlines
Find Deal
Mon, Dec 8 - Tue, Dec 9

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

Our best United Airlines deals on Washington, D.C. Dulles Intl Airport to Seattle flight tickets
United Airlines
Dec 6
IAD5:55 pmWashington, D.C. Dulles Intl
5h 59m
SEA8:54 pmSeattle/Tacoma Intl
Dec 13
SEA8:10 amSeattle/Tacoma Intl
5h 08m
IAD4:18 pmWashington, D.C. Dulles Intl
$240
Find similar
United Airlines
Feb 8
IAD5:17 pmWashington, D.C. Dulles Intl
8h 26m
1 stop
SEA10:43 pmSeattle/Tacoma Intl
Feb 11
SEA8:10 amSeattle/Tacoma Intl
5h 06m
IAD4:16 pmWashington, D.C. Dulles Intl
$245
Find similar
United Airlines
Feb 26
IAD1:02 pmWashington, D.C. Dulles Intl
9h 01m
1 stop
SEA7:03 pmSeattle/Tacoma Intl
Mar 1
SEA12:18 pmSeattle/Tacoma Intl
8h 03m
1 stop
IAD11:21 pmWashington, D.C. Dulles Intl
$246
Find similar

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

Our best American Airlines deals on Washington, D.C. Dulles Intl Airport to Seattle flight tickets
American Airlines
Dec 11
IAD6:25 amWashington, D.C. Dulles Intl
9h 22m
1 stop
SEA12:47 pmSeattle/Tacoma Intl
Dec 18
SEA5:23 amSeattle/Tacoma Intl
8h 54m
1 stop
IAD5:17 pmWashington, D.C. Dulles Intl
$263
Find similar
American Airlines
Nov 21
IAD1:58 pmWashington, D.C. Dulles Intl
8h 46m
1 stop
SEA7:44 pmSeattle/Tacoma Intl
Dec 3
SEA12:41 pmSeattle/Tacoma Intl
7h 27m
1 stop
IAD11:08 pmWashington, D.C. Dulles Intl
$517
Find similar
American Airlines
Nov 22
IAD9:12 amWashington, D.C. Dulles Intl
13h 32m
1 stop
SEA7:44 pmSeattle/Tacoma Intl
Dec 1
SEA10:07 pmSeattle/Tacoma Intl
12h 28m
1 stop
IAD1:35 pmWashington, D.C. Dulles Intl
$640
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 November 13, 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

Thu 2/5

6:04 pm-9:08 pm

Nonstop6h 04m

Seattle/Tacoma Intl

Mon 2/9

8:30 am-4:26 pm

Nonstop4h 56m

$236

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 12/5

7:34 am-10:35 am

Nonstop6h 01m

Seattle/Tacoma Intl

Mon 12/15

10:11 pm-6:06 am

Nonstop4h 55m

$238

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 12/8

7:15 am-10:12 am

Nonstop5h 57m

Seattle/Tacoma Intl

Thu 12/11

3:30 pm-11:27 pm

Nonstop4h 57m

$239

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 12/6

5:55 pm-8:54 pm

Nonstop5h 59m

Seattle/Tacoma Intl

Sat 12/13

8:10 am-4:18 pm

Nonstop5h 08m

$240

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 2/5

5:55 pm-8:57 pm

Nonstop6h 02m

Seattle/Tacoma Intl

Mon 2/9

8:10 am-4:16 pm

Nonstop5h 06m

$241

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 12/3

7:15 am-10:12 am

Nonstop5h 57m

Seattle/Tacoma Intl

Sat 12/6

3:30 pm-11:27 pm

Nonstop4h 57m

$243

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 12/17

7:34 am-10:35 am

Nonstop6h 01m

Seattle/Tacoma Intl

Sat 1/24

8:30 am-4:26 pm

Nonstop4h 56m

$244

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sun 2/8

5:17 pm-10:43 pm

1 stop8h 26m

Seattle/Tacoma Intl

Wed 2/11

8:10 am-4:16 pm

Nonstop5h 06m

$245

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 1/9

8:25 am-3:44 pm

1 stop10h 19m

Seattle/Tacoma Intl

Sun 1/11

8:10 am-4:16 pm

Nonstop5h 06m

$247

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 12/8

6:30 pm-9:30 pm

Nonstop6h 00m

Seattle/Tacoma Intl

Tue 12/9

7:59 pm-5:30 pm

1 stop18h 31m

$248

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 $352. 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 $361.

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 $438. 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 $579.

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 $422 when looking at flights departing in the evening. Flights to Seattle are more costly in the morning, with an average ticket price of $522. 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 $412 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 $340 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 November 2025, prices for Washington, D.C. Dulles Intl Airport to Seattle flights are approximately 4% 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

$216

Fastest flight time

5h 47m

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 $216. The best round-trip flight deal from Washington, D.C. Dulles Intl Airport to Seattle found on momondo in the last 72 hours is $361.
The fastest flight from Washington, D.C. Dulles Intl Airport to Seattle takes 5h 47m
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 57m.

  • 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
3,114 reviews
Search Frontier flights
Hawaiian AirlinesPriceFrom $149Free CancellationRating
7.8
2,809 reviews
Search Hawaiian Airlines flights
DeltaPriceFrom $184Free CancellationRating
7.9
8,007 reviews
Search Delta flights
Alaska AirlinesPriceFrom $275Free CancellationRating
8.0
11,281 reviews
Search Alaska Airlines flights
United AirlinesPriceFrom $278Free CancellationRating
7.4
9,015 reviews
Search United Airlines flights
American AirlinesPriceFrom $321Free CancellationRating
7.2
11,050 reviews
Search American Airlines flights

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

    Across 4 Alaska Airlines flights from Washington, D.C. Dulles Intl Airport to Seattle this week, the average price was $435, with the best Alaska Airlines deals starting from $275 round-trip. 11,281 users have rated Alaska Airlines on momondo, with an average score of 8.0/10.

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

    The best Delta deal for Washington, D.C. Dulles Intl Airport to Seattle flight tickets found on momondo in the last 72 hours was $184, round-trip. It should be noted that an average Delta flight deal for this route in this time was higher, at $378 round-trip. Delta operates 7 flights out of Washington, D.C. Dulles Intl Airport into Seattle in an average week, so prices vary by time and availability. 8,007 Delta reviews by users on momondo have scored the airline at 7.9/10.

Traveling to a place near Seattle?

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

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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