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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from $120

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 1/31. 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.
Delta Logo
7:30 am - 10:29 am
IAD
-
SEA
5h 59mnonstop
Delta Logo
3:20 pm - 11:10 pm
SEA
-
IAD
4h 50mnonstop
$199Delta
Sat, Feb 28 - Tue, Mar 3
United Airlines Logo
5:17 pm - 10:43 pm
IAD
-
SEA
8h 26m1 stop
United Airlines Logo
8:10 am - 4:16 pm
SEA
-
IAD
5h 06mnonstop
$204United Airlines
Thu, Jan 22 - Sun, Jan 25
United Airlines Logo
5:17 pm - 10:43 pm
IAD
-
SEA
8h 26m1 stop
United Airlines Logo
8:10 am - 4:16 pm
SEA
-
IAD
5h 06mnonstop
$205United Airlines
Thu, Jan 29 - Thu, Feb 5
Alaska Airlines Logo
7:05 am - 10:05 am
IAD
-
SEA
6h 00mnonstop
Alaska Airlines Logo
9:45 pm - 5:40 am
SEA
-
IAD
4h 55mnonstop
$209Alaska Airlines
Wed, Feb 25 - Fri, Mar 6
United Airlines Logo
5:55 pm - 8:56 pm
IAD
-
SEA
6h 01mnonstop
United Airlines Logo
12:12 pm - 11:21 pm
SEA
-
IAD
8h 09m1 stop
$214United Airlines
Thu, Feb 12 - Sun, Feb 15
Alaska Airlines Logo
7:05 am - 10:05 am
IAD
-
SEA
6h 00mnonstop
Alaska Airlines Logo
9:45 pm - 5:40 am
SEA
-
IAD
4h 55mnonstop
$218Alaska Airlines
Sat, Feb 14 - Sun, Feb 22
Delta Logo
7:00 am - 2:45 pm
IAD
-
SEA
10h 45m1 stop
Delta Logo
3:20 pm - 11:10 pm
SEA
-
IAD
4h 50mnonstop
$219Delta
Thu, Jan 22 - Sun, Jan 25
American Airlines Logo
1:08 pm - 7:04 pm
IAD
-
SEA
8h 56m1 stop
American Airlines Logo
7:00 am - 5:16 pm
SEA
-
IAD
7h 16m1 stop
$220American Airlines
Thu, Jan 22 - Wed, Jan 28
United Airlines Logo
1:05 pm - 6:16 pm
IAD
-
SEA
8h 11m1 stop
United Airlines Logo
12:12 pm - 11:21 pm
SEA
-
IAD
8h 09m1 stop
$224United Airlines
Tue, Feb 10 - Sun, Feb 15
Southwest Logo
9:05 am - 5:50 pm
IAD
-
SEA
11h 45m1 stop
Southwest Logo
5:15 am - 4:50 pm
SEA
-
IAD
8h 35m1 stop
$225Southwest
Tue, Jan 27 - Fri, Jan 30

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

Our best Delta deals on Washington, D.C. Dulles Intl Airport to Seattle flight tickets
Delta
Feb 28
IAD7:30 amWashington, D.C. Dulles Intl
5h 59m
SEA10:29 amSeattle/Tacoma Intl
Mar 7
SEA3:20 pmSeattle/Tacoma Intl
4h 50m
IAD11:10 pmWashington, D.C. Dulles Intl
$199
Find similar
Delta
Jan 22
IAD7:30 amWashington, D.C. Dulles Intl
5h 59m
SEA10:29 amSeattle/Tacoma Intl
Jan 28
SEA1:38 pmSeattle/Tacoma Intl
7h 10m
1 stop
IAD11:48 pmWashington, D.C. Dulles Intl
$219
Find similar
Delta
Feb 27
IAD7:30 amWashington, D.C. Dulles Intl
5h 59m
SEA10:29 amSeattle/Tacoma Intl
Mar 5
SEA3:20 pmSeattle/Tacoma Intl
4h 50m
IAD11:10 pmWashington, D.C. Dulles Intl
$239
Find similar

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
Jan 22
IAD5:17 pmWashington, D.C. Dulles Intl
8h 26m
1 stop
SEA10:43 pmSeattle/Tacoma Intl
Jan 25
SEA8:10 amSeattle/Tacoma Intl
5h 06m
IAD4:16 pmWashington, D.C. Dulles Intl
$204
Find similar
United Airlines
Jan 29
IAD5:17 pmWashington, D.C. Dulles Intl
8h 26m
1 stop
SEA10:43 pmSeattle/Tacoma Intl
Feb 2
SEA8:10 amSeattle/Tacoma Intl
5h 06m
IAD4:16 pmWashington, D.C. Dulles Intl
$205
Find similar
United Airlines
Feb 12
IAD5:55 pmWashington, D.C. Dulles Intl
6h 01m
SEA8:56 pmSeattle/Tacoma Intl
Feb 15
SEA8:17 amSeattle/Tacoma Intl
5h 02m
IAD4:19 pmWashington, D.C. Dulles Intl
$209
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 January 2, 2026.
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

Sat 2/28

7:30 am-10:29 am

Nonstop5h 59m

Seattle/Tacoma Intl

Tue 3/3

3:20 pm-11:10 pm

Nonstop4h 50m

$199

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 1/22

5:17 pm-10:43 pm

1 stop8h 26m

Seattle/Tacoma Intl

Sun 1/25

8:10 am-4:16 pm

Nonstop5h 06m

$204

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 1/29

5:17 pm-10:43 pm

1 stop8h 26m

Seattle/Tacoma Intl

Thu 2/5

8:10 am-4:16 pm

Nonstop5h 06m

$205

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 2/25

7:05 am-10:05 am

Nonstop6h 00m

Seattle/Tacoma Intl

Fri 3/6

9:45 pm-5:40 am

Nonstop4h 55m

$209

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 2/12

5:55 pm-8:56 pm

Nonstop6h 01m

Seattle/Tacoma Intl

Sun 2/15

12:12 pm-11:21 pm

1 stop8h 09m

$214

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 2/14

7:05 am-10:05 am

Nonstop6h 00m

Seattle/Tacoma Intl

Sun 2/22

9:45 pm-5:40 am

Nonstop4h 55m

$218

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 1/22

7:00 am-2:45 pm

1 stop10h 45m

Seattle/Tacoma Intl

Sun 1/25

3:20 pm-11:10 pm

Nonstop4h 50m

$219

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 1/22

1:08 pm-7:04 pm

1 stop8h 56m

Seattle/Tacoma Intl

Wed 1/28

7:00 am-5:16 pm

1 stop7h 16m

$220

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 2/10

1:05 pm-6:16 pm

1 stop8h 11m

Seattle/Tacoma Intl

Sun 2/15

12:12 pm-11:21 pm

1 stop8h 09m

$224

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 1/27

9:05 am-5:50 pm

1 stop11h 45m

Seattle/Tacoma Intl

Fri 1/30

5:15 am-4:50 pm

1 stop8h 35m

$225

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, January 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 $296. If you don’t want to visit Seattle in January, then you should wait until February 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 $436. 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 $425 when looking at flights departing in the evening. Flights to Seattle are more costly in the morning, with an average ticket price of $512. 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 $401 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 $321 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 January 2026, prices for Washington, D.C. Dulles Intl Airport to Seattle flights are approximately 9% more expensive 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

$233

Fastest flight time

5h 35m

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 $233. The best round-trip flight deal from Washington, D.C. Dulles Intl Airport to Seattle found on momondo in the last 72 hours is $326.
The fastest flight from Washington, D.C. Dulles Intl Airport to Seattle takes 5h 35m
Direct flights go from Washington, D.C. Dulles Intl Airport to Seattle every day.
There is 1 airport in Seattle. From Washington, D.C. Dulles Intl Airport there are direct flights to 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 35m.

  • 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
5.7
3,066 reviews
Search Frontier flights
Hawaiian AirlinesPriceFrom $149Free CancellationRating
7.8
2,823 reviews
Search Hawaiian Airlines flights
DeltaPriceFrom $176Free CancellationRating
7.9
8,021 reviews
Search Delta flights
Alaska AirlinesPriceFrom $258Free CancellationRating
8.0
11,599 reviews
Search Alaska Airlines flights
United AirlinesPriceFrom $258Free CancellationRating
7.4
9,133 reviews
Search United Airlines flights
American AirlinesPriceFrom $336Free CancellationRating
7.2
11,075 reviews
Search American Airlines flights

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

    Across 3 Alaska Airlines flights from Washington, D.C. Dulles Intl Airport to Seattle this week, the average price was $429, with the best Alaska Airlines deals starting from $258 round-trip. 11,599 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 $176, round-trip. It should be noted that an average Delta flight deal for this route in this time was higher, at $377 round-trip. Delta operates 3 flights out of Washington, D.C. Dulles Intl Airport into Seattle in an average week, so prices vary by time and availability. 8,021 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
Marysville
Puyallup
Redmond
Tukwila
Federal Way
Cle Elum
Lakewood
Centralia
Fife
Westport
Kirkland
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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