Cheap flights from Seattle to Washington, D.C. from $124

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 Washington, D.C. departing on 5/7. 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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Cheap round-trip flights

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Alaska Airlines Logo
3:55 pm - 12:09 am
SEA
-
IAD
5h 14mnonstop
Alaska Airlines Logo
7:20 pm - 10:05 pm
IAD
-
SEA
5h 45mnonstop
$209Alaska Airlines
Fri, Apr 24 - Mon, May 4
United Airlines Logo
8:00 am - 4:11 pm
SEA
-
IAD
5h 11mnonstop
United Airlines Logo
5:41 pm - 11:46 pm
IAD
-
SEA
9h 05m
1 stop
$214United Airlines
Wed, Apr 1 - Mon, Apr 6
United Airlines Logo
2:39 pm - 12:32 am
SEA
-
IAD
6h 53m
1 stop
United Airlines Logo
5:55 pm - 8:53 pm
IAD
-
SEA
5h 58mnonstop
$215United Airlines
Thu, Apr 9 - Wed, Apr 15
Alaska Airlines Logo
7:40 pm - 5:41 pm
SEA
-
IAD
19h 01m
1 stop
Alaska Airlines Logo
6:47 pm - 9:26 am
IAD
-
SEA
17h 39m
1 stop
$217Alaska Airlines
Thu, May 7 - Sat, May 9
Delta Logo
3:59 pm - 11:55 pm
SEA
-
IAD
4h 56mnonstop
Delta Logo
7:00 am - 9:54 am
IAD
-
SEA
5h 54mnonstop
$218Delta
Wed, Apr 22 - Mon, Apr 27
United Airlines Logo
8:00 am - 4:11 pm
SEA
-
IAD
5h 11mnonstop
United Airlines Logo
5:20 pm - 10:33 pm
IAD
-
SEA
8h 13m
1 stop
$219United Airlines
Wed, Apr 1 - Sun, Apr 5
Alaska Airlines Logo
9:40 pm - 5:40 am
SEA
-
IAD
5h 00mnonstop
Alaska Airlines Logo
7:00 am - 9:53 am
IAD
-
SEA
5h 53mnonstop
$223Alaska Airlines
Sat, Mar 28 - Fri, Apr 3
Alaska Airlines Logo
9:40 pm - 5:40 am
SEA
-
IAD
5h 00mnonstop
Alaska Airlines Logo
7:00 am - 9:53 am
IAD
-
SEA
5h 53mnonstop
$224Alaska Airlines
Tue, Mar 31 - Fri, Apr 3
Delta Logo
1:30 pm - 10:59 pm
SEA
-
IAD
6h 29m
1 stop
Delta Logo
7:00 am - 10:03 am
IAD
-
SEA
6h 03mnonstop
$228Delta
Mon, Mar 30 - Sun, Apr 5
United Airlines Logo
7:00 am - 5:09 pm
SEA
-
IAD
7h 09m
1 stop
United Airlines Logo
6:15 am - 11:48 am
IAD
-
SEA
8h 33m
1 stop
$229United Airlines
Mon, Mar 30 - Sun, Apr 5

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

Our best American Airlines deals on Seattle to Washington, D.C. Dulles Intl Airport flight tickets
American Airlines
Apr 10
SEA11:41 amSeattle/Tacoma Intl
8h 45m
1 stop
IAD11:26 pmWashington, D.C. Dulles Intl
Apr 15
IAD6:25 amWashington, D.C. Dulles Intl
9h 08m
1 stop
SEA12:33 pmSeattle/Tacoma Intl
$243
American Airlines
Mar 15
SEA10:08 pmSeattle/Tacoma Intl
7h 40m
1 stop
IAD8:48 amWashington, D.C. Dulles Intl
Apr 4
IAD5:52 pmWashington, D.C. Dulles Intl
10h 03m
1 stop
SEA12:55 amSeattle/Tacoma Intl
$468
American Airlines
Mar 14
SEA10:08 pmSeattle/Tacoma Intl
7h 40m
1 stop
IAD8:48 amWashington, D.C. Dulles Intl
Mar 25
IAD5:00 amWashington, D.C. Dulles Intl
10h 51m
1 stop
SEA12:51 pmSeattle/Tacoma Intl
$599

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

Our best United Airlines deals on Seattle to Washington, D.C. Dulles Intl Airport flight tickets
United Airlines
Apr 1
SEA8:00 amSeattle/Tacoma Intl
5h 11m
IAD4:11 pmWashington, D.C. Dulles Intl
Apr 6
IAD5:41 pmWashington, D.C. Dulles Intl
9h 05m
1 stop
SEA11:46 pmSeattle/Tacoma Intl
$214
United Airlines
Apr 9
SEA2:39 pmSeattle/Tacoma Intl
6h 53m
1 stop
IAD12:32 amWashington, D.C. Dulles Intl
Apr 15
IAD5:55 pmWashington, D.C. Dulles Intl
5h 58m
SEA8:53 pmSeattle/Tacoma Intl
$215
United Airlines
Apr 1
SEA8:00 amSeattle/Tacoma Intl
5h 11m
IAD4:11 pmWashington, D.C. Dulles Intl
Apr 5
IAD5:20 pmWashington, D.C. Dulles Intl
8h 13m
1 stop
SEA10:33 pmSeattle/Tacoma Intl
$219

momondo Fare Finder

 
Customize your flight search to find flights from Seattle to Washington, D.C. Dulles Intl Airport 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 March 5, 2026.
Use the filters below to find and compare flights from Seattle to Washington, D.C. Dulles Intl Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 4/24

3:55 pm-12:09 am

Nonstop5h 14m

Washington, D.C. Dulles Intl

Mon 5/4

7:20 pm-10:05 pm

Nonstop5h 45m

$209

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 4/1

8:00 am-4:11 pm

Nonstop5h 11m

Washington, D.C. Dulles Intl

Mon 4/6

5:41 pm-11:46 pm

1 stop9h 05m

$214

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 4/9

2:39 pm-12:32 am

1 stop6h 53m

Washington, D.C. Dulles Intl

Wed 4/15

5:55 pm-8:53 pm

Nonstop5h 58m

$215

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 5/7

7:40 pm-5:41 pm

1 stop19h 01m

Washington, D.C. Dulles Intl

Sat 5/9

6:47 pm-9:26 am

1 stop17h 39m

$217
Quickest round-trip

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 4/22

3:59 pm-11:55 pm

Nonstop4h 56m

Washington, D.C. Dulles Intl

Mon 4/27

7:00 am-9:54 am

Nonstop5h 54m

$218

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 4/1

8:00 am-4:11 pm

Nonstop5h 11m

Washington, D.C. Dulles Intl

Sun 4/5

5:20 pm-10:33 pm

1 stop8h 13m

$219

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 3/28

9:40 pm-5:40 am

Nonstop5h 00m

Washington, D.C. Dulles Intl

Fri 4/3

7:00 am-9:53 am

Nonstop5h 53m

$223

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Tue 3/31

9:40 pm-5:40 am

Nonstop5h 00m

Washington, D.C. Dulles Intl

Fri 4/3

7:00 am-9:53 am

Nonstop5h 53m

$224

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Mon 3/30

1:30 pm-10:59 pm

1 stop6h 29m

Washington, D.C. Dulles Intl

Sun 4/5

7:00 am-10:03 am

Nonstop6h 03m

$228

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Mon 3/30

7:00 am-5:09 pm

1 stop7h 09m

Washington, D.C. Dulles Intl

Sun 4/5

6:15 am-11:48 am

1 stop8h 33m

$229

Flights are sorted by cheapest round-trip flights first.

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See travel insights to Washington, D.C. from

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

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 Washington, D.C. Dulles Intl Airport?

In general, October is the cheapest month to fly from Seattle to Washington, D.C. Dulles Intl Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $325. If you aren’t able to travel to Washington, D.C. Dulles Intl Airport during the month of October, then flying in February is also cheap. Prices for this month can be found on momondo for an average of $344.

What is the cheapest day to depart on your flight to Washington, D.C. Dulles Intl Airport?

Our data shows that Thursday is the least expensive day to fly to Washington, D.C. Dulles Intl Airport. Tickets to fly out on this day can be as low as $427. When flying out on a Sunday, the most expensive travel day of the week, you can expect to see flight prices from Seattle to Washington, D.C. Dulles Intl Airport for around $582.

What is the cheapest time of day to depart on your flight to Washington, D.C. Dulles Intl Airport?

Flying to Washington, D.C. Dulles Intl Airport from Seattle in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $327 when looking at flights departing in the afternoon. If you have a flexible travel schedule, then try to avoid flying in the morning when prices are $525 on average. Flights to Washington, D.C. Dulles Intl Airport from Seattle in the morning are generally more expensive because this time of day is more convenient for travelers’ schedules.

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

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

How far in advance should I book a flight to Washington, D.C. Dulles Intl Airport?

You are more likely to see cheaper flights to Washington, D.C. Dulles Intl Airport from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to Washington, D.C. Dulles Intl Airport for around $420 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Washington, D.C. Dulles Intl Airport from Seattle for as low as $318 on momondo.

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

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

Can stopping save me money on Seattle to Washington, D.C. Dulles Intl Airport flights?

You could potentially save up to 14% on your flight if you consider stops on a Seattle to Washington, D.C. Dulles Intl Airport flight.

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

As of March 2026, prices for Seattle to Washington, D.C. Dulles Intl Airport flights are approximately 14% cheaper when compared to flights at the same time last year.

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

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

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

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

Best Price Found

$206

Fastest flight time

4h 54m

Direct flights

Every day
The best one-way flight to Washington, D.C. Dulles Intl Airport from Seattle in the past 72 hours is $206. The best round-trip flight deal from Seattle to Washington, D.C. Dulles Intl Airport found on momondo in the last 72 hours is $335.
The fastest flight from Seattle to Washington, D.C. Dulles Intl Airport takes 4h 54m
Direct flights go from Seattle to Washington, D.C. Dulles Intl Airport every day.
  • How far is Seattle/Tacoma Intl to Washington, D.C. Dulles Intl by plane?

    There are 2299.7 mi between Seattle/Tacoma Intl and Washington, D.C. Dulles Intl. A reasonable flight in good conditions will take 4h 54m.

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

    Prices for flights from Seattle/Tacoma Intl Airport to Washington, D.C. Dulles Intl Airport are refreshed on a daily basis.

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

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

    The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Seattle/Tacoma Intl Airport to Washington, D.C. Dulles Intl Airport.

  • What documentation or ID do you need to fly to Washington, D.C. Dulles Intl Airport?

    The travel and health documents required for your trip to Washington, D.C. Dulles 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 Washington, D.C. Dulles 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 Seattle to Washington, D.C. Dulles Intl Airport?

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

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

Compare and see reviews for airlines that fly from Seattle to Washington, D.C. Dulles Intl Airport with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $126Free CancellationRating
5.7
3,041 reviews
Search Frontier flights
Hawaiian AirlinesPriceFrom $138Free CancellationRating
7.8
2,836 reviews
Search Hawaiian Airlines flights
DeltaPriceFrom $158Free CancellationRating
7.9
8,250 reviews
Search Delta flights
United AirlinesPriceFrom $219Free CancellationRating
7.4
9,388 reviews
Search United Airlines flights
Alaska AirlinesPriceFrom $241Free CancellationRating
8.0
11,987 reviews
Search Alaska Airlines flights
American AirlinesPriceFrom $406Free CancellationRating
7.1
11,382 reviews
Search American Airlines flights
  • Alaska Airlines Flights From Seattle to Washington, D.C. Dulles Intl Airport

    Across 6 Alaska Airlines flights from Seattle to Washington, D.C. Dulles Intl Airport this week, the average price was $422, with the best Alaska Airlines deals starting from $241 round-trip. 11,987 users have rated Alaska Airlines on momondo, with an average score of 8.0/10.

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

    Delta is also a popular choice for this route. Delta flight deals for Seattle to Washington, D.C. Dulles Intl Airport start from as low as $158 round-trip, depending on your selected dates, with average Delta deals seen on momondo around $330. Delta operates 4 flights to Washington, D.C. Dulles Intl Airport from Seattle in an average week. Users have rated it 7.9/10 across 8,250 reviews.

Traveling to a place near Washington, D.C.?

Book flights to Washington, D.C. if you plan to visit one of these locations
Alexandria
National Harbor
Gettysburg
Arlington
Winchester
Waldorf
Woodbridge
Colonial Beach
Laurel
Towson
Silver Spring
Gaithersburg
Fredericksburg
Rockville
Tysons
Manassas
Springfield
Bethesda
Fairfax
Sterling

Why use momondo?

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

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from Seattle to Washington, D.C.. Millions of users trust and use momondo every year so you are in good hands.

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

Yes. All flights to Washington, D.C. 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 Washington, D.C.?

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 Washington, D.C..

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

If you are not ready to book a flight from Seattle to Washington, D.C. now, use our insights above to find helpful tips or alternatively set up a price alert, where momondo will track prices on flights to Washington, D.C. and let you know when they change.

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1 adult
Sat 4/4
Sat 4/11

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