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Cheap flights from Seattle to Washington, D.C. from $134

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 3/18. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Cheap round-trip flights

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United Airlines Logo
5:00 am - 3:12 pmSEA-IAD
7h 12m1 stop
United Airlines Logo
5:17 pm - 10:43 pmIAD-SEA
8h 26m1 stop
$233United Airlines
Find Deal
Wed, Jan 7 - Sun, Jan 18
United Airlines Logo
7:12 pm - 6:47 amSEA-IAD
8h 35m1 stop
United Airlines Logo
5:55 pm - 8:57 pmIAD-SEA
6h 02mnonstop
$235United Airlines
Find Deal
Tue, Dec 30 - Sat, Jan 10
Alaska Airlines Logo
10:11 pm - 6:06 amSEA-IAD
4h 55mnonstop
Alaska Airlines Logo
7:34 am - 10:35 amIAD-SEA
6h 01mnonstop
$236Alaska Airlines
Find Deal
Fri, Dec 12 - Tue, Dec 16
Delta Logo
1:40 pm - 11:29 pmSEA-IAD
6h 49m1 stop
Delta Logo
7:05 am - 2:59 pmIAD-SEA
10h 54m1 stop
$238Delta
Find Deal
Fri, Dec 12 - Tue, Dec 16
Delta Logo
3:20 pm - 11:10 pmSEA-IAD
4h 50mnonstop
Delta Logo
7:30 am - 10:29 amIAD-SEA
5h 59mnonstop
$239Delta
Find Deal
Sun, Feb 15 - Thu, Feb 19
Alaska Airlines Logo
9:27 am - 5:20 pmSEA-IAD
4h 53mnonstop
Alaska Airlines Logo
6:20 pm - 9:28 amIAD-SEA
18h 08m1 stop
$248Alaska Airlines
Find Deal
Wed, Feb 18 - Sun, Feb 22
Delta Logo
3:30 pm - 11:27 pmSEA-IAD
4h 57mnonstop
Delta Logo
6:00 am - 10:40 amIAD-SEA
7h 40m1 stop
$249Delta
Find Deal
Fri, Dec 12 - Sun, Dec 14
United Airlines Logo
5:10 pm - 6:47 amSEA-IAD
10h 37m1 stop
United Airlines Logo
5:55 pm - 8:57 pmIAD-SEA
6h 02mnonstop
$250United Airlines
Find Deal
Fri, Jan 16 - Mon, Jan 19
United Airlines Logo
5:00 am - 3:13 pmSEA-IAD
7h 13m1 stop
United Airlines Logo
5:17 pm - 10:43 pmIAD-SEA
8h 26m1 stop
$252United Airlines
Find Deal
Sat, Jan 10 - Thu, Jan 15
Alaska Airlines Logo
8:11 pm - 5:27 pmSEA-IAD
18h 16m1 stop
Alaska Airlines Logo
6:20 pm - 9:28 amIAD-SEA
18h 08m1 stop
$256Alaska Airlines
Find Deal
Wed, Feb 18 - Sun, Feb 22

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
Feb 7
SEA6:00 amSeattle/Tacoma Intl
7h 31m
1 stop
IAD4:31 pmWashington, D.C. Dulles Intl
Feb 18
IAD3:11 pmWashington, D.C. Dulles Intl
8h 58m
1 stop
SEA9:09 pmSeattle/Tacoma Intl
$262
Find similar
American Airlines
Jan 5
SEA10:13 pmSeattle/Tacoma Intl
9h 45m
1 stop
IAD10:58 amWashington, D.C. Dulles Intl
Jan 9
IAD6:00 amWashington, D.C. Dulles Intl
10h 17m
1 stop
SEA1:17 pmSeattle/Tacoma Intl
$284
Find similar
American Airlines
Feb 19
SEA12:59 amSeattle/Tacoma Intl
18h 52m
1 stop
IAD10:51 pmWashington, D.C. Dulles Intl
Feb 24
IAD3:11 pmWashington, D.C. Dulles Intl
8h 58m
1 stop
SEA9:09 pmSeattle/Tacoma Intl
$291
Find similar

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

Our best Southwest deals on Seattle to Washington, D.C. Dulles Intl Airport flight tickets
Southwest
Dec 12
SEA5:15 amSeattle/Tacoma Intl
8h 50m
1 stop
IAD5:05 pmWashington, D.C. Dulles Intl
Dec 13
IAD3:55 pmWashington, D.C. Dulles Intl
8h 05m
1 stop
SEA9:00 pmSeattle/Tacoma Intl
$268
Find similar
Southwest
Dec 11
SEA5:15 amSeattle/Tacoma Intl
8h 50m
1 stop
IAD5:05 pmWashington, D.C. Dulles Intl
Dec 13
IAD3:55 pmWashington, D.C. Dulles Intl
8h 05m
1 stop
SEA9:00 pmSeattle/Tacoma Intl
$313
Find similar
Southwest
Jan 7
SEA8:45 amSeattle/Tacoma Intl
10h 10m
2 stops
IAD9:55 pmWashington, D.C. Dulles Intl
Jan 18
IAD5:30 pmWashington, D.C. Dulles Intl
8h 00m
1 stop
SEA10:30 pmSeattle/Tacoma Intl
$318
Find similar

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 November 22, 2025.
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

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 1/7

5:00 am-3:12 pm

1 stop7h 12m

Washington, D.C. Dulles Intl

Sun 1/18

5:17 pm-10:43 pm

1 stop8h 26m

$233

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Tue 12/30

7:12 pm-6:47 am

1 stop8h 35m

Washington, D.C. Dulles Intl

Sat 1/10

5:55 pm-8:57 pm

Nonstop6h 02m

$235

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 12/12

10:11 pm-6:06 am

Nonstop4h 55m

Washington, D.C. Dulles Intl

Tue 12/16

7:34 am-10:35 am

Nonstop6h 01m

$236

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 12/12

1:40 pm-11:29 pm

1 stop6h 49m

Washington, D.C. Dulles Intl

Tue 12/16

7:05 am-2:59 pm

1 stop10h 54m

$238

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sun 2/15

3:20 pm-11:10 pm

Nonstop4h 50m

Washington, D.C. Dulles Intl

Thu 2/19

7:30 am-10:29 am

Nonstop5h 59m

$239

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 2/18

9:27 am-5:20 pm

Nonstop4h 53m

Washington, D.C. Dulles Intl

Sun 2/22

6:20 pm-9:28 am

1 stop18h 08m

$248

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 12/12

3:30 pm-11:27 pm

Nonstop4h 57m

Washington, D.C. Dulles Intl

Sun 12/14

6:00 am-10:40 am

1 stop7h 40m

$249

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 1/16

5:10 pm-6:47 am

1 stop10h 37m

Washington, D.C. Dulles Intl

Mon 1/19

5:55 pm-8:57 pm

Nonstop6h 02m

$250

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 1/10

5:00 am-3:13 pm

1 stop7h 13m

Washington, D.C. Dulles Intl

Thu 1/15

5:17 pm-10:43 pm

1 stop8h 26m

$252

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 2/18

8:11 pm-5:27 pm

1 stop18h 16m

Washington, D.C. Dulles Intl

Sun 2/22

6:20 pm-9:28 am

1 stop18h 08m

$256

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 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 Wednesday 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 $447. 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 $632.

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 $356 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 $545 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 $406 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 $289 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?

No. A direct flight is the cheapest option for a flight between Seattle to Washington, D.C. Dulles Intl Airport.

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

As of November 2025, prices for Seattle to Washington, D.C. Dulles Intl Airport flights are approximately 1% 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

$193

Fastest flight time

4h 50m

Direct flights

Every day
The best one-way flight to Washington, D.C. Dulles Intl Airport from Seattle in the past 72 hours is $193. The best round-trip flight deal from Seattle to Washington, D.C. Dulles Intl Airport found on momondo in the last 72 hours is $337.
The fastest flight from Seattle to Washington, D.C. Dulles Intl Airport takes 4h 50m
Direct flights go from Seattle to Washington, D.C. Dulles Intl Airport every day.
Search flight deals

  • 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 50m.

  • 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
Hawaiian AirlinesPriceFrom $143Free CancellationRating
7.8
2,813 reviews
Search Hawaiian Airlines flights
FrontierPriceFrom $188Free CancellationRating
5.8
3,100 reviews
Search Frontier flights
DeltaPriceFrom $192Free CancellationRating
7.9
8,001 reviews
Search Delta flights
United AirlinesPriceFrom $275Free CancellationRating
7.4
9,034 reviews
Search United Airlines flights
Alaska AirlinesPriceFrom $280Free CancellationRating
8.0
11,329 reviews
Search Alaska Airlines flights
American AirlinesPriceFrom $336Free CancellationRating
7.2
11,047 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 $426, with the best Alaska Airlines deals starting from $280 round-trip. 11,329 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 $192 round-trip, depending on your selected dates, with average Delta deals seen on momondo around $380. Delta operates 2 flights to Washington, D.C. Dulles Intl Airport from Seattle in an average week. Users have rated it 7.9/10 across 8,001 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
Woodbridge
Waldorf
Tysons
Laurel
Colonial Beach
Silver Spring
Fredericksburg
Harpers Ferry
Towson
Rockville
Reston
Manassas
Gaithersburg
Fairfax
Glen Burnie

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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