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Cheap flights from Seattle to Washington, D.C. 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 Seattle to Washington, D.C. departing on 2/4. 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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0 bags

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Cheap round-trip flights

Enter your travel dates to find the best prices.
Alaska Airlines Logo
8:30 am - 4:26 pm
SEA
-
IAD
4h 56mnonstop
Alaska Airlines Logo
6:04 pm - 9:08 pm
IAD
-
SEA
6h 04mnonstop
$199Alaska Airlines
Fri, Jan 30 - Tue, Feb 3
Southwest Logo
5:15 am - 4:00 pm
SEA
-
IAD
7h 45m1 stop
Southwest Logo
5:40 pm - 10:50 pm
IAD
-
SEA
8h 10m1 stop
$202Southwest
Thu, Feb 5 - Mon, Feb 9
United Airlines Logo
12:43 pm - 11:21 pm
SEA
-
IAD
7h 38m1 stop
United Airlines Logo
5:55 pm - 8:56 pm
IAD
-
SEA
6h 01mnonstop
$205United Airlines
Thu, Feb 26 - Sun, Mar 1
American Airlines Logo
8:35 am - 9:17 pm
SEA
-
IAD
9h 42m1 stop
American Airlines Logo
1:08 pm - 7:04 pm
IAD
-
SEA
8h 56m1 stop
$208American Airlines
Fri, Jan 30 - Tue, Feb 3
Alaska Airlines Logo
9:45 pm - 5:40 am
SEA
-
IAD
4h 55mnonstop
Alaska Airlines Logo
7:05 am - 10:05 am
IAD
-
SEA
6h 00mnonstop
$209Alaska Airlines
Mon, Feb 23 - Tue, Mar 3
Southwest Logo
5:15 am - 4:50 pm
SEA
-
IAD
8h 35m1 stop
Southwest Logo
4:30 pm - 11:05 pm
IAD
-
SEA
9h 35m1 stop
$211Southwest
Fri, Jan 30 - Mon, Feb 2
United Airlines Logo
12:42 pm - 11:21 pm
SEA
-
IAD
7h 39m1 stop
United Airlines Logo
5:55 pm - 8:56 pm
IAD
-
SEA
6h 01mnonstop
$215United Airlines
Sat, Feb 14 - Thu, Mar 12
Delta Logo
3:55 pm - 11:49 pm
SEA
-
IAD
4h 54mnonstop
Delta Logo
7:00 am - 10:03 am
IAD
-
SEA
6h 03mnonstop
$218Delta
Tue, Mar 31 - Tue, Apr 7
United Airlines Logo
8:17 am - 4:19 pm
SEA
-
IAD
5h 02mnonstop
United Airlines Logo
3:58 pm - 9:12 pm
IAD
-
SEA
8h 14m1 stop
$219United Airlines
Thu, Feb 19 - Tue, Feb 24
American Airlines Logo
12:45 pm - 11:12 pm
SEA
-
IAD
7h 27m1 stop
American Airlines Logo
1:08 pm - 7:04 pm
IAD
-
SEA
8h 56m1 stop
$220American Airlines
Thu, Jan 29 - Wed, Feb 4

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
Jan 30
SEA8:10 amSeattle/Tacoma Intl
5h 06m
IAD4:16 pmWashington, D.C. Dulles Intl
Feb 1
IAD5:55 pmWashington, D.C. Dulles Intl
6h 02m
SEA8:57 pmSeattle/Tacoma Intl
$199
Find similar
United Airlines
Feb 26
SEA12:43 pmSeattle/Tacoma Intl
7h 38m
1 stop
IAD11:21 pmWashington, D.C. Dulles Intl
Mar 1
IAD5:55 pmWashington, D.C. Dulles Intl
6h 01m
SEA8:56 pmSeattle/Tacoma Intl
$205
Find similar
United Airlines
Feb 14
SEA12:42 pmSeattle/Tacoma Intl
7h 39m
1 stop
IAD11:21 pmWashington, D.C. Dulles Intl
Mar 12
IAD5:55 pmWashington, D.C. Dulles Intl
6h 01m
SEA8:56 pmSeattle/Tacoma Intl
$215
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
Feb 5
SEA5:15 amSeattle/Tacoma Intl
7h 45m
1 stop
IAD4:00 pmWashington, D.C. Dulles Intl
Feb 9
IAD5:40 pmWashington, D.C. Dulles Intl
8h 10m
1 stop
SEA10:50 pmSeattle/Tacoma Intl
$202
Find similar
Southwest
Jan 30
SEA5:15 amSeattle/Tacoma Intl
8h 35m
1 stop
IAD4:50 pmWashington, D.C. Dulles Intl
Feb 2
IAD4:30 pmWashington, D.C. Dulles Intl
9h 35m
1 stop
SEA11:05 pmSeattle/Tacoma Intl
$211
Find similar
Southwest
Feb 3
SEA9:55 amSeattle/Tacoma Intl
9h 00m
1 stop
IAD9:55 pmWashington, D.C. Dulles Intl
Feb 10
IAD9:05 amWashington, D.C. Dulles Intl
17h 00m
2 stops
SEA11:05 pmSeattle/Tacoma Intl
$221
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 January 6, 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

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 1/30

8:30 am-4:26 pm

Nonstop4h 56m

Washington, D.C. Dulles Intl

Tue 2/3

6:04 pm-9:08 pm

Nonstop6h 04m

$199

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 2/5

5:15 am-4:00 pm

1 stop7h 45m

Washington, D.C. Dulles Intl

Mon 2/9

5:40 pm-10:50 pm

1 stop8h 10m

$202

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 2/26

12:43 pm-11:21 pm

1 stop7h 38m

Washington, D.C. Dulles Intl

Sun 3/1

5:55 pm-8:56 pm

Nonstop6h 01m

$205

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 1/30

8:35 am-9:17 pm

1 stop9h 42m

Washington, D.C. Dulles Intl

Tue 2/3

1:08 pm-7:04 pm

1 stop8h 56m

$208

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Mon 2/23

9:45 pm-5:40 am

Nonstop4h 55m

Washington, D.C. Dulles Intl

Tue 3/3

7:05 am-10:05 am

Nonstop6h 00m

$209

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 1/30

5:15 am-4:50 pm

1 stop8h 35m

Washington, D.C. Dulles Intl

Mon 2/2

4:30 pm-11:05 pm

1 stop9h 35m

$211

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 2/14

12:42 pm-11:21 pm

1 stop7h 39m

Washington, D.C. Dulles Intl

Thu 3/12

5:55 pm-8:56 pm

Nonstop6h 01m

$215

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Tue 3/31

3:55 pm-11:49 pm

Nonstop4h 54m

Washington, D.C. Dulles Intl

Tue 4/7

7:00 am-10:03 am

Nonstop6h 03m

$218

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 2/19

8:17 am-4:19 pm

Nonstop5h 02m

Washington, D.C. Dulles Intl

Tue 2/24

3:58 pm-9:12 pm

1 stop8h 14m

$219

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 1/29

12:45 pm-11:12 pm

1 stop7h 27m

Washington, D.C. Dulles Intl

Wed 2/4

1:08 pm-7:04 pm

1 stop8h 56m

$220

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 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 $437. 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 $337 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 $533 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 $422 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 $267 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.

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

As of January 2026, prices for Seattle to Washington, D.C. Dulles Intl Airport flights are approximately 7% 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

$183

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 $183. The best round-trip flight deal from Seattle to Washington, D.C. Dulles Intl Airport found on momondo in the last 72 hours is $340.
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
2,825 reviews
Search Hawaiian Airlines flights
DeltaPriceFrom $184Free CancellationRating
7.9
8,017 reviews
Search Delta flights
FrontierPriceFrom $188Free CancellationRating
5.7
3,064 reviews
Search Frontier flights
United AirlinesPriceFrom $257Free CancellationRating
7.4
9,134 reviews
Search United Airlines flights
Alaska AirlinesPriceFrom $277Free CancellationRating
8.0
11,650 reviews
Search Alaska Airlines flights
American AirlinesPriceFrom $336Free CancellationRating
7.2
11,083 reviews
Search American Airlines flights

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

    Across 1 Alaska Airlines flight from Seattle to Washington, D.C. Dulles Intl Airport this week, the average price was $426, with the best Alaska Airlines deals starting from $277 round-trip. 11,648 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 $184 round-trip, depending on your selected dates, with average Delta deals seen on momondo around $366. Delta operates 7 flights to Washington, D.C. Dulles Intl Airport from Seattle in an average week. Users have rated it 7.9/10 across 8,018 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
Tysons
Laurel
Colonial Beach
Silver Spring
Towson
Fredericksburg
Rockville
Gaithersburg
Harpers Ferry
Manassas
Sterling
Fairfax
Springfield

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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