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Dulles Intl

$147+ Cheap flights from Seattle (SEA) to Dulles Intl (IAD)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 8/27. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — IAD
Aug 5 — Aug 121
Tue 8/5
Tue 8/12
1 adult, Economy
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Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl are usually found in September or February, booked 52 days in advance, depart on a Tuesday or Thursday and return on a Tuesday

Cheap flight deals from Seattle to Dulles Intl

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Dulles Intl (IAD). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated July 31, 2025.

Round-trip from

$257
(Alaska Airlines)

One-way from

$147
(Expedia)

Popular in

December

Cheapest in

September

Average price

$429

Good round-trip deal

$332 or less

Good one-way deal

$213 or less
From Seattle/Tacoma Intl to Washington, D.C. Dulles Intl
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One-way flight from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl
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Highest demand for flights based on searches. 6% potential increase in price ($27 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($11 potential savings vs. average RT price).
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Average for round-trip flights in July 2025
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl.
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Price to beat on a one-way flight from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl.
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Find flight deals from Seattle to Dulles Intl

Cheapest flights from Seattle to Dulles Intl
Explore the most affordable flight options available from Seattle to Dulles Intl. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 31, 2025.

This Delta deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/309:55 pmSEA - IAD
Nonstop5h 00mDelta
Sat 9/67:35 amIAD - SEA
Nonstop5h 45mDelta
Deal found 7/31$257
This Kiwi.com deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/304:20 pmSEA - IAD
Nonstop5h 00mHawaiian Airlines
Sat 9/67:00 amIAD - SEA
Nonstop5h 40mHawaiian Airlines
Deal found 7/29$263
This United Airlines deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/135:35 pmSEA - IAD
1 stop8h 49mUnited Airlines
Sat 9/201:05 pmIAD - SEA
Nonstop5h 46mUnited Airlines
Deal found 7/31$267
This Alaska Airlines deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2011:30 pmSEA - IAD
Nonstop5h 03mAlaska Airlines
Sun 9/219:00 amIAD - SEA
Nonstop5h 43mAlaska Airlines
Deal found 7/31$271
This Frontier deal was found by Cheapflights users on 7/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/153:11 pmSEA - IAD
1 stop12h 23mFrontier
Thu 8/218:00 amIAD - SEA
1 stop9h 40mFrontier
Deal found 7/30$298
This Cheapflightsfares deal was found by Cheapflights users on 7/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/306:22 pmSEA - IAD
1 stop13h 36mSun Country Air
Sun 11/212:50 pmIAD - SEA
1 stop7h 25mSun Country Air
Deal found 7/30$299
This Southwest deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/65:00 amSEA - IAD
1 stop7h 00mSouthwest
Tue 9/95:45 amIAD - SEA
2 stops12h 25mSouthwest
Deal found 7/29$302
This American Airlines deal was found by Cheapflights users on 7/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/135:26 amSEA - IAD
1 stop8h 21mAmerican Airlines
Sat 9/202:21 pmIAD - SEA
1 stop8h 44mAmerican Airlines
Deal found 7/30$305

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to Dulles Intl 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, Cheapflights users made 2,558,603 searches. Data last updated July 31, 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

Seattle

Fly to

Dulles Intl

Route

Depart

Return

Price

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 8/30

11:30 pm-7:32 am

Nonstop5h 02m

Washington, D.C. Dulles Intl

Wed 9/3

6:09 pm-8:56 pm

Nonstop5h 47m

$257

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 8/30

4:20 pm-12:20 am

Nonstop5h 00m

Washington, D.C. Dulles Intl

Sat 9/6

7:00 am-9:40 am

Nonstop5h 40m

$263

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 9/13

5:35 pm-5:24 am

1 stop8h 49m

Washington, D.C. Dulles Intl

Sat 9/20

1:05 pm-3:51 pm

Nonstop5h 46m

$267

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 8/15

3:11 pm-6:34 am

1 stop12h 23m

Washington, D.C. Dulles Intl

Mon 8/18

7:30 am-2:06 pm

1 stop9h 36m

$298

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 8/27

6:34 pm-11:47 am

1 stop14h 13m

Washington, D.C. Dulles Intl

Sun 8/31

11:42 am-10:43 pm

1 stop14h 01m

$299

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 9/6

5:00 am-3:00 pm

1 stop7h 00m

Washington, D.C. Dulles Intl

Tue 9/9

5:45 am-3:10 pm

2 stops12h 25m

$302

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 9/13

5:26 am-4:47 pm

1 stop8h 21m

Washington, D.C. Dulles Intl

Sat 9/20

2:21 pm-8:05 pm

1 stop8h 44m

$305

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 8/28

9:55 pm-5:55 am

Nonstop5h 00m

Washington, D.C. Dulles Intl

Tue 9/2

8:23 pm-8:14 pm

1 stop26h 51m

$326

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 8/27

11:30 pm-7:32 am

Nonstop5h 02m

$147

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 8/21

3:25 pm-6:30 am

1 stop12h 05m

$148

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/30

Showing 1-10 of 16 results
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The best insider tips for Seattle to Washington, D.C. Dulles Intl Airport flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your Seattle to Washington, D.C. Dulles Intl Airport trip
Airlines
Alaska Airlines

Saver Fare allows a carry-on bag, unlike many basic economy options.


Alaska Lounge offers fresh seasonal food and craft cocktails, surpassing many competitors.

Read more about Alaska Airlinesby Robert Schrader
United Airlines

Basic Economy allows a personal item only, no carry-on bags unless exceptions apply.


Polaris Business Class offers lie-flat seats and access to exclusive Polaris Lounges.

Read more about United Airlinesby Harriet Baskas
Airports
SEA

Plan to arrive at SEA at least two hours before your flight. Use SEA Spot Saver for advance security screening appointments.

Read more about SEAby Brandon Schultz
IAD

Use the Washington Metro Silver line for a cost-effective way to reach downtown from IAD in under 40 minutes.

Read more about IADby Ramsey Qubein
Our travel experts
Robert Schrader

Robert Schrader

Expert on Alaska Airlines

Robert Schrader

Robert Schrader

One of the web's original travel bloggers, Robert launched his first site Leave Your Daily Hell in 2009. Since then, he's expanded into destination niche sites (one each for Japan, Thailand and Taiwan), in addition to having written for the inflight magazines of Singapore Airlines and Korean Air. Overall, he's visited nearly 100 countries, and flies business as often as possible.

Read more
Harriet Baskas

Harriet Baskas

Expert on United Airlines

Harriet Baskas

Harriet Baskas

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Read more
Ramsey Qubein

Ramsey Qubein

Expert on IAD

Ramsey Qubein

Ramsey Qubein

An avid traveler and aviation expert who has visited 173 countries, all 50 states and seven continents, Ramsey Qubein flies nearly 400,000 miles a year. As a North Carolina-based freelance journalist for publications including Conde Nast Traveler, Forbes, USA Today and Bloomberg among others, he explores the latest trends in aviation, hospitality, cruises and business.

Read more
Brandon Schultz

Brandon Schultz

Expert on SEA

Brandon Schultz

Brandon Schultz

Brandon Schultz is an award-winning food and travel writer based in New York City. His work has appeared in Forbes, AAA, Thrillist, Travel + Leisure, and The Daily Meal, among many others, and he is the author of 6 books, including 3 cookbooks.

Read more

Best time to book a flight from Seattle to Dulles Intl

Have a flexible travel schedule? Discover the best time to fly to Dulles Intl from Seattle with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Washington, D.C. Dulles Intl Airport

How far ahead should I book a flight from Seattle to Washington, D.C. Dulles Intl Airport?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to Dulles Intl. Price data was last updated on July 25, 2025.

Booking 52 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to Washington, D.C. Dulles Intl Airport. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

What is the cheapest month to book a flight from Seattle to Washington, D.C. Dulles Intl Airport?

Currently, July is the cheapest month in which you can book a flight from Seattle to Washington, D.C. Dulles Intl Airport (average of $306). Flying from Seattle to Washington, D.C. Dulles Intl Airport in April is currently the most expensive (average of $337). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from SEA to IAD?

Find hourly flight availability from Seattle to Dulles Intl. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated July 31, 2025.

A simple way to save on the total cost of your ticket is to fly from Seattle to Washington, D.C. Dulles Intl Airport in the afternoon. If you’re flexible enough to do this you can expect to save up to 45% on your trip compared to booking a flight at noon.

What is the cheapest day to fly from Seattle to Washington, D.C. Dulles Intl Airport?

Use this chart to determine the cheapest time to fly round-trip from Seattle to Dulles Intl. Price data was last updated on July 27, 2025.

Travelers seeking maximum savings on their Seattle to Washington, D.C. Dulles Intl Airport flight should consider departing on Saturday afternoons when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Seattle to Washington, D.C. Dulles Intl Airport

Explore weekly flight availability from Seattle to Dulles Intl. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated July 31, 2025.

The most flights from SEA to IAD are scheduled on a Thursday (33 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (17 on average).

Reviews of airlines servicing Dulles Intl

Get insights into the airlines that provide service to Dulles Intl. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Dulles Intl. Reviews last updated July 31, 2025.
See what other customers who have flown with Alaska Airlines, Southwest, and Delta from Seattle to Washington, D.C. Dulles Intl Airport have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Food

7.1

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Food

7.1

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Southwest
8.0
Very good
4,246 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Food

7.1

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Delta
8.0
Very good
7,981 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Food

7.1

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Hawaiian Airlines
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Food

7.1

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
United Airlines
7.4
Good
8,900 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Food

7.1

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.

Related info for your journey

Find useful and relevant information for your journey from Seattle to Dulles Intl. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly from for flights from Seattle to Washington, D.C. Dulles Intl?

    If you book a flight to Washington, D.C. Dulles Intl from Seattle, you will be flying from Seattle/Tacoma Intl, which is the city’s only airport. Seattle/Tacoma Intl (SEA) is located 11.4 mi from the center of Seattle. There are 24 flights from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl per day from 5 different airlines.

  • What are the cheapest airlines flying from Seattle to Washington, D.C. Dulles Intl Airport round-trip?

    Alaska Airlines, at $257, was found to be the cheapest airline from Seattle to Washington, D.C. Dulles Intl Airport.Alternate airlines to your destination round-trip include Hawaiian Airlines and United Airlines. Alaska Airlines is 35% cheaper than the average price of flights available within the next 90 days to this destination.

  • What are the cheapest airlines to fly from Seattle to Washington, D.C. Dulles Intl Airport one-way?

    The cheapest airlines for a one-way flight from Seattle to Washington, D.C. Dulles Intl Airport are Alaska Airlines ($147), Delta ($149), and Sun Country Air ($153).

  • What are the most reliable airlines from Seattle to Washington, D.C. Dulles Intl Airport?

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Seattle to Washington, D.C. Dulles Intl Airport on time: Austrian Airlines (87%), Brussels Airlines (87%), Lufthansa (86%).

  • What are the cheapest flights from Seattle to Washington, D.C. Dulles Intl Airport?

    Looking at all options, your cheapest flight can be booked for $141. While the most popular route (Seattle/Tacoma Intl - Washington, D.C. Dulles Intl) can be booked for $257 on average our data indicates $1,059 when flying from Seattle to Washington, D.C. Dulles Intl Airport.

  • Can I find deals for flights from Seattle to Dulles Intl that include hotel bookings?

    Yes. In addition to deals on Seattle to Dulles Intl flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to Dulles Intl?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Dulles Intl.

  • Can I find deals for business class flights from Seattle to Dulles Intl?

    Yes. Cheapflights offers flight deals from Seattle to Dulles Intl by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to Washington, D.C. Dulles Intl Airport?

    Currently, July is the cheapest month in which you can book a flight from Seattle to Washington, D.C. Dulles Intl Airport (average of $306). Flying from Seattle to Washington, D.C. Dulles Intl Airport in April is currently the most expensive (average of $337). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near Washington, D.C. Dulles Intl Airport?

Book flights to Washington, D.C. Dulles Intl Airport if you plan to visit one of these locations
Woodbridge
Arlington
Alexandria
Tysons
Silver Spring
Fredericksburg
Gaithersburg
Towson
Linthicum Heights
Easton
Fairfax
Manassas
Falls Church
Waldorf
Laurel
Rockville
Oxon Hill
National Harbor
Dundalk
Bowie

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Seattle to Dulles Intl

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Seattle to Dulles Intl

Discover the top 5 airlines that operate flights from Seattle to Dulles Intl. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 31, 2025.
AirlineCheapestAverageFlexibilityOn-time
Hawaiian AirlinesCheapest$143Average$332FlexibilityNo cancel feeOn-time85%
DeltaCheapest$219Average$361FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$237Average$442FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$256Average$488FlexibilityNo cancel feeOn-time71%
Alaska AirlinesCheapest$258Average$416FlexibilityNo cancel feeOn-time75%

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