Seattle

$173+ Cheap flights from Dulles Intl (IAD) to Seattle (SEA)

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 8/9. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
Jul 14 — Jul 211
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Find cheap flights from Dulles Intl to Seattle with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

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Cheapflights Tip: The best prices from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl are usually found in January or February, booked 53 days in advance, depart on a Tuesday or Wednesday and return on a Wednesday

Cheap flight deals from Dulles Intl to Seattle

Cheapest flights from Dulles Intl to Seattle
Explore the most affordable flight options available from Dulles Intl to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 14, 2026.

This CheapOair deal was found by Cheapflights users on 6/12. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/19:55 am
IAD
-
SEA
1 stop27h 40m
Frontier
Fri 7/108:53 pm
SEA
-
IAD
1 stop8h 27m
Frontier
Deal found 6/12$322
This Expedia deal was found by Cheapflights users on 6/10. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/129:30 am
IAD
-
SEA
Nonstop5h 46m
Multiple Airlines
Wed 8/198:13 pm
SEA
-
IAD
1 stop8h 37m
Multiple Airlines
Deal found 6/10$323
This Booking.com deal was found by Cheapflights users on 6/10. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/209:50 am
IAD
-
SEA
1 stop27h 49m
Multiple Airlines
Tue 7/219:04 pm
SEA
-
IAD
1 stop18h 41m
Multiple Airlines
Deal found 6/10$324
This Alaska Airlines deal was found by Cheapflights users on 6/10. 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.
Thu 8/277:00 am
IAD
-
SEA
Nonstop5h 37m
Alaska Airlines
Mon 8/317:50 pm
SEA
-
IAD
1 stop19h 24m
Alaska Airlines
Deal found 6/10$325
This American Airlines deal was found by Cheapflights users on 6/10. 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.
Thu 8/272:53 pm
IAD
-
SEA
1 stop10h 28m
American Airlines
Sat 9/55:00 am
SEA
-
IAD
1 stop10h 27m
American Airlines
Deal found 6/10$326
This Kiwi.com deal was found by Cheapflights users on 6/11. 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 7/259:30 am
IAD
-
SEA
1 stop28h 09m
Frontier
Tue 7/288:13 pm
SEA
-
IAD
1 stop9h 07m
Frontier
Deal found 6/11$327
This Kiwi.com deal was found by Cheapflights users on 6/11. 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.
Mon 7/279:50 am
IAD
-
SEA
2 stops26h 27m
Frontier
Tue 7/288:13 pm
SEA
-
IAD
1 stop9h 07m
Frontier
Deal found 6/11$328
This Booking.com deal was found by Cheapflights users on 6/11. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/149:50 am
IAD
-
SEA
1 stop27h 49m
Multiple Airlines
Wed 7/2210:43 pm
SEA
-
IAD
Nonstop4h 56m
Multiple Airlines
Deal found 6/11$329
This United Airlines deal was found by Cheapflights users on 6/12. 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.
Tue 8/45:55 pm
IAD
-
SEA
Nonstop5h 51m
United Airlines
Wed 8/126:15 pm
SEA
-
IAD
1 stop8h 10m
United Airlines
Deal found 6/12$330
This Expedia deal was found by Cheapflights users on 6/9. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/36:14 pm
IAD
-
SEA
Nonstop5h 55m
Multiple Airlines
Thu 8/68:53 pm
SEA
-
IAD
1 stop8h 27m
Multiple Airlines
Deal found 6/9$331
This United Airlines deal was found by Cheapflights users on 6/9. 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.
Sun 8/25:55 pm
IAD
-
SEA
Nonstop5h 51m
United Airlines
Thu 8/136:15 pm
SEA
-
IAD
1 stop8h 10m
United Airlines
Deal found 6/9$332
This United Airlines deal was found by Cheapflights users on 6/11. 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.
Wed 8/265:33 pm
IAD
-
SEA
Nonstop5h 45m
United Airlines
Sun 8/3011:04 pm
SEA
-
IAD
Nonstop5h 03m
United Airlines
Deal found 6/11$334

Find flight deals from Dulles Intl to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Dulles Intl (IAD) to Seattle (SEA). 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 June 14, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$322
(CheapOair)

One-way from

$173
(United Airlines)

Popular in

June

Cheapest in

January

Average price

$546

Good round-trip deal

$385 or less

Good one-way deal

$244 or less
Provider with most accurate pricing for Washington, D.C. Dulles Intl-Seattle/Tacoma Intl flight deals.
Provider most trusted by Cheapflights users for Washington, D.C. Dulles Intl-Seattle/Tacoma Intl flights.
From Washington, D.C. Dulles Intl to Seattle/Tacoma Intl
One-way flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl
Highest demand for flights based on searches. 20% potential increase in price ($99 potential increase over avg. RT price).
Cheapest flight prices on average. 3% potential price decrease ($14 potential savings vs. average RT price).
Average for round-trip flights in June 2026
Price to beat on a round-trip flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl.
Price to beat on a one-way flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl.

Cheapflights Fare Finder

 
Customize your flight search to find flights from Dulles Intl 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, Cheapflights users made 2,558,603 searches. Data last updated June 14, 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

Cheapest round-trip

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 8/15

6:03 am-8:48 am

Nonstop5h 45m

Seattle/Tacoma Intl

Mon 8/24

9:35 pm-5:40 am

Nonstop5h 05m

$340

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 8/6

7:53 pm-9:19 am

1 stop16h 26m

Seattle/Tacoma Intl

Fri 8/14

10:43 pm-6:39 am

Nonstop4h 56m

$345

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 7/3

5:55 pm-8:46 pm

Nonstop5h 51m

Seattle/Tacoma Intl

Wed 7/8

8:15 am-4:24 pm

Nonstop5h 09m

$360

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 8/4

5:55 pm-8:46 pm

Nonstop5h 51m

Seattle/Tacoma Intl

Wed 8/12

1:57 pm-12:44 am

1 stop7h 47m

$369

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 7/22

6:14 pm-9:09 pm

Nonstop5h 55m

Seattle/Tacoma Intl

Thu 7/30

4:01 pm-11:59 pm

Nonstop4h 58m

$380

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 8/11

7:10 am-9:55 am

Nonstop5h 45m

Seattle/Tacoma Intl

Wed 8/19

5:30 am-4:38 pm

1 stop8h 08m

$385

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sun 7/19

6:03 am-8:48 am

Nonstop5h 45m

Seattle/Tacoma Intl

Wed 7/29

6:21 am-6:45 pm

1 stop9h 24m

$390

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 8/4

5:55 pm-8:46 pm

Nonstop5h 51m

Seattle/Tacoma Intl

Tue 8/18

1:57 pm-12:44 am

1 stop7h 47m

$401
Quickest round-trip

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 8/3

9:30 am-12:16 pm

Nonstop5h 46m

Seattle/Tacoma Intl

Thu 8/13

10:43 pm-6:39 am

Nonstop4h 56m

$425

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 8/25

8:31 am-8:43 pm

2 stops15h 12m

Seattle/Tacoma Intl

Wed 8/26

11:00 pm-11:52 am

1 stop9h 52m

$430

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 24 resultsSorted by cheapest first
1
2
3

Compare providers for flights from Dulles Intl to Seattle

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Dulles Intl to Seattle in June.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
CheapTicketsDealPrice Accuracy1 starTrust Score*3 stars
CheapfaremartPrice Accuracy-Trust Score*1 star

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Washington, D.C. Dulles Intl Airport-Seattle flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Washington, D.C. Dulles Intl Airport-Seattle flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Washington, D.C. Dulles Intl Airport-Seattle flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Washington, D.C. Dulles Intl Airport-Seattle flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Washington, D.C. Dulles Intl Airport-Seattle flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Dulles Intl to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Dulles Intl 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 Washington, D.C. Dulles Intl Airport to Seattle

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

The price you pay for your flight from Washington, D.C. Dulles Intl Airport to Seattle may vary depending on when you book. For the best chance of a lower fare, look to book 52 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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

Currently, January is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Seattle (average of $231). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of $546). 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 IAD to SEA?

Find hourly flight availability from Dulles Intl to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 14, 2026.

One of the essential ways to save on airfare from Washington, D.C. Dulles Intl Airport to Seattle is to remain as flexible as possible. Flights that are in the evening tend to be the most expensive. A flight at noon could potentially save you up to 16% on airfare.

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

Use this chart to determine the cheapest time to fly round-trip from Dulles Intl to Seattle. Price data was last updated on June 13, 2026.

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

How much does it cost to fly round-trip from Washington, D.C. Dulles Intl Airport to Seattle?

The best insider tips for Washington, D.C. Dulles Intl Airport to Seattle flights

AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Washington, D.C. Dulles Intl Airport to Seattle trip
Our travel experts
Ramsey Qubein

Ramsey Qubein

Expert on IAD

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.

Brandon Schultz

Brandon Schultz

Expert on SEA

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.

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated June 14, 2026.
See what other customers who have flown with Alaska Airlines,Delta, andHawaiian Airlines from Washington, D.C. Dulles Intl Airport to Seattle have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.

Food

7.0

Comfort

7.8

Entertainment

7.0

Crew

8.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Jun 2026

RDU - SEA

There was almost a 2 hour delay after arriving before our next flight. Also my husband needed a wheelchair and it seemed hard to get help.

Food

7.0

Comfort

7.8

Entertainment

7.0

Crew

8.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Jun 2026

RDU - SEA

There was almost a 2 hour delay after arriving before our next flight. Also my husband needed a wheelchair and it seemed hard to get help.

Food

7.0

Comfort

7.8

Entertainment

7.0

Crew

8.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Jun 2026

RDU - SEA

There was almost a 2 hour delay after arriving before our next flight. Also my husband needed a wheelchair and it seemed hard to get help.

Food

7.0

Comfort

7.8

Entertainment

7.0

Crew

8.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Jun 2026

RDU - SEA

There was almost a 2 hour delay after arriving before our next flight. Also my husband needed a wheelchair and it seemed hard to get help.

Food

7.0

Comfort

7.8

Entertainment

7.0

Crew

8.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Jun 2026

RDU - SEA

There was almost a 2 hour delay after arriving before our next flight. Also my husband needed a wheelchair and it seemed hard to get help.

Food

7.0

Comfort

7.8

Entertainment

7.0

Crew

8.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Jun 2026

RDU - SEA

There was almost a 2 hour delay after arriving before our next flight. Also my husband needed a wheelchair and it seemed hard to get help.

Related info for your journey

Find useful and relevant information for your journey from Dulles Intl to Seattle. 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 into for flights to Seattle from Washington, D.C. Dulles Intl?

    Seattle/Tacoma Intl (SEA), located 11.4 mi from the city center, is the airport you fly into when you book flights from Washington, D.C. Dulles Intl to Seattle. 6 airlines have flights to Seattle/Tacoma Intl from Washington, D.C. Dulles Intl on a regular basis. Booking flights from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl should not be difficult; the airport handles an average of 21 inbound flights from Washington, D.C. Dulles Intl per day.

  • How long is the flight from Washington, D.C. Dulles Intl Airport to Seattle?

    There are many flights that can get you from Washington, D.C. Dulles Intl Airport to Seattle in 5h 45m. Fly via Alaska Airlines or United Airlines to get the fastest option. Airlines will cover a distance of 2299 mi. Generally, flights for this route are nonstop.

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

    Cheapflights users have booked flights from Washington, D.C. Dulles Intl Airport to Seattle round-trip from $138. Other airlines that can offer you cheap pricing are Delta, from $144, and Frontier, from $145. Hawaiian Airlines is currently priced 64% below the average price you’ll pay for this route.

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

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $116. Alaska Airlines flights start at $119 while deals on Delta start at $119 one-way.

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

    The top 3 most reliable airlines when flying from Washington, D.C. Dulles Intl Airport to Seattle are Finnair (100%), Japan Airlines (93%) and China Eastern (90%).

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

    The cheapest flight price from Washington, D.C. Dulles Intl Airport to Seattle is $147. On average you can expect to pay $1,091. The most popular route, (Washington, D.C. Dulles Intl - Seattle/Tacoma Intl), can usually be booked for $255.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Dulles Intl to Seattle 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 Washington, D.C. Dulles Intl Airport to Seattle?

    Currently, January is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Seattle (average of $231). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of $546). 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 Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Tacoma
Lacey
Ocean Shores
Leavenworth
Olympia
Edmonds
Snoqualmie
Tumwater
Tukwila
Puyallup
Kent
Lynnwood
Renton
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Issaquah
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Shoreline

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Top 6 airlines flying from Dulles Intl to Seattle

Discover the top 6 airlines that operate flights from Dulles Intl to Seattle. 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 June 14, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$121Average$307FlexibilityNo cancel feeOn-time62%
Hawaiian AirlinesCheapest$138Average$317FlexibilityNo cancel feeOn-time85%
DeltaCheapest$144Average$358FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$199Average$437FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$221Average$434FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$337Average$527FlexibilityNo cancel feeOn-time71%

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