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$132+ 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 1/18. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
Oct 19 — Oct 261
Sun 10/19
Sun 10/26
1 adult, Economy
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Cheapflights Tip: The best prices from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl are usually found in February or January, booked 43 days in advance, depart on a Tuesday or Wednesday and return on a Thursday

Cheap 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 September 19, 2025.

Round-trip from

$239
(KAYAK)

One-way from

$132
(Trip.com)

Popular in

December

Cheapest in

February

Average price

$377

Good round-trip deal

$334 or less

Good one-way deal

$189 or less
From Washington, D.C. Dulles Intl to Seattle/Tacoma Intl
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One-way flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 0% potential increase in price ($3 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($8 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Price to beat on a round-trip flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl.
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Price to beat on a one-way flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl.
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Find 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 September 19, 2025.

This KAYAK deal was found by Cheapflights users on 9/18. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/176:25 amIAD - SEA
Nonstop5h 43mAlaska Airlines
Thu 10/234:20 pmSEA - IAD
Nonstop5h 03mAlaska Airlines
Deal found 9/18$239
This Alaska Airlines deal was found by Cheapflights users on 9/17. 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.
Wed 12/107:35 amIAD - SEA
Nonstop6h 01mAlaska Airlines
Sun 12/1410:20 pmSEA - IAD
Nonstop4h 55mAlaska Airlines
Deal found 9/17$243
This KAYAK deal was found by Cheapflights users on 9/16. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/76:25 amIAD - SEA
Nonstop5h 43mAlaska Airlines
Wed 10/84:20 pmSEA - IAD
Nonstop5h 03mAlaska Airlines
Deal found 9/16$245
This United Airlines deal was found by Cheapflights users on 9/16. 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.
Thu 10/91:05 pmIAD - SEA
Nonstop5h 47mUnited Airlines
Tue 10/147:37 pmSEA - IAD
1 stop8h 25mUnited Airlines
Deal found 9/16$247
This Southwest deal was found by Cheapflights users on 9/16. 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.
Tue 10/287:40 amIAD - SEA
2 stops18h 15mSouthwest
Wed 10/295:50 amSEA - IAD
1 stop7h 10mSouthwest
Deal found 9/16$248
This Trip.com deal was found by Cheapflights users on 9/18. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/116:25 amIAD - SEA
Nonstop5h 43mHawaiian Airlines
Fri 10/174:20 pmSEA - IAD
Nonstop5h 03mHawaiian Airlines
Deal found 9/18$249
This Cheapflightsfares deal was found by Cheapflights users on 9/17. 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.
Wed 10/158:53 amIAD - SEA
Nonstop5h 45mAlaska Airlines
Wed 10/224:20 pmSEA - IAD
Nonstop5h 03mAlaska Airlines
Deal found 9/17$252
This Trip.com deal was found by Cheapflights users on 9/17. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/86:25 amIAD - SEA
Nonstop5h 43mAlaska Airlines
Wed 10/154:20 pmSEA - IAD
Nonstop5h 03mAlaska Airlines
Deal found 9/17$253
This Delta deal was found by Cheapflights users on 9/18. 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.
Wed 10/297:35 amIAD - SEA
Nonstop5h 53mDelta
Thu 11/64:48 pmSEA - IAD
Nonstop4h 52mDelta
Deal found 9/18$257
This SmartFares deal was found by Cheapflights users on 9/18. 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 SmartFares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/27:43 amIAD - SEA
Nonstop5h 52mAlaska Airlines
Sun 11/910:29 pmSEA - IAD
Nonstop4h 54mAlaska Airlines
Deal found 9/18$258
This KAYAK deal was found by Cheapflights users on 9/18. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/206:25 amIAD - SEA
Nonstop5h 43mAlaska Airlines
Mon 10/2710:29 pmSEA - IAD
Nonstop4h 54mAlaska Airlines
Deal found 9/18$259

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 September 19, 2025.
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

Dulles Intl

Fly to

Seattle

Route

Depart

Return

Price

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 11/18

7:15 am-10:19 am

Nonstop6h 04m

Seattle/Tacoma Intl

Tue 11/25

4:59 pm-12:54 am

Nonstop4h 55m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 11/14

7:43 am-10:35 am

Nonstop5h 52m

Seattle/Tacoma Intl

Sun 11/16

10:29 pm-6:23 am

Nonstop4h 54m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 10/15

5:55 pm-8:44 pm

Nonstop5h 49m

Seattle/Tacoma Intl

Wed 10/22

8:00 am-4:09 pm

Nonstop5h 09m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 12/5

7:15 am-10:12 am

Nonstop5h 57m

Seattle/Tacoma Intl

Mon 12/8

4:30 pm-12:26 am

Nonstop4h 56m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 11/18

6:13 pm-9:12 pm

Nonstop5h 59m

Seattle/Tacoma Intl

Wed 11/26

10:24 pm-6:18 am

Nonstop4h 54m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 11/4

5:55 pm-8:54 pm

Nonstop5h 59m

Seattle/Tacoma Intl

Sat 11/8

8:00 am-4:07 pm

Nonstop5h 07m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 11/1

7:35 am-10:28 am

Nonstop5h 53m

Seattle/Tacoma Intl

Thu 11/6

4:48 pm-12:40 am

Nonstop4h 52m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 10/31

5:55 pm-8:54 pm

Nonstop5h 59m

Seattle/Tacoma Intl

Mon 11/3

8:00 am-4:07 pm

Nonstop5h 07m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 10/23

8:53 am-11:38 am

Nonstop5h 45m

Seattle/Tacoma Intl

Mon 10/27

10:29 pm-6:23 am

Nonstop4h 54m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 12/3

7:15 am-10:12 am

Nonstop5h 57m

Seattle/Tacoma Intl

Thu 12/4

4:30 pm-12:26 am

Nonstop4h 56m

$257

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/15

Showing 1-10 of 22 results
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The best insider tips for Washington, D.C. Dulles Intl Airport to Seattle 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 Washington, D.C. Dulles Intl Airport to Seattle trip
Airports
IAD

For a smooth check-in at IAD, locate your airline’s counter by walking around the first row if not visible initially.

Read more about IADby Ramsey Qubein
SEA

Use the Link light rail from SEA to downtown Seattle for an affordable, 40-minute ride with ample luggage space.

Read more about SEAby Brandon Schultz
Our travel experts
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 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?

Use this chart to determine the optimal time to book a round-trip flight from Dulles Intl to Seattle. Price data was last updated on September 12, 2025.

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 36 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 $238). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of $387). 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 September 19, 2025.

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 morning tend to be the most expensive. A flight in the evening could potentially save you up to 17% 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 September 14, 2025.

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

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 September 19, 2025.
See what other customers who have flown with Alaska Airlines, Delta, and Hawaiian 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.
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
Delta
8.0
Very good
7,964 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
Hawaiian Airlines
7.8
Good
2,732 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
United Airlines
7.4
Good
8,926 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Overall

8.0

Crew

8.5

Boarding

8.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Aug 2025

MFR - SEA

Great smooth flight. Was hour and half late though. Don't know why

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 22 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 52m. Fly via Delta or Alaska 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 $111. Other airlines that can offer you cheap pricing are Hawaiian Airlines, from $157, and Delta, from $182. Frontier is currently priced 72% below the average price you’ll pay for this route.

  • 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 Japan Airlines (97%), China Eastern (90%) and Delta (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 $138. On average you can expect to pay $849. The most popular route, (Washington, D.C. Dulles Intl - Seattle/Tacoma Intl), can usually be booked for $184.

  • 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 $238). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of $387). 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
Tukwila
Tacoma
Lakewood
Ocean Shores
Lynnwood
Edmonds
Leavenworth
Renton
Lacey
Olympia
Kent
Federal Way
Cle Elum
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Shoreline

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Alternative routes for Dulles Intl to Seattle

See prices for flight routes from nearby airports that may be better suited for you.
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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 September 19, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$111Average$257FlexibilityNo cancel feeOn-time62%
Hawaiian AirlinesCheapest$157Average$389FlexibilityNo cancel feeOn-time85%
DeltaCheapest$182Average$388FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$269Average$428FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$281Average$460FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$321Average$497FlexibilityNo cancel feeOn-time71%

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