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$143+ 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 8/22. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
ago. 2 — ago. 91
sáb. 8/2
sáb. 8/9
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 58 days in advance, depart on a Tuesday or Wednesday and return on a Tuesday

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 julio 28, 2025.

Round-trip from

$260
(SmartFares)

One-way from

$143
(Cheapflightsfares)

Popular in

December

Cheapest in

February

Average price

$457

Good round-trip deal

$363 or less

Good one-way deal

$219 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. 2% potential increase in price ($10 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($10 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 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 julio 28, 2025.

This SmartFares deal was found by Cheapflights users on 7/26. 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.
mar. 9/96:09 pmIAD - SEA
Nonstop5h 47mHawaiian Airlines
mar. 9/1611:30 pmSEA - IAD
Nonstop5h 03mHawaiian Airlines
Deal found 7/26$260
This SmartFares deal was found by Cheapflights users on 7/26. 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.
mar. 9/99:00 amIAD - SEA
Nonstop5h 43mAlaska Airlines
mar. 9/1611:30 pmSEA - IAD
Nonstop5h 03mAlaska Airlines
Deal found 7/26$263
This Delta deal was found by Cheapflights users on 7/26. 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.
lun. 8/187:35 amIAD - SEA
Nonstop5h 45mDelta
mar. 8/269:55 pmSEA - IAD
Nonstop5h 00mDelta
Deal found 7/26$287
This American Airlines deal was found by Cheapflights users on 7/26. 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.
mar. 9/911:47 amIAD - SEA
1 stop8h 06mAmerican Airlines
mar. 9/165:26 amSEA - IAD
1 stop8h 24mAmerican Airlines
Deal found 7/26$294
This Frontier deal was found by Cheapflights users on 7/27. 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.
jue. 8/147:30 amIAD - SEA
1 stop9h 36mFrontier
lun. 8/183:11 pmSEA - IAD
1 stop12h 23mFrontier
Deal found 7/27$298
This Southwest deal was found by Cheapflights users on 7/28. 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.
mar. 8/262:25 pmIAD - SEA
1 stop9h 30mSouthwest
mié. 8/277:00 amSEA - IAD
2 stops12h 05mSouthwest
Deal found 7/28$302
This Sun Country Air deal was found by Cheapflights users on 7/26. 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 Sun Country Air is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 10/36:30 pmIAD - SEA
1 stop25h 31mSun Country Air
sáb. 10/116:28 pmSEA - IAD
1 stop14h 10mSun Country Air
Deal found 7/26$315
This United Airlines deal was found by Cheapflights users on 7/28. 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.
mar. 11/115:55 pmIAD - SEA
Nonstop5h 59mUnited Airlines
dom. 11/166:00 amSEA - IAD
1 stop7h 25mUnited Airlines
Deal found 7/28$324

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 julio 28, 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

mar. 9/9

6:09 pm-8:56 pm

Nonstop5h 47m

Seattle/Tacoma Intl

mar. 9/16

11:30 pm-7:33 am

Nonstop5h 03m

$260

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

mar. 9/9

9:00 am-11:43 am

Nonstop5h 43m

Seattle/Tacoma Intl

mar. 9/16

11:30 pm-7:33 am

Nonstop5h 03m

$263

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

mar. 9/9

11:47 am-4:53 pm

1 stop8h 06m

Seattle/Tacoma Intl

mar. 9/16

5:26 am-4:50 pm

1 stop8h 24m

$294

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

jue. 8/14

7:30 am-2:06 pm

1 stop9h 36m

Seattle/Tacoma Intl

lun. 8/18

3:11 pm-6:34 am

1 stop12h 23m

$298

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

mar. 8/26

2:25 pm-8:55 pm

1 stop9h 30m

Seattle/Tacoma Intl

mié. 8/27

7:00 am-10:05 pm

2 stops12h 05m

$302

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

vie. 10/3

6:30 pm-5:01 pm

1 stop25h 31m

Seattle/Tacoma Intl

sáb. 10/11

6:28 pm-11:38 am

1 stop14h 10m

$315

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

mar. 9/9

12:13 pm-11:15 pm

1 stop14h 02m

Seattle/Tacoma Intl

sáb. 9/20

9:55 pm-6:01 am

Nonstop5h 06m

$316

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

jue. 10/9

5:55 pm-8:44 pm

Nonstop5h 49m

Seattle/Tacoma Intl

lun. 10/13

7:37 pm-7:02 am

1 stop8h 25m

$333

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

vie. 8/22

8:00 am-2:40 pm

1 stop9h 40m

$143

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

jue. 10/16

11:52 am-5:25 pm

1 stop8h 33m

$145

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/28

Showing 1-10 of 17 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 July 25, 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 58 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 $389). 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 julio 28, 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 18% 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 July 20, 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.

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

Explore weekly flight availability from Dulles Intl to Seattle. 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 julio 28, 2025.

The most flights from IAD to SEA are scheduled on a Monday (30 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (27 on average).

What’s the top layover airport for flights from Washington, D.C. Dulles Intl Airport to Seattle?

Share of 1-stop round-trip flights from Washington, D.C. Dulles Intl Airport to Seattle chosen by Cheapflights users in the past 12 months, using the same layover each way.

Las Vegas (LAS) – chosen by Cheapflights users on 67% of 1-stop itineraries from Washington, D.C. Dulles Intl Airport to Seattle on Cheapflights.

What’s the cheapest layover airport for flights from Washington, D.C. Dulles Intl Airport to Seattle?

Average round-trip fare for 1-stop flights from Washington, D.C. Dulles Intl Airport to Seattle, chosen by Cheapflights users in the past 12 months, with the same layover each way.

Las Vegas (LAS) is the most affordable 1-stop option, with an average round-trip price of $218.

What’s the fastest layover option from Washington, D.C. Dulles Intl Airport to Seattle?

Shortest average travel time for 1-stop one-way flights from Washington, D.C. Dulles Intl Airport to Seattle, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

Flights via Denver (DEN) have the shortest average one-way travel time for 1-stop routes: 5h 36m.

Which airport typically offers the quickest layover for flights from Washington, D.C. Dulles Intl Airport to Seattle?

Average layover duration for 1-stop one-way flights from Washington, D.C. Dulles Intl Airport to Seattle, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Denver (DEN) offer the fastest connection on this route, with an average layover time of 2h 04m.

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 julio 28, 2025.
See what other customers who have flown with Alaska Airlines, Southwest, and Delta 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

Boarding

8.1

Food

7.1

Comfort

7.8

Crew

8.5

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Food

7.1

Comfort

7.8

Crew

8.5

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Southwest
8.0
Very good
4,237 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Food

7.1

Comfort

7.8

Crew

8.5

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Delta
8.0
Very good
7,971 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Food

7.1

Comfort

7.8

Crew

8.5

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Hawaiian Airlines
7.8
Good
2,604 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Food

7.1

Comfort

7.8

Crew

8.5

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
United Airlines
7.4
Good
8,893 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Food

7.1

Comfort

7.8

Crew

8.5

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.

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. 7 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 28 inbound flights from Washington, D.C. Dulles Intl per day.

  • 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 $260. Other airlines that can offer you cheap pricing are Alaska Airlines, from $263, and American Airlines, from $294. Hawaiian Airlines is currently priced 36% 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 $143. Sun Country Air flights start at $145 while deals on Alaska Airlines start at $148 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 Japan Airlines (97%), China Eastern (82%) and Delta (82%).

  • 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 $148. On average you can expect to pay $1,117. The most popular route, (Washington, D.C. Dulles Intl - Seattle/Tacoma Intl), can usually be booked for $263.

  • 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 $389). 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
Ocean Shores
Lakewood
Lynnwood
Lacey
Leavenworth
Renton
Olympia
Puyallup
Kent
Cle Elum
Chehalis
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Issaquah
Aberdeen
Shoreline
Federal Way
Shelton

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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 7 airlines flying from Dulles Intl to Seattle

Discover the top 7 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 julio 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$111Average$252FlexibilityNo cancel feeOn-time62%
Sun Country AirCheapest$144Average$370FlexibilityNo cancel feeOn-time83%
Hawaiian AirlinesCheapest$168Average$388FlexibilityNo cancel feeOn-time85%
DeltaCheapest$208Average$380FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$262Average$426FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$283Average$466FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$297Average$522FlexibilityNo cancel feeOn-time71%

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