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$145+ 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 7/5. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
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 66 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 June 12, 2025.

Round-trip from

$267
(American Airlines)

One-way from

$145
(Cheapflightsfares)

Popular in

December

Cheapest in

February

Average price

$477

Good round-trip deal

$346 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. 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 June 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 June 12, 2025.

This American 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/291:06 pmIAD - SEA
1 stop10h 35mAmerican Airlines
Tue 8/59:41 pmSEA - IAD
1 stop9h 12mAmerican Airlines
Deal found 6/9$267
This FlightHub 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/187:30 amIAD - SEA
1 stop9h 36mFrontier
Thu 8/283:25 pmSEA - IAD
1 stop12h 05mFrontier
Deal found 6/10$270
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.
Sat 8/236:09 pmIAD - SEA
Nonstop5h 42mAlaska Airlines
Tue 8/2611:30 pmSEA - IAD
Nonstop5h 02mAlaska Airlines
Deal found 6/10$277
This United 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/112:55 pmIAD - SEA
1 stop9h 30mUnited Airlines
Wed 11/58:00 amSEA - IAD
Nonstop5h 07mUnited Airlines
Deal found 6/10$283
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/1912:46 pmIAD - SEA
1 stop13h 01mSun Country Air
Mon 7/2111:59 pmSEA - IAD
1 stop8h 44mSun Country Air
Deal found 6/10$289
This Trip.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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/145:25 pmIAD - SEA
1 stop9h 19mMultiple Airlines
Fri 7/187:05 amSEA - IAD
1 stop9h 14mMultiple Airlines
Deal found 6/10$302
This Trip.com 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/88:10 amIAD - SEA
1 stop11h 44mHawaiian Airlines
Tue 7/1511:30 pmSEA - IAD
Nonstop4h 57mHawaiian Airlines
Deal found 6/9$304
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/147:30 amIAD - SEA
Nonstop5h 47mDelta
Wed 7/239:55 pmSEA - IAD
Nonstop5h 02mDelta
Deal found 6/10$317
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/235:35 pmIAD - SEA
1 stop10h 40mSouthwest
Thu 7/315:00 amSEA - IAD
1 stop11h 05mSouthwest
Deal found 6/11$322

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 12, 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 7/29

1:06 pm-8:41 pm

1 stop10h 35m

Seattle/Tacoma Intl

Tue 8/5

9:41 pm-9:53 am

1 stop9h 12m

$267

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 8/18

7:30 am-2:06 pm

1 stop9h 36m

Seattle/Tacoma Intl

Thu 8/28

3:25 pm-6:30 am

1 stop12h 05m

$270

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 8/23

7:35 am-10:20 am

Nonstop5h 45m

Seattle/Tacoma Intl

Wed 8/27

9:55 pm-5:55 am

Nonstop5h 00m

$277

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 8/23

6:09 pm-8:51 pm

Nonstop5h 42m

Seattle/Tacoma Intl

Sat 8/30

7:59 pm-4:47 pm

1 stop17h 48m

$287

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 7/19

12:46 pm-10:47 pm

1 stop13h 01m

Seattle/Tacoma Intl

Mon 7/21

11:59 pm-11:43 am

1 stop8h 44m

$289

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 8/6

10:06 pm-12:56 am

Nonstop5h 50m

Seattle/Tacoma Intl

Tue 8/12

11:20 pm-7:17 am

Nonstop4h 57m

$298

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 7/14

5:25 pm-11:44 pm

1 stop9h 19m

Seattle/Tacoma Intl

Fri 7/18

7:05 am-7:19 pm

1 stop9h 14m

$302

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 7/8

8:10 am-4:54 pm

1 stop11h 44m

Seattle/Tacoma Intl

Tue 7/15

11:30 pm-7:27 am

Nonstop4h 57m

$304

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 7/23

5:35 pm-1:15 am

1 stop10h 40m

Seattle/Tacoma Intl

Thu 7/31

5:00 am-7:05 pm

1 stop11h 05m

$322

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 7/5

12:40 pm-10:47 pm

1 stop13h 07m

$145

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/10

Showing 1-10 of 18 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 June 9, 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 66 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 July is currently the most expensive (average of $391). 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 12, 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 19% 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 8, 2025.

Travelers seeking maximum savings on their Washington, D.C. Dulles Intl Airport to Seattle flight should consider departing on Sunday at noon 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 June 12, 2025.

The most flights from IAD to SEA are scheduled on a Wednesday (31 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (3 on average).

Rainfall in Seattle by month

Plan your trip to Seattle by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Seattle ranges from 0.7 - 6.6 inches per month. November is typically the wettest month, when rainfall can reach 6.6 in. July is typically the driest time to visit Seattle when rainfall is around 0.7 in.

Temperature in Seattle by month

Plan your trip to Seattle by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Seattle, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 66.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 41.0 F).

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 12, 2025.
Get a feel of what it's like to fly with Alaska Airlines, Southwest and Delta from Washington, D.C. to Seattle by reading reviews from past customers. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Southwest
8.0
Very good
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very good
7,950 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Hawaiian Airlines
7.9
Good
2,494 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

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 16 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 $267. Other airlines that can offer you cheap pricing are Frontier, from $270, and Alaska Airlines, from $277. American Airlines is currently priced 35% 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 Sun Country Air, which is currently one of the cheapest options available, starting at $145. Alaska Airlines flights start at $148 while deals on United Airlines start at $149 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 (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 $130. On average you can expect to pay $1,025. The most popular route, (Washington, D.C. Dulles Intl - Seattle/Tacoma Intl), can usually be booked for $277.

  • 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 July is currently the most expensive (average of $391). 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
SeaTac
Tukwila
Tacoma
Lakewood
Ocean Shores
Lacey
Leavenworth
Federal Way
Lynnwood
Olympia
Shoreline
Kent
Cle Elum
Centralia
Kirkland
Aberdeen
Renton
Shelton
Silverdale
Issaquah

Browse thousands of different options on Cheapflights for your next trip

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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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$111Average$218FlexibilityNo cancel feeOn-time62%
Sun Country AirCheapest$144Average$370FlexibilityNo cancel feeOn-time83%
Hawaiian AirlinesCheapest$168Average$387FlexibilityNo cancel feeOn-time85%
DeltaCheapest$221Average$382FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$262Average$432FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$285Average$469FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$297Average$515FlexibilityNo cancel feeOn-time71%

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