Seattle

$148+ 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 8/13. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
Jul 23 — Jul 301
We work with more than 300 partners to bring you better travel deals

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”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

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 July 18, 2025.

Round-trip from

$257
(American Airlines)

One-way from

$148
(Alaska Airlines)

Popular in

December

Cheapest in

February

Average price

$457

Good round-trip deal

$364 or less

Good one-way deal

$201 or less
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. 2% potential increase in price ($11 potential increase over avg. RT price).
Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
Average for round-trip flights in July 2025
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.

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 July 18, 2025.

This American Airlines deal was found by Cheapflights users on 7/17. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/32:21 pmIAD - SEA
1 stop11h 08mAmerican Airlines
Tue 9/95:26 amSEA - IAD
1 stop8h 24mAmerican Airlines
Deal found 7/17$257
This Kiwi.com deal was found by Cheapflights users on 7/16. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/136:30 amIAD - SEA
Nonstop5h 47mHawaiian Airlines
Wed 8/204:20 pmSEA - IAD
Nonstop5h 00mHawaiian Airlines
Deal found 7/16$261
This SmartFares deal was found by Cheapflights users on 7/15. 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.
Sat 8/309:00 amIAD - SEA
Nonstop5h 43mAlaska Airlines
Sat 9/611:30 pmSEA - IAD
Nonstop5h 03mAlaska Airlines
Deal found 7/15$264
This Frontier deal was found by Cheapflights users on 7/16. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/117:30 amIAD - SEA
1 stop9h 36mFrontier
Thu 8/143:11 pmSEA - IAD
1 stop12h 23mFrontier
Deal found 7/16$286
This Cheapflightsfares deal was found by Cheapflights users on 7/16. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/1611:52 amIAD - SEA
1 stop8h 33mSun Country Air
Sun 10/1911:59 pmSEA - IAD
1 stop8h 27mSun Country Air
Deal found 7/16$289
This Delta deal was found by Cheapflights users on 7/17. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/131:00 pmIAD - SEA
1 stop12h 07mDelta
Tue 9/309:55 pmSEA - IAD
Nonstop5h 06mDelta
Deal found 7/17$300
This Southwest deal was found by Cheapflights users on 7/16. 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.
Sat 8/305:05 pmIAD - SEA
1 stop7h 45mSouthwest
Sat 9/207:35 amSEA - IAD
2 stops12h 10mSouthwest
Deal found 7/16$302

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 July 18, 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

Wed 9/3

2:21 pm-10:29 pm

1 stop11h 08m

Seattle/Tacoma Intl

Tue 9/9

5:26 am-4:50 pm

1 stop8h 24m

$257

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 8/13

6:30 am-9:17 am

Nonstop5h 47m

Seattle/Tacoma Intl

Wed 8/20

4:20 pm-12:20 am

Nonstop5h 00m

$261

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 8/30

9:00 am-11:43 am

Nonstop5h 43m

Seattle/Tacoma Intl

Sat 9/6

11:30 pm-7:33 am

Nonstop5h 03m

$264

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 8/11

7:30 am-2:06 pm

1 stop9h 36m

Seattle/Tacoma Intl

Thu 8/14

3:11 pm-6:34 am

1 stop12h 23m

$286

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 8/13

1:05 pm-3:53 pm

Nonstop5h 48m

Seattle/Tacoma Intl

Tue 8/19

5:35 pm-5:24 am

1 stop8h 49m

$287

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 10/16

11:52 am-5:25 pm

1 stop8h 33m

Seattle/Tacoma Intl

Sun 10/19

11:59 pm-11:26 am

1 stop8h 27m

$289

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 9/13

1:00 pm-10:07 pm

1 stop12h 07m

Seattle/Tacoma Intl

Tue 9/30

9:55 pm-6:01 am

Nonstop5h 06m

$300

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 8/30

5:05 pm-9:50 pm

1 stop7h 45m

Seattle/Tacoma Intl

Sat 9/20

7:35 am-10:45 pm

2 stops12h 10m

$302

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 8/13

8:10 am-4:54 pm

1 stop11h 44m

$148

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 8/18

7:35 am-10:20 am

Nonstop5h 45m

$149

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/17

Showing 1-10 of 17 results
1
2

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 11, 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 $388). 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 July 18, 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 13, 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 July 18, 2025.

The most flights from IAD to SEA are scheduled on a Thursday (31 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (11 on average).

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 July 18, 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.

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

Crew

8.5

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.

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

Crew

8.5

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.

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

Crew

8.5

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.
8.0
Very good

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

Crew

8.5

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.

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

Crew

8.5

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.

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

Crew

8.5

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 20 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 $257. Other airlines that can offer you cheap pricing are Hawaiian Airlines, from $261, and Alaska Airlines, from $264. American Airlines is currently priced 37% 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 Alaska Airlines, which is currently one of the cheapest options available, starting at $148. Delta flights start at $149 while deals on Sun Country Air start at $153 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 $141. On average you can expect to pay $1,168. The most popular route, (Washington, D.C. Dulles Intl - Seattle/Tacoma Intl), can usually be booked for $273.

  • 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 $388). 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
Lacey
Leavenworth
Renton
Olympia
Puyallup
Cle Elum
Shoreline
Kent
Chehalis
Kirkland
Aberdeen
Federal Way
Shelton
Silverdale

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

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 July 18, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$111Average$240FlexibilityNo cancel feeOn-time62%
Sun Country AirCheapest$144Average$370FlexibilityNo cancel feeOn-time83%
Hawaiian AirlinesCheapest$168Average$391FlexibilityNo cancel feeOn-time85%
DeltaCheapest$218Average$382FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$263Average$426FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$284Average$470FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$297Average$522FlexibilityNo cancel feeOn-time71%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.