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Cheap flights from Seattle to Washington, D.C. Dulles Intl Airport from C$ 206

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 2/9. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — IAD
4 Aug — 11 Aug1
1 adult

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl are usually found in September or February, booked 52 days in advance, depart on a Saturday or Thursday and return on a Monday

Cheap flight deals from Seattle to Dulles Intl

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Dulles Intl (IAD). 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 30 July 2025.

Round-trip from

C$ 354

One-way from

C$ 206

Popular in

December

Cheapest in

September

Average price

C$ 592

Good round-trip deal

C$ 390 or less
Alaska Airlines
  • Alaska Airlines
  • 6/9-30/9
  • Nonstop
  • 10h 50m total
  • Seattle to Washington, D.C.
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Hawaiian Airlines
  • Hawaiian Airlines
  • 2/9
  • Nonstop
  • 5h 03m total
  • Seattle to Washington, D.C.
Search Deals
Highest demand for flights based on searches. 6% potential increase in price (C$ 51 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease (C$ 22 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 Seattle/Tacoma Intl to Washington, D.C. Dulles Intl.
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Find flight deals from Seattle to Dulles Intl

Cheapest flights from Seattle to Dulles Intl
Explore the most affordable flight options available from Seattle to Dulles Intl. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 30 July 2025.

Sat 6/94:20 p.m.SEA - IAD
Nonstop5h 03mAlaska Airlines
Sat 27/99:00 a.m.IAD - SEA
Nonstop5h 43mAlaska Airlines
Deal found 30/7C$ 354
Wed 17/911:30 p.m.SEA - IAD
Nonstop5h 03mHawaiian Airlines
Sun 21/99:00 a.m.IAD - SEA
Nonstop5h 43mHawaiian Airlines
Deal found 29/7C$ 363
Sat 20/910:55 p.m.SEA - IAD
Nonstop5h 03mUnited Airlines
Tue 23/98:20 a.m.IAD - SEA
1 stop10h 12mUnited Airlines
Deal found 29/7C$ 368
Thu 28/89:55 p.m.SEA - IAD
Nonstop5h 00mDelta
Mon 1/97:35 a.m.IAD - SEA
Nonstop5h 45mDelta
Deal found 29/7C$ 410
Sat 6/95:00 a.m.SEA - IAD
1 stop7h 00mSouthwest
Tue 9/95:45 a.m.IAD - SEA
2 stops12h 25mSouthwest
Deal found 29/7C$ 417

Cheapflights Fare Finder

 
Customize your flight search to find flights from Seattle to Dulles Intl 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 629,999 searches. Data last updated 30 July 2025.
Use the filters below to find and compare flights from Seattle to Washington, D.C. Dulles Intl Airport that are best for you.

Fly from

Seattle

Fly to

Dulles Intl

Route

Depart

Return

Price

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 6/9

4:20 p.m.-12:23 a.m.

Nonstop5h 03m

Washington, D.C. Dulles Intl

Sat 27/9

9:00 a.m.-11:43 a.m.

Nonstop5h 43m

C$ 354

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 17/9

11:30 p.m.-7:33 a.m.

Nonstop5h 03m

Washington, D.C. Dulles Intl

Sun 21/9

9:00 a.m.-11:43 a.m.

Nonstop5h 43m

C$ 363

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 20/9

10:55 p.m.-6:58 a.m.

Nonstop5h 03m

Washington, D.C. Dulles Intl

Tue 23/9

8:20 a.m.-3:32 p.m.

1 stop10h 12m

C$ 368

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 6/9

5:00 a.m.-3:00 p.m.

1 stop7h 00m

Washington, D.C. Dulles Intl

Tue 9/9

5:45 a.m.-3:10 p.m.

2 stops12h 25m

C$ 417

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 28/8

9:55 p.m.-5:55 a.m.

Nonstop5h 00m

Washington, D.C. Dulles Intl

Tue 2/9

8:23 p.m.-8:14 p.m.

1 stop26h 51m

C$ 450

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Tue 2/9

4:20 p.m.-12:23 a.m.

Nonstop5h 03m

C$ 206

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 17/10

6:30 p.m.-5:20 p.m.

1 stop19h 50m

C$ 211

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 20/8

8:59 p.m.-4:47 p.m.

1 stop16h 48m

C$ 212

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 13/9

11:58 p.m.-11:28 a.m.

1 stop8h 30m

C$ 219

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 18/9

9:55 p.m.-6:01 a.m.

Nonstop5h 06m

C$ 233

Flights are sorted by cheapest round-trip flights first.

Deals found on 29/7

Showing 1-10 of 11 results
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Best time to book a flight from Seattle to Dulles Intl

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

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

Use this chart to determine the optimal time to book a round-trip flight from Seattle to Dulles Intl. Price data was last updated on 25 July 2025.

Booking 52 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to Washington, D.C. Dulles Intl Airport. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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

Currently, February is the cheapest month in which you can book a flight from Seattle to Washington, D.C. Dulles Intl Airport (average of C$ 256). Flying from Seattle to Washington, D.C. Dulles Intl Airport in October is currently the most expensive (average of C$ 352). 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 SEA to IAD?

Find hourly flight availability from Seattle to Dulles Intl. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 30 July 2025.

A simple way to save on the total cost of your ticket is to fly from Seattle to Washington, D.C. Dulles Intl Airport in the afternoon. If you’re flexible enough to do this you can expect to save up to 73% on your trip compared to booking a flight at noon.

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

Explore weekly flight availability from Seattle to Dulles Intl. 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 30 July 2025.

The most flights from SEA to IAD are scheduled on a Tuesday (32 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (11 on average).

Reviews of airlines servicing Dulles Intl

Get insights into the airlines that provide service to Dulles Intl. 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 Dulles Intl. Reviews last updated 30 July 2025.
Read reviews from past customers who have flown Alaska Airlines,Southwest, andDelta from Seattle to Washington, D.C. Dulles Intl Airport. 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
Check prices

Overall

8.0

Boarding

8.1

Food

7.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Overall

8.0

Boarding

8.1

Food

7.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Southwest
8.0
Very good
4,241 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Overall

8.0

Boarding

8.1

Food

7.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Delta
8.0
Very good
7,980 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Overall

8.0

Boarding

8.1

Food

7.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Hawaiian Airlines
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Overall

8.0

Boarding

8.1

Food

7.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
United Airlines
7.4
Good
8,896 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Overall

8.0

Boarding

8.1

Food

7.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.

Related info for your journey

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

    If you book a flight to Washington, D.C. Dulles Intl from Seattle, you will be flying from Seattle/Tacoma Intl, which is the city’s only airport. Seattle/Tacoma Intl (SEA) is located 18.4 km from the centre of Seattle. There are 23 flights from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl per day from 1 airline.

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

    Our cheapest airline available from Seattle to Washington, D.C. Dulles Intl Airport is Alaska Airlines. Our recent data shows that you can find tickets from as low as C$ 354 on this airline. Additional options worth looking into are Hawaiian Airlines and United Airlines, starting at C$ 363 and C$ 368 round-trip. Alaska Airlines is 35% cheaper than the average price of flights available within the next 90 days to this destination.

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

    The cheapest airline one-way is Hawaiian Airlines, with whom users have recently found tickets for as low as C$ 206. However, be on the lookout for offers from Sun Country Air and Alaska Airlines, as they are both options that can get you from Seattle to Washington, D.C. Dulles Intl Airport for a low price.

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

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Seattle to Washington, D.C. Dulles Intl Airport on time: Austrian Airlines (87%), Brussels Airlines (87%), Lufthansa (86%).

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

    While on average a flight from Seattle to Washington, D.C. Dulles Intl Airport is generally C$ 878, our data shows the cheapest flight currently is C$ 388. When looking at the most popular route, (Seattle/Tacoma Intl - Washington, D.C. Dulles Intl), you can expect to pay C$ 411 for that flight.

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

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

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

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

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

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

    Currently, February is the cheapest month in which you can book a flight from Seattle to Washington, D.C. Dulles Intl Airport (average of C$ 256). Flying from Seattle to Washington, D.C. Dulles Intl Airport in October is currently the most expensive (average of C$ 352). 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

Travelling 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
Herndon
Warrenton
Hanover
Reston
Fairfax
Ellicott City
Oxon Hill
Gaithersburg
Winchester
Arlington
Alexandria
Manassas
Fredericksburg
Rockville

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Alternative routes for Seattle to Dulles Intl

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to Reagan-National flights

Top airline flying from Seattle to Dulles Intl

Discover the top airline that operate flights from Seattle to Dulles Intl. 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 629,999 searches. Data last updated 30 July 2025.
AirlineCheapestAverageFlexibilityOn-time
Alaska AirlinesCheapestC$ 264AverageC$ 395FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights

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How does Cheapflights help users find flights from Seattle to Dulles Intl?

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Cheapflights does show flights with no change fees to all users. To see these options for flights from Seattle to Dulles Intl, users can toggle the no change fees filter when performing a flight search.

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