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Cheap flights from Seattle to Washington, D.C. Dulles Intl Airport from C$ 211

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 9/1. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — IAD
11 Oct — 18 Oct1
1 adult
1 adult, Economy

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl are usually found in October or February, booked 77 days in advance, depart on a Thursday or Saturday 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 11 September 2025.

Round-trip from

C$ 356

One-way from

C$ 211

Popular in

December

Cheapest in

October

Average price

C$ 497

Good round-trip deal

C$ 363 or less

Good one-way deal

C$ 1,059 or less
Delta
  • Delta
  • 4/10-6/10
  • Nonstop
  • 10h 59m total
  • Seattle to Washington, D.C.
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Southwest
  • Southwest
  • 9/1
  • 1 total stop
  • 6h 45m total
  • Seattle to Washington, D.C.
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Highest demand for flights based on searches. 5% potential increase in price (C$ 47 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease (C$ 20 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 Seattle/Tacoma Intl to Washington, D.C. Dulles Intl.
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Price to beat on a one-way 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 11 September 2025.

Thu 2/109:55 p.m.SEA - IAD
Nonstop5h 06mDelta
Wed 8/107:35 a.m.IAD - SEA
Nonstop5h 53mDelta
Deal found 11/9C$ 356
Fri 31/1012:35 p.m.SEA - IAD
1 stop6h 50mSouthwest
Fri 14/117:50 p.m.IAD - SEA
1 stop7h 45mSouthwest
Deal found 10/9C$ 366
Sat 1/1112:35 p.m.SEA - IAD
1 stop7h 25mSouthwest
Tue 4/115:45 p.m.IAD - SEA
1 stop8h 10mSouthwest
Deal found 10/9C$ 367
Thu 2/107:00 a.m.SEA - IAD
1 stop7h 37mUnited Airlines
Mon 6/105:55 p.m.IAD - SEA
Nonstop5h 49mUnited Airlines
Deal found 11/9C$ 370
Wed 5/118:10 a.m.SEA - IAD
2 stops11h 00mSouthwest
Thu 13/117:50 p.m.IAD - SEA
1 stop7h 45mSouthwest
Deal found 9/9C$ 371
Thu 13/115:35 a.m.SEA - IAD
1 stop10h 25mSouthwest
Sun 16/117:50 p.m.IAD - SEA
1 stop7h 45mSouthwest
Deal found 11/9C$ 373
Wed 29/107:10 a.m.SEA - IAD
2 stops12h 55mSouthwest
Mon 3/115:45 p.m.IAD - SEA
1 stop8h 10mSouthwest
Deal found 9/9C$ 374
Tue 14/107:10 a.m.SEA - IAD
1 stop7h 45mSouthwest
Tue 21/106:40 p.m.IAD - SEA
1 stop8h 05mSouthwest
Deal found 10/9C$ 378
Wed 22/1011:00 a.m.SEA - IAD
1 stop9h 05mSouthwest
Tue 28/107:40 a.m.IAD - SEA
2 stops18h 15mSouthwest
Deal found 11/9C$ 380
Fri 14/115:35 a.m.SEA - IAD
1 stop10h 25mSouthwest
Sun 23/115:05 a.m.IAD - SEA
1 stop8h 35mSouthwest
Deal found 10/9C$ 382
Thu 9/104:48 p.m.SEA - IAD
Nonstop4h 52mDelta
Thu 16/107:35 a.m.IAD - SEA
Nonstop5h 53mDelta
Deal found 10/9C$ 384
Thu 30/1012:41 p.m.SEA - IAD
1 stop8h 34mUnited Airlines
Sat 1/115:55 p.m.IAD - SEA
Nonstop5h 59mUnited Airlines
Deal found 10/9C$ 388

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 11 September 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 11/10

4:48 p.m.-12:40 a.m.

Nonstop4h 52m

Washington, D.C. Dulles Intl

Tue 14/10

7:35 a.m.-10:28 a.m.

Nonstop5h 53m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 7/1

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

Nonstop5h 00m

Washington, D.C. Dulles Intl

Mon 19/1

6:55 p.m.-9:40 p.m.

Nonstop5h 45m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 2/10

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

Nonstop5h 03m

Washington, D.C. Dulles Intl

Mon 6/10

6:25 a.m.-9:08 a.m.

Nonstop5h 43m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Sat 11/10

4:48 p.m.-12:40 a.m.

Nonstop4h 52m

Washington, D.C. Dulles Intl

Sun 12/10

7:35 a.m.-10:28 a.m.

Nonstop5h 53m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 9/1

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

Nonstop5h 00m

Washington, D.C. Dulles Intl

Sun 18/1

6:55 p.m.-9:40 p.m.

Nonstop5h 45m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 15/10

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

Nonstop5h 03m

Washington, D.C. Dulles Intl

Mon 20/10

6:25 a.m.-9:08 a.m.

Nonstop5h 43m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 9/1

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

Nonstop5h 00m

Washington, D.C. Dulles Intl

Fri 23/1

6:55 p.m.-9:40 p.m.

Nonstop5h 45m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 30/10

4:48 p.m.-12:40 a.m.

Nonstop4h 52m

Washington, D.C. Dulles Intl

Mon 3/11

7:35 a.m.-10:28 a.m.

Nonstop5h 53m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 10/10

4:48 p.m.-12:40 a.m.

Nonstop4h 52m

Washington, D.C. Dulles Intl

Sun 12/10

7:35 a.m.-10:28 a.m.

Nonstop5h 53m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 8/1

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

Nonstop5h 00m

Washington, D.C. Dulles Intl

Thu 22/1

6:55 p.m.-9:40 p.m.

Nonstop5h 45m

C$ 356

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/9

Showing 1-10 of 24 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 29 August 2025.

Booking 77 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 11 September 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 evening. If you’re flexible enough to do this you can expect to save up to 75% on your trip compared to booking a flight at noon.

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 11 September 2025.
Read reviews from past customers who have flown Alaska Airlines and Hawaiian Airlines 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

Entertainment

7.0

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Food

7.1

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

Entertainment

7.0

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Food

7.1

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
2,723 reviews
Alaska Airlines
8.0
Very good
10,000 reviews
Check prices

Entertainment

7.0

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Food

7.1

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 22 flights from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl per day from 2 different airlines.

  • How long is the flight from Seattle to Washington, D.C. Dulles Intl Airport?

    Delta and Alaska Airlines can get you from Seattle to Washington, D.C. Dulles Intl Airport in just under 4h 52m. Your travel time will be generally consistent. Seattle and Washington, D.C. Dulles Intl Airport are separated by a distance of 3700 km. All flights are typically direct.

  • 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$ 265 on this airline. An additional option worth looking into is Hawaiian Airlines, starting at C$ 363. Alaska Airlines is 51% cheaper than the average price of flights available within the next 90 days to this destination.

  • 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 (83%).

  • 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$ 888, our data shows the cheapest flight currently is C$ 363. When looking at the most popular route, (Seattle/Tacoma Intl - Washington, D.C. Dulles Intl), you can expect to pay C$ 356 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

Browse thousands of different options on Cheapflights for your next trip

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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 2 airlines flying from Seattle to Dulles Intl

Discover the top 2 airlines 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 11 September 2025.
AirlineCheapestAverageFlexibilityOn-time
Alaska AirlinesCheapestC$ 265AverageC$ 392FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Hawaiian AirlinesCheapestC$ 363AverageC$ 363FlexibilityNo cancel feeOn-time85%
Search Hawaiian Airlines flights

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Can Cheapflights find flights from Seattle to Dulles Intl with no change fees?

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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