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Cheap flights from Seattle to Washington, D.C. Dulles Intl Airport from C$ 178

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 24/1. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — IAD
11 Jan — 18 Jan1
1 adult
1 adult, Economy, 0 bags

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl are usually found in October or February, booked 41 days in advance, depart on a Thursday or Saturday and return on a Tuesday

Cheap flight deals from Seattle to Dulles Intl

Enter your travel dates to find the best prices.

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 12 December 2025.

Wed 31/1211:15 p.m.SEA - IAD
Nonstop4h 56mUnited Airlines
Thu 8/15:55 p.m.IAD - SEA
Nonstop6h 02mUnited Airlines
Deal found 10/12C$ 439
Wed 31/1211:15 p.m.SEA - IAD
Nonstop4h 56mUnited Airlines
Fri 9/15:17 p.m.IAD - SEA
1 stop8h 26mUnited Airlines
Deal found 10/12C$ 447
Wed 31/1211:59 p.m.SEA - IAD
1 stop8h 29mUnited Airlines
Tue 6/15:55 p.m.IAD - SEA
Nonstop6h 02mUnited Airlines
Deal found 10/12C$ 452
Wed 31/123:55 p.m.SEA - IAD
2 stops14h 54mDelta
Wed 7/17:30 a.m.IAD - SEA
Nonstop5h 59mDelta
Deal found 10/12C$ 484
Thu 25/1211:15 p.m.SEA - IAD
Nonstop4h 56mUnited Airlines
Thu 8/15:55 p.m.IAD - SEA
Nonstop6h 02mUnited Airlines
Deal found 10/12C$ 514
Wed 31/1211:15 p.m.SEA - IAD
Nonstop4h 56mUnited Airlines
Mon 5/15:55 p.m.IAD - SEA
Nonstop6h 02mUnited Airlines
Deal found 10/12C$ 527
Thu 25/129:06 a.m.SEA - IAD
1 stop9h 09mUnited Airlines
Wed 7/15:55 p.m.IAD - SEA
Nonstop6h 02mUnited Airlines
Deal found 11/12C$ 528
Wed 31/123:55 p.m.SEA - IAD
2 stops14h 54mDelta
Tue 6/17:30 a.m.IAD - SEA
Nonstop5h 59mDelta
Deal found 10/12C$ 539
Mon 29/123:30 p.m.SEA - IAD
Nonstop4h 57mDelta
Wed 7/17:30 a.m.IAD - SEA
Nonstop5h 59mDelta
Deal found 10/12C$ 541

Find 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 12 December 2025.

Round-trip from

C$ 298

One-way from

C$ 178

Popular in

November

Cheapest in

October

Average price

C$ 662
United Airlines
  • United Airlines
  • 16/1-19/1
  • Nonstop
  • 11h 08m total
  • Seattle to Washington, D.C.
Search Deals
American Airlines
  • American Airlines
  • 24/1
  • 1 total stop
  • 7h 31m total
  • Seattle to Washington, D.C.
Search Deals
Highest demand for flights based on searches. 5% potential increase in price (C$ 47 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 15 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
Search Deals

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 12 December 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 17/1

6:05 a.m.-6:56 p.m.

1 stop9h 51m

Washington, D.C. Dulles Intl

Tue 20/1

2:15 p.m.-8:46 p.m.

1 stop9h 31m

C$ 302

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 23/1

11:10 p.m.-11:49 a.m.

1 stop9h 39m

Washington, D.C. Dulles Intl

Sun 25/1

6:00 a.m.-10:42 a.m.

1 stop7h 42m

C$ 302

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 15/1

8:40 a.m.-7:21 p.m.

1 stop7h 41m

Washington, D.C. Dulles Intl

Mon 19/1

5:55 p.m.-8:57 p.m.

Nonstop6h 02m

C$ 314

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Mon 26/1

8:10 a.m.-4:16 p.m.

Nonstop5h 06m

Washington, D.C. Dulles Intl

Fri 30/1

5:17 p.m.-10:43 p.m.

1 stop8h 26m

C$ 338

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 16/1

3:20 p.m.-11:10 p.m.

Nonstop4h 50m

Washington, D.C. Dulles Intl

Tue 20/1

7:30 a.m.-10:29 a.m.

Nonstop5h 59m

C$ 342

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 26/2

3:20 p.m.-11:10 p.m.

Nonstop4h 50m

Washington, D.C. Dulles Intl

Fri 13/3

7:00 a.m.-10:01 a.m.

Nonstop6h 01m

C$ 342

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Fri 9/1

3:20 p.m.-11:10 p.m.

Nonstop4h 50m

Washington, D.C. Dulles Intl

Sun 11/1

7:05 a.m.-12:33 p.m.

1 stop8h 28m

C$ 356

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 14/1

3:20 p.m.-11:10 p.m.

Nonstop4h 50m

Washington, D.C. Dulles Intl

Fri 16/1

7:30 a.m.-10:29 a.m.

Nonstop5h 59m

C$ 370

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Wed 11/3

6:59 p.m.-5:27 p.m.

1 stop19h 28m

Washington, D.C. Dulles Intl

Thu 19/3

7:00 a.m.-9:54 a.m.

Nonstop5h 54m

C$ 389

SeattleWashington, D.C.

SEA - IAD

SEAIAD

Seattle/Tacoma Intl

Thu 15/1

8:30 a.m.-4:26 p.m.

Nonstop4h 56m

Washington, D.C. Dulles Intl

Sun 18/1

6:04 p.m.-9:08 p.m.

Nonstop6h 04m

C$ 390

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/12

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 5 December 2025.

Booking 41 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, March is the cheapest month in which you can book a flight from Seattle to Washington, D.C. Dulles Intl Airport (average of C$ 197). Flying from Seattle to Washington, D.C. Dulles Intl Airport in June is currently the most expensive (average of C$ 405). 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 12 December 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 74% on your trip compared to booking a flight at noon.

How much does it cost to fly round-trip from Seattle to Washington, D.C. Dulles Intl Airport?

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 12 December 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
11,429 reviews
Check prices

Overall

8.0

Boarding

8.1

Comfort

7.8

Entertainment

7.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Alaska Airlines
8.0
Very good
11,429 reviews
Alaska Airlines
8.0
Very good
11,429 reviews
Check prices

Overall

8.0

Boarding

8.1

Comfort

7.8

Entertainment

7.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Hawaiian Airlines
7.8
Good
2,818 reviews
Alaska Airlines
8.0
Very good
11,429 reviews
Check prices

Overall

8.0

Boarding

8.1

Comfort

7.8

Entertainment

7.0

Food

7.1

Crew

8.5

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.

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 11 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 United Airlines can get you from Seattle to Washington, D.C. Dulles Intl Airport in just under 7h 41m. Your travel time can differ by up to 2h 10m. Seattle and Washington, D.C. Dulles Intl Airport are separated by a distance of 3700 km. This flight may include one or multiple stops.

  • 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$ 264 on this airline. An additional option worth looking into is Hawaiian Airlines, starting at C$ 362. Alaska Airlines is 52% 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: Copa Airlines (100%), Avianca (97%), United Airlines (96%).

  • 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, March is the cheapest month in which you can book a flight from Seattle to Washington, D.C. Dulles Intl Airport (average of C$ 197). Flying from Seattle to Washington, D.C. Dulles Intl Airport in June is currently the most expensive (average of C$ 405). 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
Silver Spring
Warrenton
Winchester
Hanover
Fairfax
Reston
Ellicott City
Oxon Hill
Gaithersburg
Arlington
Herndon
Manassas
Fredericksburg
Alexandria
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 12 December 2025.
AirlineCheapestAverageFlexibilityOn-time
Alaska AirlinesCheapestC$ 264AverageC$ 390FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights
Hawaiian AirlinesCheapestC$ 362AverageC$ 362FlexibilityNo cancel feeOn-time85%
Search Hawaiian Airlines flights

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

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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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