Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £103
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 21/1. Fares are subject to change and may not be available on all flights or dates of travel.
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 5 September 2025.
Round-trip from | £191 |
---|---|
One-way from | £103 |
Popular in | December |
Cheapest in | February |
Average price | £276 |
Find flight deals from Dulles Intl to Seattle
Cheapest flights from Dulles Intl to SeattleExplore 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 5 September 2025.
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 5 September 2025.
Cheapflights Fare Finder
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
Fly to
Route
Depart
Return
Price
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Thu 20/11
07:43-10:35
Nonstop5h 52m
Seattle/Tacoma Intl
Wed 3/12
08:40-16:36
Nonstop4h 56m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Thu 2/10
07:00-09:40
Nonstop5h 40m
Seattle/Tacoma Intl
Mon 6/10
16:20-00:23
Nonstop5h 03m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Fri 17/10
17:55-20:44
Nonstop5h 49m
Seattle/Tacoma Intl
Sat 25/10
08:00-16:09
Nonstop5h 09m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Sun 23/11
07:15-10:19
Nonstop6h 04m
Seattle/Tacoma Intl
Fri 5/12
16:30-00:26
Nonstop4h 56m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Wed 22/10
06:25-09:08
Nonstop5h 43m
Seattle/Tacoma Intl
Sat 25/10
10:14-18:28
Nonstop5h 14m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Wed 5/11
18:13-21:12
Nonstop5h 59m
Seattle/Tacoma Intl
Mon 10/11
22:29-06:23
Nonstop4h 54m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Wed 1/10
07:35-10:16
Nonstop5h 41m
Seattle/Tacoma Intl
Wed 8/10
16:48-00:40
Nonstop4h 52m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Tue 11/11
07:43-10:35
Nonstop5h 52m
Seattle/Tacoma Intl
Sun 16/11
22:29-06:23
Nonstop4h 54m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Tue 25/11
07:15-10:19
Nonstop6h 04m
Seattle/Tacoma Intl
Thu 4/12
16:30-00:26
Nonstop4h 56m
Washington, D.C.Seattle
IAD - SEA
IADSEA
Washington, D.C. Dulles Intl
Wed 29/10
07:43-10:35
Nonstop5h 52m
Seattle/Tacoma Intl
Wed 5/11
22:29-06:23
Nonstop4h 54m
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.
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?
The best time to book flights from Washington, D.C. Dulles Intl Airport to Seattle is 28 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
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 £622). Flying from Washington, D.C. Dulles Intl Airport to Seattle in July is currently the most expensive (average of £946). 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?
When flying from Washington, D.C. Dulles Intl Airport to Seattle, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
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.
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How does Cheapflights help users find flights from Dulles Intl to Seattle?
When you search for this flight from Dulles Intl to Seattle, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.
Why should you use Cheapflights to find cheap flight tickets from Dulles Intl to Seattle?
Cheapflights simply makes it quick and affordable to book flights from Dulles Intl to Seattle by bringing together all flight options from hundreds of airlines and agencies online — and put it in one place for you to choose from. Plus, Cheapflights is 100% free to use for all.
Can Cheapflights find flights from Dulles Intl to Seattle with no change fees?
Need flexible booking options for your flight to Seattle from Dulles Intl? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.
Can Cheapflights notify me if prices for flights from Dulles Intl to Seattle become cheaper?
Yes, Cheapflights offers price alerts on Dulles Intl to Seattle flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.