Find flights
Deals
When to book
FAQs

Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £151

IAD — SEA
2 Oct — 9 Oct1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Dulles Intl to Seattle

Enter your travel dates to find the best prices.

Cheapest flights from Dulles Intl to Seattle

Thu 29/1007:02 -
Nonstop5h 42m
Thu 29/1013:40 -
2 stops25h 10m
Deal found 2/9£244
Sat 3/1007:02 -
Nonstop5h 42m
Sat 10/1015:56 -
Nonstop5h 03m
Deal found 2/9£261
Wed 14/1009:38 -
Nonstop5h 42m
Wed 21/1015:56 -
Nonstop5h 03m
Deal found 31/8£262
Tue 6/1007:02 -
Nonstop5h 42m
Tue 13/1015:56 -
Nonstop5h 03m
Deal found 29/8£276
Fri 16/1007:05 -
Nonstop5h 51m
Mon 19/1014:50 -
Nonstop4h 59m
Deal found 2/9£279
Fri 2/1015:36 -
1 stop9h 23m
Mon 5/1008:25 -
Nonstop5h 06m
Deal found 31/8£283
Thu 1/1013:05 -
Nonstop5h 46m
Sun 4/1008:25 -
Nonstop5h 06m
Deal found 31/8£288
Thu 19/1117:17 -
Nonstop5h 56m
Sun 22/1121:45 -
Nonstop4h 55m
Deal found 31/8£289
Mon 28/907:00 -
Nonstop5h 37m
Sun 4/1021:36 -
Nonstop5h 04m
Deal found 29/8£290
Fri 2/1017:57 -
Nonstop5h 47m
Sun 4/1021:36 -
Nonstop5h 04m
Deal found 29/8£291

Find flight deals from Dulles Intl to Seattle

Round-trip from

£244

One-way from

£151

Popular in

June

Cheapest in

January

Average price

£289

Good one-way deal

£145 or less
Alaska Airlines
  • Alaska Airlines
  • 29/10-29/10
  • 2 total stops
  • 30h 52m total
  • Washington, D.C. to Seattle
Search Deals
Alaska Airlines
  • Alaska Airlines
  • 15/11
  • 1 total stop
  • 17h 42m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 21% potential increase in price (£58 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£8 potential savings vs. average return price).
Search Deals
Average for round-trip flights in September 2026
Search Deals
Price to beat on a one-way flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl.
Search Deals

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

Cheapest return flight

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Tue 3/11

07:05-09:56

Nonstop5h 51m

Seattle/Tacoma Intl

Mon 9/11

16:30-00:20

Nonstop4h 50m

£279
Fastest return journey

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Thu 1/10

07:25-10:05

Nonstop5h 40m

Seattle/Tacoma Intl

Wed 7/10

14:50-22:49

Nonstop4h 59m

£279

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Sat 31/10

07:05-09:56

Nonstop5h 51m

Seattle/Tacoma Intl

Tue 10/11

16:30-00:20

Nonstop4h 50m

£279

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Fri 9/10

19:24-09:28

1 stop17h 04m

Seattle/Tacoma Intl

Sun 18/10

21:36-05:40

Nonstop5h 04m

£286

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Tue 6/10

13:05-15:51

Nonstop5h 46m

Seattle/Tacoma Intl

Tue 13/10

13:56-00:58

1 stop8h 02m

£286

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Sat 3/10

19:24-09:28

1 stop17h 04m

Seattle/Tacoma Intl

Sat 10/10

15:56-23:59

Nonstop5h 03m

£286

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Sat 31/10

08:20-13:55

1 stop8h 35m

Seattle/Tacoma Intl

Tue 10/11

08:09-16:08

Nonstop4h 59m

£286

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Sat 24/10

12:45-18:44

1 stop8h 59m

Seattle/Tacoma Intl

Sat 7/11

14:30-00:30

1 stop7h 00m

£293

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Thu 12/11

07:00-10:05

Nonstop6h 05m

Seattle/Tacoma Intl

Sun 15/11

16:30-00:20

Nonstop4h 50m

£293

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Tue 6/10

19:24-22:33

1 stop30h 09m

Seattle/Tacoma Intl

Tue 13/10

15:56-23:59

Nonstop5h 03m

£296

Flights are sorted by cheapest return flights first.

Deals found on 29/8

Showing 1-10 of 22 resultsSorted by cheapest first
1
2
3

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 return price

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 20 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 £166). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £398). 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.

How much does it cost for a return flight from Washington, D.C. Dulles Intl Airport to Seattle?

Airfare is typical for this route at the moment.

Washington, D.C. Dulles Intl Airport to Seattle flights typically cost between £226 and £352 in October.
The cheapest return price found within the last 5 days was £244 on Alaska Airlines (29 Oct–29 Oct).

Related info for your journey

  • What airport do you fly into for flights to Seattle from Washington, D.C. Dulles Intl?

    Located just 11.4 mi from the city center, Seattle/Tacoma Intl is the airport most travelers will use when flying to Seattle from Washington, D.C. Dulles Intl. Booking flights from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl (SEA) should be relatively easy as there are 18 daily inbound flights from Washington, D.C. Dulles Intl from 0 different airlines.

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

    Alaska Airlines and Delta can get you from Washington, D.C. Dulles Intl Airport to Seattle in just under 5h 40m. Your travel time will be generally consistent. The distance from Washington, D.C. Dulles Intl Airport to Seattle is about 2299 mi. Most flights are nonstop.

  • 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 Finnair (96%), Japan Airlines (89%) and United Airlines (82%).

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

    Looking for the cheapest flight from Washington, D.C. Dulles Intl Airport to Seattle? While on average our users pay £409, our data indicates the cheapest price to be £145. The most popular route (Washington, D.C. Dulles Intl - Seattle/Tacoma Intl), is priced around £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 holiday 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 £166). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £398). 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 Seattle?

Book flights to Seattle if you plan to visit one of these locations
Federal Way
SeaTac

Browse thousands of different options on Cheapflights for your next trip

Fly with Cheapflights

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.

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.