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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £134

IAD — SEA
19 Oct — 26 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 15/1007:02 -
Nonstop5h 42m
Thu 22/1015:56 -
Nonstop5h 03m
Deal found 16/9£211
Fri 16/1007:05 -
Nonstop5h 51m
Tue 27/1022:35 -
1 stop7h 44m
Deal found 16/9£215
Thu 5/1112:30 -
1 stop10h 39m
Sun 8/1113:30 -
1 stop7h 05m
Deal found 17/9£222
Wed 28/1007:02 -
Nonstop5h 42m
Sun 1/1120:48 -
1 stop17h 52m
Deal found 16/9£226
Fri 23/1019:24 -
1 stop17h 04m
Mon 26/1021:36 -
Nonstop5h 04m
Deal found 15/9£230
Fri 9/1017:45 -
Nonstop5h 52m
Mon 12/1023:14 -
Nonstop5h 03m
Deal found 16/9£233
Wed 7/1009:38 -
Nonstop5h 42m
Wed 7/1015:56 -
Nonstop5h 03m
Deal found 16/9£233
Sun 15/1107:00 -
Nonstop6h 05m
Sun 15/1116:30 -
Nonstop4h 50m
Deal found 17/9£237
Sat 10/1016:02 -
1 stop9h 54m
Mon 12/1023:14 -
Nonstop5h 03m
Deal found 17/9£239
Thu 15/1006:10 -
1 stop8h 17m
Thu 22/1023:14 -
Nonstop5h 03m
Deal found 17/9£243
Tue 6/1007:05 -
Nonstop5h 51m
Sat 10/1006:00 -
1 stop14h 16m
Deal found 15/9£244

Find flight deals from Dulles Intl to Seattle

Round-trip from

£211

One-way from

£134

Popular in

June

Cheapest in

January

Average price

£298

Good one-way deal

£204 or less
Alaska Airlines
  • Alaska Airlines
  • 15/10-22/10
  • Nonstop
  • 10h 45m total
  • Washington, D.C. to Seattle
Search Deals
Delta
  • Delta
  • 20/10-31/12
  • 1 total stop
  • 11h 19m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 20% potential increase in price (£57 potential increase over avg. return price).
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Cheapest flight prices on average. 3% potential price decrease (£8 potential savings vs. average return price).
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Average for round-trip flights in September 2026
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Price to beat on a one-way flight from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl.
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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

Fri 23/10

15:47-22:56

1 stop10h 09m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£171

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Thu 17/12

07:00-10:10

Nonstop6h 10m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£179

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sat 2/1

07:00-09:55

Nonstop5h 55m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sat 10/10

17:45-20:37

Nonstop5h 52m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Thu 18/3

07:05-10:05

Nonstop6h 00m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201
Fastest return journey

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 15/3

07:00-09:48

Nonstop5h 48m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Fri 6/11

07:05-09:56

Nonstop5h 51m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sat 17/10

07:05-09:56

Nonstop5h 51m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Tue 24/11

07:00-10:05

Nonstop6h 05m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Tue 16/3

07:15-15:00

1 stop10h 45m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£209

Flights are sorted by cheapest return flights first.

Deals found on 18/9

Showing 1-10 of 24 resultsSorted by cheapest first
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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 54 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 £404). 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 below average for this route at the moment.

Washington, D.C. Dulles Intl Airport to Seattle flights typically cost between £246 and £408 in October.
The cheapest return price found within the last 5 days was £211 on Alaska Airlines (15 Oct–22 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 11 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?

    Delta can get you from Washington, D.C. Dulles Intl Airport to Seattle in just under 8h 09m. Your travel time can differ by up to . The distance from Washington, D.C. Dulles Intl Airport to Seattle is about 2299 mi.

  • 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 (89%), Japan Airlines (89%) and Alaska Airlines (84%).

  • 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 £414, our data indicates the cheapest price to be £183. The most popular route (Washington, D.C. Dulles Intl - Seattle/Tacoma Intl), is priced around £207.

  • 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 £404). 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

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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.

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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.

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