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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £138

IAD — SEA
26 Oct — 2 Nov1
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

Tue 3/1107:46 -
Nonstop5h 50m
Tue 3/1113:03 -
1 stop25h 37m
Deal found 24/9£262
Wed 9/1207:00 -
Nonstop6h 05m
Wed 9/1212:18 -
1 stop26h 21m
Deal found 24/9£277
Thu 5/1107:05 -
Nonstop5h 51m
Tue 10/1116:30 -
Nonstop4h 50m
Deal found 26/9£279
Thu 5/1107:05 -
Nonstop5h 51m
Mon 9/1116:30 -
Nonstop4h 50m
Deal found 24/9£280
Sat 7/1107:05 -
Nonstop5h 51m
Mon 9/1116:30 -
Nonstop4h 50m
Deal found 24/9£283
Sat 7/1107:46 -
Nonstop5h 50m
Mon 9/1121:49 -
Nonstop4h 55m
Deal found 25/9£283
Sat 7/1107:05 -
Nonstop5h 51m
Tue 10/1116:30 -
Nonstop4h 50m
Deal found 23/9£285
Wed 21/1007:50 -
2 stops28h 08m
Wed 28/1012:14 -
2 stops25h 58m
Deal found 23/9£287
Tue 8/1215:14 -
1 stop9h 44m
Tue 5/108:00 -
Nonstop4h 53m
Deal found 24/9£289

Find flight deals from Dulles Intl to Seattle

Round-trip from

£262

One-way from

£138

Popular in

June

Cheapest in

January

Average price

£301
Alaska Airlines
  • Alaska Airlines
  • 3/11-3/11
  • 1 total stop
  • 31h 27m total
  • Washington, D.C. to Seattle
Search Deals
Frontier
  • Frontier
  • 26/10-31/12
  • 1 total stop
  • 31h 59m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 20% potential increase in price (£59 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

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.

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Price

Cheapest return flight
Fastest return journey

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sun 25/10

07:02-09:44

Nonstop5h 42m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£156

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Tue 27/10

07:02-09:44

Nonstop5h 42m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£156

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 26/10

07:02-09:44

Nonstop5h 42m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£156

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Thu 26/11

17:50-20:56

Nonstop6h 06m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£158

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Thu 26/11

07:00-10:05

Nonstop6h 05m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£158

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Tue 17/11

07:00-10:05

Nonstop6h 05m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£158

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Thu 5/11

07:05-09:56

Nonstop5h 51m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£158

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sun 25/10

06:15-12:20

1 stop9h 05m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£165

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Tue 17/11

17:50-20:56

Nonstop6h 06m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£165

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 30/11

18:15-11:28

1 stop20h 13m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£195

Flights are sorted by cheapest return flights first.

Deals found on 24/9

Showing 1-10 of 20 resultsSorted by cheapest first
1
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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 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 £168). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £408). 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 £252 and £462 in November.
The cheapest return price found within the last 5 days was £262 on Alaska Airlines (3 Nov–3 Nov).

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 13 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 and Alaska Airlines can get you from Washington, D.C. Dulles Intl Airport to Seattle in just under 5h 50m. 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 (89%), Japan Airlines (89%) and Alaska Airlines (84%).

  • 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 £168). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £408). 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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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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