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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £152

IAD — SEA
23 Nov — 30 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

Sun 6/1220:55 -
2 stops21h 48m
Sun 13/1213:36 -
2 stops27h 34m
Deal found 22/10£245
Fri 13/1121:06 -
2 stops21h 06m
Tue 17/1119:48 -
2 stops12h 48m
Deal found 19/10£262
Sun 6/1221:23 -
3 stops21h 20m
Sun 13/1218:19 -
2 stops22h 51m
Deal found 22/10£267
Sat 5/1207:00 -
Nonstop6h 10m
Sat 12/1211:55 -
Nonstop5h 04m
Deal found 21/10£282
Thu 12/1112:31 -
3 stops24h 14m
Wed 18/1116:27 -
2 stops16h 19m
Deal found 22/10£285
Sat 5/1215:14 -
1 stop9h 44m
Tue 8/1208:09 -
Nonstop4h 59m
Deal found 20/10£286
Tue 24/1107:00 -
Nonstop5h 50m
Wed 2/1220:09 -
1 stop18h 30m
Deal found 20/10£289
Sun 6/1207:00 -
Nonstop6h 05m
Sun 13/1208:15 -
Nonstop5h 00m
Deal found 22/10£294
Tue 24/1107:00 -
Nonstop5h 50m
Fri 27/1108:15 -
Nonstop4h 58m
Deal found 21/10£297
Wed 9/1215:14 -
1 stop9h 44m
Sun 13/1208:09 -
Nonstop4h 59m
Deal found 19/10£301

Find flight deals from Dulles Intl to Seattle

Round-trip from

£245

One-way from

£152

Popular in

June

Cheapest in

January

Average price

£361
Frontier
  • Frontier
  • 6/12-13/12
  • 4 total stops
  • 49h 22m total
  • Washington, D.C. to Seattle
Search Deals
Alaska Airlines
  • Alaska Airlines
  • 16/12-31/12
  • 1 total stop
  • 17h 51m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 18% potential increase in price (£52 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 October 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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Route

Depart

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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 8/12

17:55-21:01

Nonstop6h 06m

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 24/11

07:00-10:05

Nonstop6h 05m

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

Sat 12/12

15:14-21:58

1 stop9h 44m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£160

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 8/2

18:53-09:26

1 stop17h 33m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£167

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sun 6/12

18:42-09:32

1 stop17h 50m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£167

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sun 13/12

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

Thu 26/11

09:25-16:26

1 stop10h 01m

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

Mon 8/2

07:15-14:45

1 stop10h 30m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£194

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sat 12/12

17:10-22:04

1 stop7h 54m

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

Tue 20/4

17:38-20:26

Nonstop5h 48m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£208

Flights are sorted by cheapest return flights first.

Deals found on 20/10

Showing 1-10 of 23 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 £170). 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 £259 and £449 in December.
The cheapest return price found within the last 5 days was £245 on Frontier (6 Dec–13 Dec).

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 14 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 6h 09m. 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 (92%), Japan Airlines (87%) and Cathay Pacific (87%).

  • 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 £170). 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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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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