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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £95

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 5/3. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
9 Mar — 16 Mar1
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
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 7 February 2026.

Tue 7/407:00
IAD
-
SEA
Nonstop5h 53m
Alaska Airlines
Mon 20/414:06
SEA
-
IAD
1 stop24h 16m
Alaska Airlines
Deal found 5/2£170
Tue 7/417:55
IAD
-
SEA
Nonstop5h 58m
United Airlines
Thu 16/408:00
SEA
-
IAD
Nonstop5h 11m
United Airlines
Deal found 6/2£174
Sun 1/307:30
IAD
-
SEA
Nonstop5h 59m
Delta
Sat 7/315:20
SEA
-
IAD
Nonstop4h 50m
Delta
Deal found 6/2£175
Thu 7/517:55
IAD
-
SEA
Nonstop5h 58m
United Airlines
Mon 11/519:05
SEA
-
IAD
1 stop7h 23m
United Airlines
Deal found 7/2£181
Tue 24/307:00
IAD
-
SEA
Nonstop5h 53m
Hawaiian Airlines
Tue 31/321:40
SEA
-
IAD
Nonstop5h 00m
Hawaiian Airlines
Deal found 7/2£182
Sat 28/215:58
IAD
-
SEA
1 stop8h 14m
United Airlines
Wed 4/312:43
SEA
-
IAD
1 stop7h 38m
United Airlines
Deal found 7/2£185
Fri 27/218:27
IAD
-
SEA
Nonstop6h 08m
Alaska Airlines
Thu 5/321:45
SEA
-
IAD
Nonstop4h 55m
Alaska Airlines
Deal found 6/2£192
Thu 5/317:55
IAD
-
SEA
Nonstop6h 01m
United Airlines
Wed 11/308:00
SEA
-
IAD
Nonstop5h 02m
United Airlines
Deal found 5/2£193
Wed 15/419:11
IAD
-
SEA
Nonstop5h 51m
Alaska Airlines
Mon 20/421:11
SEA
-
IAD
1 stop17h 11m
Alaska Airlines
Deal found 6/2£196
Sun 19/416:25
IAD
-
SEA
1 stop12h 30m
Southwest
Wed 22/409:20
SEA
-
IAD
1 stop11h 20m
Southwest
Deal found 7/2£197
Fri 20/317:55
IAD
-
SEA
Nonstop6h 01m
United Airlines
Tue 24/307:00
SEA
-
IAD
1 stop7h 30m
United Airlines
Deal found 7/2£200

Find 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 7 February 2026.

Round-trip from

£170

One-way from

£95

Popular in

June

Cheapest in

January

Average price

£220
Alaska Airlines
  • Alaska Airlines
  • 7/4-20/4
  • 1 total stop
  • 30h 09m total
  • Washington, D.C. to Seattle
Search Deals
Southwest
  • Southwest
  • 5/3
  • 1 total stop
  • 9h 05m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 11% potential increase in price (£26 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease (£4 potential savings vs. average return price).
Search Deals
Average for round-trip flights in February 2026
Search Deals

Cheapflights Fare Finder

 
Customise your flight search to find flights from Dulles Intl to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 7 February 2026.
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

Dulles Intl

Fly to

Seattle

Route

Depart

Return

Price

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 25/4

17:55-20:53

Nonstop5h 58m

Seattle/Tacoma Intl

Sat 2/5

23:14-07:23

Nonstop5h 09m

£174

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 20/3

07:00-10:03

Nonstop6h 03m

Seattle/Tacoma Intl

Tue 24/3

15:55-23:49

Nonstop4h 54m

£174

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 6/3

07:30-10:29

Nonstop5h 59m

Seattle/Tacoma Intl

Tue 10/3

15:55-23:48

Nonstop4h 53m

£174

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 12/3

17:55-20:56

Nonstop6h 01m

Seattle/Tacoma Intl

Tue 17/3

08:00-16:02

Nonstop5h 02m

£174

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 24/3

07:00-10:03

Nonstop6h 03m

Seattle/Tacoma Intl

Tue 31/3

15:55-23:49

Nonstop4h 54m

£174

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 16/3

07:05-10:05

Nonstop6h 00m

Seattle/Tacoma Intl

Tue 24/3

21:40-05:40

Nonstop5h 00m

£203

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 3/3

07:30-10:29

Nonstop5h 59m

Seattle/Tacoma Intl

Mon 9/3

15:55-23:48

Nonstop4h 53m

£207

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 6/3

07:30-10:29

Nonstop5h 59m

Seattle/Tacoma Intl

Mon 9/3

15:55-23:48

Nonstop4h 53m

£207

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 30/3

19:45-01:40

1 stop8h 55m

Seattle/Tacoma Intl

Wed 8/4

13:25-23:40

1 stop7h 15m

£211

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 5/3

18:20-09:28

1 stop18h 08m

Seattle/Tacoma Intl

Mon 9/3

21:45-05:40

Nonstop4h 55m

£211

Flights are sorted by cheapest return flights first.

Deals found on 5/2

Showing 1-10 of 23 results
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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
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

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?

Use this chart to determine the optimal time to book a return flight from Dulles Intl to Seattle. Price data was last updated on 30 January 2026.

The best time to book flights from Washington, D.C. Dulles Intl Airport to Seattle is 36 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, February is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Seattle (average of £87). Flying from Washington, D.C. Dulles Intl Airport to Seattle in July is currently the most expensive (average of £176). 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?

Find hourly flight availability from Dulles Intl to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 7 February 2026.

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.

  • 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?

    United Airlines and Delta can get you from Washington, D.C. Dulles Intl Airport to Seattle in just under 5h 58m. 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 United Airlines (81%), Copa Airlines (78%) and Ethiopian Air (78%).

  • 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, February is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Seattle (average of £87). Flying from Washington, D.C. Dulles Intl Airport to Seattle in July is currently the most expensive (average of £176). 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
Tacoma
Federal Way
SeaTac

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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.

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.

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