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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £110

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 24/5. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
5 May — 12 May1
1 adult

Cheap 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 30 April 2025.

Round-trip from

£192

One-way from

£110

Popular in

December

Cheapest in

February

Average price

£289
Hawaiian Airlines
  • Hawaiian Airlines
  • 27/5-28/5
  • Nonstop
  • 10h 46m total
  • Washington, D.C. to Seattle
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United Airlines
  • United Airlines
  • 24/5
  • Nonstop
  • 5h 53m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 0% potential increase in price (£2 potential increase over avg. return price).
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Cheapest flight prices on average. 2% potential price decrease (£6 potential savings vs. average return price).
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Average for round-trip flights in April 2025
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Find flight deals from Dulles Intl to Seattle

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 30 April 2025.

Tue 27/506:48IAD - SEA
1 stop7h 44mUnited Airlines
Tue 3/612:44SEA - IAD
1 stop7h 06mUnited Airlines
Deal found 29/4£192
Sat 24/518:15IAD - SEA
Nonstop5h 45mAlaska Airlines
Tue 27/516:00SEA - IAD
Nonstop4h 59mAlaska Airlines
Deal found 29/4£199
Sat 31/507:45IAD - SEA
Nonstop5h 48mDelta
Sun 1/621:50SEA - IAD
Nonstop5h 02mDelta
Deal found 29/4£214
Thu 15/512:49IAD - SEA
1 stop25h 56mSun Country Air
Wed 21/518:33SEA - IAD
1 stop14h 14mSun Country Air
Deal found 28/4£239
Tue 24/618:13IAD - SEA
Nonstop5h 47mHawaiian Airlines
Tue 24/623:30SEA - IAD
Nonstop4h 57mHawaiian Airlines
Deal found 29/4£266
Tue 8/717:35IAD - SEA
1 stop10h 40mSouthwest
Wed 16/708:50SEA - IAD
2 stops10h 55mSouthwest
Deal found 28/4£270
Fri 13/607:30IAD - SEA
1 stop9h 41mMultiple Airlines
Fri 20/618:59SEA - IAD
1 stop8h 51mMultiple Airlines
Deal found 29/4£305
Fri 13/607:30IAD - SEA
1 stop9h 41mFrontier
Fri 20/615:11SEA - IAD
1 stop12h 19mFrontier
Deal found 29/4£355

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 30 April 2025.
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

Tue 27/5

06:48-11:32

1 stop7h 44m

Seattle/Tacoma Intl

Tue 3/6

12:44-22:50

1 stop7h 06m

£192

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 24/5

18:15-21:00

Nonstop5h 45m

Seattle/Tacoma Intl

Tue 27/5

16:00-23:59

Nonstop4h 59m

£199

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 31/5

07:45-10:33

Nonstop5h 48m

Seattle/Tacoma Intl

Sun 1/6

21:50-05:52

Nonstop5h 02m

£214

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 15/5

12:49-11:45

1 stop25h 56m

Seattle/Tacoma Intl

Wed 21/5

18:33-11:47

1 stop14h 14m

£239

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 24/6

18:13-21:00

Nonstop5h 47m

Seattle/Tacoma Intl

Tue 24/6

23:30-07:27

Nonstop4h 57m

£266

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 8/7

17:35-01:15

1 stop10h 40m

Seattle/Tacoma Intl

Wed 16/7

08:50-22:45

2 stops10h 55m

£270

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 13/6

07:30-14:11

1 stop9h 41m

Seattle/Tacoma Intl

Fri 20/6

18:59-06:50

1 stop8h 51m

£305

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 13/6

07:30-14:11

1 stop9h 41m

Seattle/Tacoma Intl

Fri 20/6

15:11-06:30

1 stop12h 19m

£355

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 24/5

17:48-20:41

Nonstop5h 53m

£110

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 17/6

18:13-21:00

Nonstop5h 47m

£111

Flights are sorted by cheapest return flights first.

Deals found on 28/4

Showing 1-10 of 15 results
1
2

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 25 April 2025.

The best time to book flights from Washington, D.C. Dulles Intl Airport to Seattle is 40 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 £622). Flying from Washington, D.C. Dulles Intl Airport to Seattle in July is currently the most expensive (average of £946). 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 30 April 2025.

When flying from Washington, D.C. Dulles Intl Airport to Seattle, the time of day you fly usually plays a role in the price. Save by searching for a flight in the morning, which can drop the price by up to 13% versus a flight at midday.

Weekly flight availability from Washington, D.C. Dulles Intl Airport to Seattle

Explore weekly flight availability from Dulles Intl to Seattle. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 30 April 2025.

The most flights from IAD to SEA are scheduled on a Tuesday (27 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (2 on average).

Rainfall in Seattle by month

Plan your trip to Seattle by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Seattle ranges from 18.0 - 168.0 inches per month. November is typically the wettest month, when rainfall can reach 168.0 mm. July is typically the driest time to visit Seattle when rainfall is around 18.0 mm.

Temperature in Seattle by month

Plan your trip to Seattle by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Seattle, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 19.0 C. Travellers hoping to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 5.0 C).

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Seattle. Reviews last updated 30 April 2025.
See what other customers who have flown with Alaska Airlines, Southwest and Delta from Washington, D.C. to Seattle have to say. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very Good
9,961 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Southwest
8.0
Very Good
4,295 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very Good
7,929 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Hawaiian Airlines
7.9
Good
2,405 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,696 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

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.

  • What are the cheapest airlines flying from Washington, D.C. Dulles Intl Airport to Seattle round-trip?

    Our cheapest airline available from Washington, D.C. Dulles Intl Airport to Seattle is Hawaiian Airlines. Our recent data shows that you can find tickets from as low as £192 on this airline. Additional options worth looking into are Alaska Airlines and Delta, starting at £202 and £207 round-trip. Hawaiian Airlines is 37% cheaper than the average price of flights available within the next 90 days to this destination.

  • What are the cheapest airlines to fly from Washington, D.C. Dulles Intl Airport to Seattle one-way?

    The cheapest airline one-way is United Airlines, with whom users have recently found tickets for as low as £110. However, be on the lookout for offers from Hawaiian Airlines and Sun Country Air, as they are both options that can get you from Washington, D.C. Dulles Intl Airport to Seattle for a low price.

  • 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 Iberia (100%), Singapore Airlines (100%) and Japan Airlines (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 £622). Flying from Washington, D.C. Dulles Intl Airport to Seattle in July is currently the most expensive (average of £946). 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 Washington, D.C. Dulles Intl Airport?

Book flights to Washington, D.C. Dulles Intl Airport if you plan to visit one of these locations
Tacoma
Leavenworth
Bothell

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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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