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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £117

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 20/2. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
26 Jan — 2 Feb1
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 21 January 2025.

Round-trip from

£225

One-way from

£117

Popular in

December

Cheapest in

February

Average price

£290
Delta
  • Delta
  • 11/3-18/3
  • Nonstop
  • 11h 06m total
  • Washington, D.C. to Seattle
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United Airlines
  • United Airlines
  • 20/2
  • Nonstop
  • 6h 00m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 2% potential increase in price (£5 potential increase over avg. return price).
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Cheapest flight prices on average. 2% potential price decrease (£7 potential savings vs. average return price).
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Average for round-trip flights in January 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 21 January 2025.

Tue 11/307:43IAD - SEA
Nonstop6h 02mDelta
Tue 18/322:15SEA - IAD
Nonstop5h 04mDelta
Deal found 21/1£225
Thu 20/207:00IAD - SEA
Nonstop5h 56mAlaska Airlines
Fri 28/221:40SEA - IAD
Nonstop4h 52mAlaska Airlines
Deal found 21/1£233
Wed 12/217:30IAD - SEA
Nonstop6h 00mUnited Airlines
Thu 20/207:15SEA - IAD
1 stop10h 48mUnited Airlines
Deal found 21/1£234
Wed 25/612:40IAD - SEA
1 stop13h 04mSun Country Air
Wed 2/723:59SEA - IAD
1 stop8h 44mSun Country Air
Deal found 21/1£293
Tue 11/315:40IAD - SEA
1 stop11h 05mSouthwest
Tue 18/306:40SEA - IAD
2 stops13h 45mSouthwest
Deal found 21/1£303

Find flights from Dulles Intl to Seattle within your budget

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 21 January 2025.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 11/3

07:43-10:45

Nonstop6h 02m

Seattle/Tacoma Intl

Tue 18/3

22:15-06:19

Nonstop5h 04m

£225

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 20/2

07:00-09:56

Nonstop5h 56m

Seattle/Tacoma Intl

Mon 24/2

21:40-05:32

Nonstop4h 52m

£233

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 12/2

17:30-20:30

Nonstop6h 00m

Seattle/Tacoma Intl

Thu 20/2

07:15-21:03

1 stop10h 48m

£234

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 8/3

19:50-00:50

1 stop8h 00m

Seattle/Tacoma Intl

Sun 9/3

11:00-00:55

1 stop10h 55m

£290

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 25/6

12:40-22:44

1 stop13h 04m

Seattle/Tacoma Intl

Tue 1/7

18:40-11:43

1 stop14h 03m

£293

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 20/2

17:19-20:19

Nonstop6h 00m

£117

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 2/4

07:00-13:17

1 stop9h 17m

£120

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 18/3

06:09-16:05

1 stop12h 56m

£128

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 21/4

11:37-17:19

1 stop8h 42m

£145

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 5/4

19:50-00:50

1 stop8h 00m

£146

Flights are sorted by cheapest return flights first.

Deals found on 21/1

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.

Travel insights for flights from Dulles Intl to Seattle

Get recent, data-driven insights about flights from Dulles Intl to Seattle including ideal travel times, pricing trends, and more.

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 17 January 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 21 January 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 31% 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 21 January 2025.

The most flights from IAD to SEA are scheduled on a Tuesday (14 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (12 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 21 January 2025.
See what other customers who have flown with Delta, United Airlines and Southwest 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.
Southwest
8.1
Very Good
4,662 reviews
Check prices

Food

7.2

Crew

8.7

Comfort

8.1

Entertainment

7.7

Overall

8.1

Boarding

8.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Southwest
8.1
Very Good
4,662 reviews
Southwest
8.1
Very Good
4,662 reviews
Check prices

Food

7.2

Crew

8.7

Comfort

8.1

Entertainment

7.7

Overall

8.1

Boarding

8.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Alaska Airlines
8.0
Very Good
9,706 reviews
Southwest
8.1
Very Good
4,662 reviews
Check prices

Food

7.2

Crew

8.7

Comfort

8.1

Entertainment

7.7

Overall

8.1

Boarding

8.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Delta
8.0
Very Good
8,521 reviews
Southwest
8.1
Very Good
4,662 reviews
Check prices

Food

7.2

Crew

8.7

Comfort

8.1

Entertainment

7.7

Overall

8.1

Boarding

8.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

United Airlines
7.4
Good
8,984 reviews
Southwest
8.1
Very Good
4,662 reviews
Check prices

Food

7.2

Crew

8.7

Comfort

8.1

Entertainment

7.7

Overall

8.1

Boarding

8.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Sun Country Air
7.0
Good
386 reviews
Southwest
8.1
Very Good
4,662 reviews
Check prices

Food

7.2

Crew

8.7

Comfort

8.1

Entertainment

7.7

Overall

8.1

Boarding

8.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

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 13 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 Delta. Our recent data shows that you can find tickets from as low as £225 on this airline. Additional options worth looking into are Alaska Airlines and United Airlines, starting at £233 and £234 round-trip. Delta is 32% 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 £117. However, be on the lookout for offers from Alaska Airlines and Delta, 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 Air Tahiti Nui (93%), Hawaiian Airlines (90%) and Qatar Airways (89%).

  • 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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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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