$104 Cheap Flights from Washington (IAD) to Seattle (SEA)

  • Plan, book, fly with confidence

  • trending down icon
    Be in the know
    Get alerts if flight prices drop or rise*
  • bex rewards loyalty icon
    Book smarter
    Save up to 30% on select hotels after you book a flight*
  • one key icon
    Earn twice
    Earn your airline miles on top of our OneKeyCash
Find available prices by choosing your travel dates.

Cheap Flights from Washington to Seattle (IAD-SEA)

Prices were available within the past 7 days and start at $104 for one-way flights and $208 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Frontier Airlines
Frontier Airlines
Alaska Airlines
Alaska Airlines
Frontier Airlines
Frontier Airlines
Delta
United
American Airlines

Frequently asked questions

How much does a flight from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) cost?
You can score cheap return tickets from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) starting from $281. Book a seat and take off on your trip. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Alaska Airlines flight leaving IAD on May 15 2025 and touching down at SEA. The price was last updated on April 23 2025 and has not changed since.
What is the cheapest month to fly from IAD to SEA?
The cheapest flights from IAD to SEA are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
Which airlines fly direct from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
Fly straight to Seattle - Tacoma Intl. Airport (SEA). 3 airlines offer direct flights from Washington Dulles Intl. Airport (IAD), including:

  • Delta Air Lines
  • United Airlines
  • Alaska Airlines

What is the cheapest airline that flies from IAD to SEA?
Currently, the cheapest carrier operating one-way flights from IAD to SEA is Alaska Airlines. You can book a seat on this route from $144. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from IAD on May 15 2025. Prices were last updated on April 23 2025 and have not changed since.
How many flights per day from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
When departing from Washington Dulles Intl. Airport (IAD), you can pick from an average of 3 daily nonstop flights to Seattle - Tacoma Intl. Airport (SEA).
What are the most popular departure times for flights from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
More travelers fly between IAD and SEA at 4 PM than at any other point in the day. Rather go when it’s quieter? Consider flying outside peak hours and you’re likely to save on your fare as well.
What day of the week has the most flights from IAD to SEA?
Friday offers the most flights from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA). Consider leaving on this day and you’ll have the best chance of finding a departure that fits your itinerary.
What is the earliest flight from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
The first flight of the day out of Washington Dulles Intl. Airport (IAD) is at around 4:05PM UTC-5. Board this plane and you’ll reach Seattle - Tacoma Intl. Airport (SEA) at approximately 7:06PM UTC-8. The total time in the air is 6h 1m.
How long does it take to fly from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
It usually takes 6 hours and 1 minute to travel the 2,300 mi from IAD to SEA.
What airline has the least delays from IAD to SEA?
With 84% of flights generally landing on time, United Airlines has the best on-time performance for direct flights from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA). To check your flight status and receive notifications if anything changes, head to the Expedia App.
What is the best time to fly from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
To avoid potential delays on the Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) route, aim to travel before 3 PM. Flights after this time are 22% more likely to be canceled.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG’s global flight data platform.
What airports do you fly into for Seattle from Washington Dulles Intl. Airport (IAD)?
Seattle - Tacoma Intl. Airport (SEA) is the only airport in Seattle with direct flights from Washington Dulles Intl. Airport (IAD). Consider the options and find affordable fares on Expedia.
Is it cheaper to buy a plane ticket from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) last-minute?
Holding off until right before your break to book your flight from IAD to SEA generally means paying more. While it’s possible to find some last-minute discounts, they’re not always guaranteed. Keep your travel schedule open for the best chance of landing a bargain.
Is it cheaper to book an IAD to SEA flight and hotel package?
Booking an IAD to SEA flight and hotel package tends to be cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels in one place. Pick from our extensive range of accommodations and then add car rentals, activities and flights to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
In most instances, you can cancel or reschedule your IAD to SEA flight. However, additional charges may apply, especially if your booking was made over 24 hours ago. Double-check your itinerary for the airline’s guidelines and fees on flight changes, or if you need further details, visit our Customer Service portal.
*Available to One Key members.