SEA - IAD

C$ 243 Find Cheap Flights from Seattle to Washington Dulles Airport – Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Seattle to Washington, D.C. departing on 18/9. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

Save 20% or more on flights. Compare deals from all over the web.

Never overpay with our price tracking tools.

Filter searches by price, airline and more to find your best flights.

Everything you should know

Cheapest round-trip
C$ 400
Typical prices: C$ 414-C$ 822
Alaska Airlines
Mon 14/9Sat 26/9
SEA - IAD • Direct
Cheapest one-way flights
C$ 243
Typical prices: C$ 251-C$ 615
United Airlines
Fri 18/9
SEA - IAD • 1 stop
Advice from real travellers
AI-powered summary based on content written by travel experts and KAYAK users. AI can make mistakes.
United Economy Plus adds up to 15 cm more legroom than standard economy.
Alaska's 20-minute baggage guarantee offers compensation if checked bags are late.
Expert advice
Expert advice
+1
+1
Expert advice
Expert advice
+1
Top airlines
Cheapest • from C$ 400 (round-trip)
Best reviews • 7.8 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Direct flights
You can fly direct with Alaska Airlines, Delta, and United Airlines. Average duration is 5h 03m
Direct flights
Direct flights
+1
+1
Direct flights
Direct flights
+1
When to book
in advance
Our data shows that travellers who book at least 4 weeks in advance save around 52% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 30% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
KAYAK searches hundreds of sites at once to find you the best travel deals.
We hope you love your trip to Washington, D.C.!
Flight Deals
Booking Insights
Expert advice
Flight Deals

Cheap Flights from Seattle to Washington, D.C. (SEA-IAD)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle to Washington, D.C. that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to Washington, D.C.

Mon, 14 Sep - Sat, 26 Sep
Alaska Airlines Logo
9:35 p.m. - 5:40 a.m.
SEA
-
IAD
5h 05mdirect
Alaska Airlines Logo
9:03 a.m. - 11:39 a.m.
IAD
-
SEA
5h 36mdirect
C$ 400Alaska Airlines
Thu, 17 Sep - Tue, 22 Sep
Alaska Airlines Logo
3:56 p.m. - 11:59 p.m.
SEA
-
IAD
5h 03mdirect
Alaska Airlines Logo
7:00 a.m. - 9:37 a.m.
IAD
-
SEA
5h 37mdirect
C$ 400Alaska Airlines
Tue, 15 Sep - Tue, 22 Sep
Delta Logo
2:52 p.m. - 10:56 p.m.
SEA
-
IAD
5h 04mdirect
Delta Logo
7:25 a.m. - 10:05 a.m.
IAD
-
SEA
5h 40mdirect
C$ 400Delta
Wed, 16 Sep - Wed, 23 Sep
Delta Logo
2:52 p.m. - 10:56 p.m.
SEA
-
IAD
5h 04mdirect
Delta Logo
7:25 a.m. - 10:05 a.m.
IAD
-
SEA
5h 40mdirect
C$ 400Delta
Mon, 14 Sep - Wed, 23 Sep
Alaska Airlines Logo
9:35 p.m. - 5:40 a.m.
SEA
-
IAD
5h 05mdirect
Alaska Airlines Logo
7:00 a.m. - 9:37 a.m.
IAD
-
SEA
5h 37mdirect
C$ 400Alaska Airlines
Wed, 16 Sep - Wed, 23 Sep
Alaska Airlines Logo
3:56 p.m. - 11:59 p.m.
SEA
-
IAD
5h 03mdirect
Alaska Airlines Logo
5:57 p.m. - 8:44 p.m.
IAD
-
SEA
5h 47mdirect
C$ 400Alaska Airlines
Mon, 14 Sep - Fri, 25 Sep
Alaska Airlines Logo
9:35 p.m. - 5:40 a.m.
SEA
-
IAD
5h 05mdirect
Alaska Airlines Logo
5:57 p.m. - 8:44 p.m.
IAD
-
SEA
5h 47mdirect
C$ 400Alaska Airlines
Booking Insights

KAYAK's insights & trends for Seattle to Washington, D.C. flights

Get data-powered insights and trends into flights from Seattle to Washington, D.C. to help you find the cheapest flights, the best time to fly and much more.

How much is a round-trip flight from Seattle to Washington, D.C. Dulles Intl Airport?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Seattle to Washington, D.C. Dulles Intl Airport departing in September.

Flight prices are below average for this route right now.

Flights to Washington, D.C. Dulles Intl Airport from Seattle usually cost between C$ 498 and C$ 817 in September.
The lowest price found in the past 5 days was C$ 405 on United Airlines (25 Sep–26 Sep).

What’s the cheapest day of the week to fly from Seattle to Washington Dulles Airport?

The average price of all round-trip flights from Seattle to Washington, D.C. Dulles Intl Airport clicked on KAYAK for each day over the last 12 months.

If your flying dates are flexible, you should consider flying to Washington Dulles Airport on a Thursday, as we generally find the cheapest rates on that day for this route. On the other hand, Saturday is the most expensive day to fly from Seattle to Washington Dulles Airport. For your return ticket, we recommend flying on a Thursday and avoiding Fridays for the best deals.

What is the cheapest month to fly from Seattle to Washington, D.C. Dulles Intl Airport?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Seattle to Washington, D.C. Dulles Intl Airport, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Seattle to Washington, D.C. Dulles Intl Airport is February, where tickets cost C$ 433 (return) on average. On the other hand, the most expensive months are January and July, where the average cost of round-trip tickets is C$ 935 and C$ 687 respectively.

How far in advance should I book a flight from Seattle to Washington, D.C. Dulles Intl Airport?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Seattle to Washington, D.C. Dulles Intl Airport, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Seattle to Washington, D.C. Dulles Intl Airport, you should book around 4 weeks before departure, which saves you about 52% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 23 weeks before departure.

Expert advice

Expert advice for your flight from Seattle to Washington, D.C.

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Harriet Baskas

Harriet Baskas

Expert on Alaska Airlines and SEA

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Stefanie Waldek

Stefanie Waldek

Expert on United Airlines and IAD

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Good to know

Low season

January

Cheapest flight

C$ 243
Best time to beat the crowds but there is an average 51% increase in price.
Most popular time to fly (6% more expensive on average)
Flight from Seattle to Washington Dulles Airport

When to book flights from Seattle to Washington, D.C.

Are your dates flexible? Find out the best times to travel from Seattle to Washington, D.C. based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

Flights from Seattle to Washington, D.C.: the best tips from KAYAK users' own experiences

Insights shared by verified travellers who flew the route from Seattle to Washington, D.C. 
SuzetteFlew with Alaska Airlines
SEA
-
IAD
May 2025
Take a shower before arriving at airport and don't wear perfume at all! Pack bags tight, so boarding is smooth and quick.
DanielFlew with Alaska Airlines
SEA
-
IAD
May 2025
Seatac has gnarly traffic right now, took 35min to get from highway exit to the terminal

FAQs for booking Seattle to Washington Dulles Airport flights

  • What is the cheapest flight from Seattle to Washington, D.C. Dulles Intl Airport?

    In the last 5 days, the lowest price for a flight from Seattle to Washington, D.C. Dulles Intl Airport was C$ 243 for a one-way ticket and C$ 400 for a round-trip.

  • Which airlines offer Wi-Fi service onboard planes from Seattle to Washington Dulles Airport?

    All the following airlines offer inflight Wi-Fi service on the Seattle to Washington Dulles Airport flight route: Alaska Airlines, Delta, JetBlue, American Airlines, Hawaiian Airlines, Lufthansa, and United Airlines.

  • Which aircraft models fly most regularly from Seattle to Washington Dulles Airport?

    The Boeing 737 is the aircraft model that flies most regularly on the Seattle to Washington Dulles Airport flight route.

  • Which airline alliances offer flights from Seattle to Washington Dulles Airport?

    oneworld is the only airline alliance operating flights between Seattle and Washington Dulles Airport.

  • On which days can I fly direct from Seattle to Washington Dulles Airport?

    There are direct flights from Seattle to Washington Dulles Airport on a daily basis.

  • How does KAYAK find such low prices on flights from Seattle to Washington Dulles Airport?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Seattle to Washington Dulles Airport.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Seattle to Washington Dulles Airport?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Washington Dulles Airport from Seattle is likely to change within 7 days, so travellers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Seattle to Washington Dulles Airport?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Washington Dulles Airport with an airline and back to Seattle with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Seattle to Washington Dulles Airport?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Washington Dulles Airport from Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Seattle to Washington, D.C. Dulles Intl Airport

  • Looking for a cheap flight? 25% of our users found flights on this route for C$ 532 or less round-trip.

Prefer to fly direct from Seattle to Washington Dulles Airport?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Seattle/Tacoma Intl to Washington, D.C. Dulles Intl.
Find which airlines fly direct from Seattle/Tacoma Intl Airport to Washington, D.C. Dulles Intl Airport, which days they fly and book direct flights.

Direct departures

Seattle/Tacoma Intl to Washington, D.C. Dulles Intl

Monday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Tuesday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Wednesday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Thursday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Friday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Saturday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Sunday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

See more nonstop flights

Direct returns

Washington, D.C. Dulles Intl to Seattle/Tacoma Intl

Monday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Tuesday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Wednesday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Thursday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Friday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Saturday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

Sunday

Alaska Airlines,Delta,United Airlines

Alaska Airlines,Delta, +1 more

See more nonstop flights

Reviews of the top airline flying from Seattle to Washington, D.C.

 
See real verified KAYAK customer reviews for airlines flying from Seattle to Washington, D.C.. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Seattle to Washington, D.C.? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.8
Hawaiian AirlinesOverall score based on 2820 reviews
7.7Comfort
6.9Food
8.5Crew
7.1Entertainment
8.0Boarding
Airline reviews

The crew at Hawaiian Airlines was fantastic. Kind and hard working. The pilots were great with giving us all the updates to make sure we were informed.

10.0 ExcellentAnastasia, Dec 2025
SEA - HNL
Read more Hawaiian Airlines reviews

The crew at Hawaiian Airlines was fantastic. Kind and hard working. The pilots were great with giving us all the updates to make sure we were informed.

Flight scheduled to take off at 5.55pm but it did not take off until 7pm due to some food delivery delay.

The crew was quite good, they came by often with drinks or to collect trash. But what wasn't nice was the flight was over weigh and several people had to be rebooked. I was questioned whether I should have a seat when I was getting to it. The in-flight entertainment kept buffering and interrupting. And the route took the airplane through high winds which caused us a longer flight

Wasn’t on the flight due to Alaska cancellation…also after all the rerouting, I was going to be on a later flight that left SFO at 7:47pm, which meant an almost 6 hour layover. That same Hawaiian flight was delayed for another 2hours.

Flight was smooth and comfortable. We were able to check a bag at counter due to full flight and boarded with an earlier group. We were there very early and didn’t hear the gate change just noticed our flight was no longer displayed st the gate. There were two other flights with gate shuffles - may be unavoidable but not desirable. First time I had to print my own luggage tag and attach at arrival. Not a fan of that process.

I received an email from Kayak with confirmation number for Hawaiian and another for Alaska. I received emails from Kayak for both my outbound and return flight to say "time to check in." Despite trying each number (Hawaiian and Alaska), I could not check in for outbound or return. It was then confusing at the airport - I hda "no place to go" to figure out how to check in. All the kiosks are marked "scan bag,etc." I wandered around with no agent to talk to. That was a bit stressful. Either Kayak, or airline, needed better communication on what to expect and to do.

Flight got delayed and it was very inconvenient . Had to come with another carrier. Had to spend one more night in San Francisco.

Liked the crew and cleanliness. Terrible comfort (seats did not recline and located next to 3 bathrooms). Did not like the hidden fees, that now there is an additional fee to get a seat.

The departure gate was changed from C1 to B18 but it was never announced at the C1 gate nor did I receive any email or text message or phone call about the gate change. I was in a window seat. In the other two seats next to me were Mr. Rotund and Ms. Rotunda, a youngish couple. Just the two of them should have booked three seats. I was smashed up against the wall and window for five hours. Overall, I'd say my flight sucked. Wouldn't you?

Flight delays, another inconvenienced passenger, and crew serving food and drinks with hair not tied (really very messy - made me apprehensive taking any uncovered food or drinks)

Everything you need to know for your flight from Seattle to Washington, D.C.

Information on your arrival and departure airports