SEA - IAD

$179 Find Cheap Flights from Seattle to Washington Dulles Airport - Compare and Save

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Everything you should know

Cheapest round-trip
$298
Typical prices: $331-$591
Frontier
Sun 9/23Fri 9/28
SEA - IAD • 1 stop
Cheapest non-stop
$345
Typical prices: $334-$596
Alaska Airlines
Mon 9/24Sun 9/30
SEA - IAD • Non-stop
Advice from real travelers
United Economy Plus adds up to 6 inches more legroom than standard economy.
Delta free Wi-Fi helps on this domestic route; Alaska adds Priority Boarding.
Expert advice
+1
Expert advice
+1
Nonstop flights
You can fly direct with Alaska Airlines, United Airlines and Delta. Average duration is 5h 05m
Direct flights
+1
Direct flights
+1
When to book
in advance
Our data shows that travelers who book at least 17 weeks in advance save around 62% compared to booking last minute.
Insights
Insights
When to travel
Cheapest • 19% price drop
Most popular
Good to know
+1
Good to know
+1
Top layover airports
Cheapest • Avg $196 (round-trip)
Shortest trip • 7h 41m (one-way)
Insights
Insights
Start a new search
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We hope you love your trip to Washington, D.C. Dulles Intl Airport!
Flight Deals
Booking Insights
Expert advice
Flight Deals

Cheap Flights from Seattle to Dulles Intl (SEA-IAD)

 
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to Dulles Intl

Mon, Sep 21 - Wed, Sep 30
Frontier Logo
9:45 pm - 6:20 amSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
29h 35m1 stop Las Vegas Harry Reid Intl
Frontier Logo
6:00 am - 9:42 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
30h 42m1 stop Las Vegas Harry Reid Intl
$298Frontier
Tue, Sep 15 - Tue, Sep 22
Frontier Logo
10:57 am - 6:20 amSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
16h 23m1 stop Las Vegas Harry Reid Intl
Frontier Logo
6:00 am - 9:42 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
30h 42m1 stop Las Vegas Harry Reid Intl
$298Frontier
Thu, Sep 24 - Wed, Sep 30
Alaska Airlines Logo
9:35 pm - 5:40 amSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
5h 05mnonstop
Alaska Airlines Logo
9:03 am - 11:39 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
5h 36mnonstop
$345Alaska Airlines
Thu, Sep 24 - Wed, Sep 30
Multiple Airlines Logo
9:35 pm - 5:40 amSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
5h 05mnonstop
Multiple Airlines Logo
6:00 am - 9:42 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
30h 42m1 stop Las Vegas Harry Reid Intl
$348Multiple Airlines
Sat, Oct 10 - Sat, Oct 17
Alaska Airlines Logo
3:56 pm - 11:59 pmSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
5h 03mnonstop
Alaska Airlines Logo
7:02 am - 9:44 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
5h 42mnonstop
$354Alaska Airlines
Wed, Oct 21 - Sat, Oct 24
Multiple Airlines Logo
8:35 pm - 5:50 pmSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
18h 15m1 stop San Diego
Multiple Airlines Logo
6:00 am - 8:58 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
29h 58m1 stop Las Vegas Harry Reid Intl
$354Multiple Airlines
Wed, Oct 14 - Sat, Oct 17
United Airlines Logo
11:14 pm - 7:17 amSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
5h 03mnonstop
United Airlines Logo
5:45 pm - 8:37 pmIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
5h 52mnonstop
$377United Airlines
Sun, Oct 18 - Sat, Oct 24
United Airlines Logo
11:14 pm - 7:17 amSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
5h 03mnonstop
United Airlines Logo
1:05 pm - 3:51 pmIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
5h 46mnonstop
$377United Airlines
Wed, Oct 14 - Sun, Oct 18
Delta Logo
2:50 pm - 10:49 pmSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
4h 59mnonstop
Delta Logo
7:05 am - 9:56 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
5h 51mnonstop
$377Delta
Fri, Oct 9 - Fri, Oct 16
Delta Logo
2:50 pm - 10:49 pmSEA  Seattle/Tacoma Intl-IAD Washington, D.C. Dulles Intl
4h 59mnonstop
Delta Logo
7:05 am - 9:56 amIAD  Washington, D.C. Dulles Intl-SEA Seattle/Tacoma Intl
5h 51mnonstop
$377Delta
Booking Insights

Price, demand and travel trends for Seattle to Washington, D.C. Dulles Intl Airport flights

Use KAYAK data on prices, travel dates, airlines and seasonal trends to compare options and book flights from Seattle to Washington, D.C. Dulles Intl Airport with more confidence.

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

Round-trip flights from Seattle to Washington, D.C. Dulles Intl Airport start at $298. Prices are below average for this route right now, with typical round-trip fares ranging from $331 to $591. The lowest price found in the past 5 days was $298 on Frontier.

What's the cheapest day of the week to fly from Seattle to Washington, D.C. Dulles Intl Airport?

Thursday is the cheapest day of the week to fly from Seattle to Washington, D.C. Dulles Intl Airport, it is 9% cheaper than the average day. Monday is the most expensive day with flight prices 19% higher than average. Based on deals found by KAYAK users in the last 12 months.

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

  • September and October are the cheapest months to fly from Seattle to Washington, D.C. Dulles Intl Airport at $357 round-trip.
  • June ($532) and July ($481) are the most expensive months.
  • The price difference between flying in the cheapest and most expensive months is 49% on average.
This is based on KAYAK aggregated and averaged internal data over the past 12 months.

When are prices from Seattle to Washington, D.C. Dulles Intl Airport the cheapest?

Flights from Seattle to Washington, D.C. Dulles Intl Airport are cheapest 17 weeks before departure. Booking in this window typically costs about 62% less than the average last-minute fare (within 2 weeks of the flight), based on KAYAK data.

Expert advice

Expert advice for your flight from Seattle to Dulles Intl

 
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, Delta 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.

Key details for Seattle to Washington, D.C. Dulles Intl Airport flights

Low season

February

Cheapest flight

$179
Best time to beat the crowds with an average 17% drop in price.
Most popular time to fly with an average 21% increase in price.
Flight from Seattle to Washington, D.C. Dulles Intl Airport

When to book flights from Seattle to Dulles Intl

Are your dates flexible? Find out the best times to travel from Seattle to Dulles Intl based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price

Flights from Seattle to Dulles Intl: the best tips from KAYAK users' own experiences

Insights shared by verified travelers who flew the route from Seattle to Dulles Intl 
SuzetteFlew with Alaska Airlines-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-May 2025
Seatac has gnarly traffic right now, took 35min to get from highway exit to the terminal

Your Seattle to Washington, D.C. Dulles Intl Airport flight questions, answered

Find helpful route details based on KAYAK data, including flight times, airports, airlines and booking questions.

  • Is there a lounge at Seattle-Tacoma International Airport?

    If you want a quiet place where you can relax while you wait for your flight from Seattle to Washington, DC, you can head to the Club at SEA. There are two locations in Concourse A. The one by Gate A12 is open from around 5 am to midnight. The second is above Gate S10 on the mezzanine floor and is open from about 6 am to 7 pm. For about $45, you can enjoy snacks and beverages, including bar service, as well as television and magazines.

  • Will there be inflight entertainment on my trip from Seattle to Washington?

    Many airlines offering flights to Washington Dulles Airport from Seattle provide inflight entertainment. You can check which ones do by expanding the aircraft details in your KAYAK search results. For example, United Airlines has both personal seatback systems as well as streaming options for passengers to enjoy movies, music, and shows.

  • Are there pet relief areas at the airports in Seattle and Washington, DC?

    If you are traveling with your pet or service animal, both airports have pet relief stations with waste disposal bags and trash receptacles. In SEA, there are several pet relief areas throughout the airport, including in the main terminal and in Concourses D, S, and N. In IAD, you can find them by Gates D1 and A32, as well as by the parking lot across from the exit by Baggage Claim 1.

  • Can I rent a car at IAD?

    Many of the major car rental companies offer services at IAD, including Avis, Enterprise, and SIXT. You can catch a shuttle to locations outside Doors 2 and 4 from baggage claim at Curbs 2C or 2D.

  • Which airlines offer extra legroom and free seat selection on Seattle to Washington, D.C. Dulles Intl Airport flights?

    Among airlines operating Seattle to Washington, D.C. Dulles Intl Airport flights:

    • Alaska Airlines: offers free seat selection
    • United Airlines: offers extra legroom; offers free seat selection
    • Delta: offers extra legroom; offers free seat selection
    • American Airlines: offers free seat selection

    Extra legroom and free seat selection availability depends on fare class and route.

  • What airlines are available from Seattle to Washington, D.C. Dulles Intl Airport?

    3 airlines operate flights between Seattle and Washington, D.C. Dulles Intl Airport. The airlines offering nonstop flights on this route include:

    • Alaska Airlines
    • United Airlines
    • Delta

  • Which airports can I use when flying from Seattle to Washington, D.C. Dulles Intl Airport?

    Flights from Seattle to Washington, D.C. Dulles Intl Airport usually depart from Seattle/Tacoma Intl (SEA) and arrive at Washington, D.C. Dulles Intl (IAD).

  • Which airlines include bags at no extra cost on Seattle to Washington, D.C. Dulles Intl Airport flights?

    Here are some options for this route, based on selected ticket types and cabin classes:

    • United Airlines: a cabin bag and a checked bag in Economy Class
    • Delta: a cabin bag and a checked bag in Economy Class
    • Alaska Airlines: a cabin bag and a checked bag in Business Class

    Bag allowance can vary by ticket type, cabin class, route and airline, so travelers should check the fare details before booking.

  • What cabin classes can I book on flights from Seattle to Washington, D.C. Dulles Intl Airport?

    Three cabin classes are available on flights from Seattle to Washington, D.C. Dulles Intl Airport:

    • Economy Class
    • Business Class
    • First Class

  • How much can I save by taking a layover when flying from Seattle to Washington, D.C. Dulles Intl Airport?

    On this route, layover flights are cheaper than nonstop options on average. Layover fares average $196 round-trip via Charlotte Douglas (CLT), compared to $445 for nonstop.

  • What is the standard checked-bag allowance on flights from Seattle to Washington, D.C. Dulles Intl Airport?

    There is no standard. Checked-bag policies vary by airline on this route. Most carriers charge $35–$100 for the first checked bag in economy. Premium fares and elite-status bookings typically include a free checked bag.

  • Which aircraft model is used most often on flights from Seattle to Washington, D.C. Dulles Intl Airport?

    The Boeing 737 family is used most often on this route, operated mainly by American Airlines and United Airlines. Other aircraft seen on the route include Boeing 737-800 Passenger/BBJ2 (winglets) variants.

  • Which airports do connecting flights from Seattle to Washington, D.C. Dulles Intl Airport pass through?

    One-stop flights from Seattle to Washington, D.C. Dulles Intl Airport most commonly connect through:

    • Las Vegas Harry Reid Intl (LAS) - 47% of one-stop connections
    • Denver Intl (DEN) - 40% of one-stop connections
    • Charlotte Douglas (CLT) - 7% of one-stop connections
    • Chicago O'Hare Intl (ORD) - 7% of one-stop connections

    Las Vegas Harry Reid Intl (LAS) handles the largest share of one-stop connections on this route.

  • Can I save money by using flexible dates for flights from Seattle to Washington, D.C. Dulles Intl Airport?

    Yes. Being flexible with your travel dates can save you up to 24% on the Seattle to Washington, D.C. Dulles Intl Airport route. Thursday is the cheapest departure day at $402 round-trip on average, while Monday is the most expensive at $523, a difference of $121. KAYAK's flexible dates feature shows options up to 3 days before and after your selected dates, making it easier to compare nearby fares.

  • How are flight departures from Seattle to Washington, D.C. Dulles Intl Airport spread across the day?

    Morning is the busiest departure period on Seattle to Washington, D.C. Dulles Intl Airport flights, with 40% of flights leaving in that window. Afternoon departures account for 40%, night flights for 20%, and evening flights for 0%.

  • What popular places can I visit in Washington, D.C. Dulles Intl Airport?

    Some of the most popular sights in Washington, D.C. Dulles Intl Airport are Walter E. Washington Convention Center, National Mall and Capital One Arena. These are among the most viewed places in Washington, D.C. Dulles Intl Airport on KAYAK.

  • What are the earliest and latest flights from Seattle to Washington, D.C. Dulles Intl Airport?

    These are the earliest and latest flight times available from Seattle to Washington, D.C. Dulles Intl Airport:

    • Earliest: departs at 8:05 am and lands at 1:10 pm
    • Latest: departs at 11:14 pm and lands at 4:19 am.

    The flight takes about 5h 05m.

  • How expensive are last-minute Seattle to Washington, D.C. Dulles Intl Airport flights?

    Last-minute fares on this route - booked within 2 weeks of departure - run 87% above the route average of $438. Book 17 weeks before departure for the lowest fares.

  • How long is a flight from Seattle to Washington, D.C. Dulles Intl Airport?

    A nonstop flight from Seattle to Washington, D.C. Dulles Intl Airport takes 5h 05m, covering 2,299 miles.

  • Do I need a passport to fly from Seattle to Washington, D.C. Dulles Intl Airport?

    No, a passport is not required for this domestic route, but you will need a real ID-compliant driver's license, a state ID, or another TSA-accepted form of identification.

  • Have flight prices from Seattle to Washington, D.C. Dulles Intl Airport changed much recently?

    Yes. Based on fares seen in the past 5 days, round-trip prices on this route showed a wide range, from about $298 to $1,791. That means the highest observed fare was about 6x higher than the lowest one.

  • How are flight prices from Seattle to Washington, D.C. Dulles Intl Airport looking right now?

    One-way fares from Seattle to Washington, D.C. Dulles Intl Airport are currently lower than usual. Average one-way flight prices are about $203, which is 30% below the typical average for this route.

  • How much time can I save by choosing a different layover airport from Seattle to Washington, D.C. Dulles Intl Airport?

    Flying via Chicago O'Hare Intl (ORD) gives the shortest average 1-stop total travel time at 7h 41m, compared with 8h 44m via Charlotte Douglas (CLT) and 10h 02m via Denver Intl (DEN).

  • What is the time difference between Seattle and Washington, D.C. Dulles Intl Airport?

    Washington, D.C. Dulles Intl Airport is 3 hours ahead of Seattle (Eastern Time vs Pacific Time). Plan for the time shift when scheduling connections or first-day activities.

  • What car rental options are available at Washington, D.C. Dulles Intl Airport (IAD)?

    Washington, D.C. Dulles Intl Airport (IAD) hosts 5 major car rental companies, with daily rates starting from around $24 for economy cars. Top options include:
    · Dollar
    · Budget
    · Hertz
    · Sixt
    · Thrifty

  • How much should I expect to pay for a Seattle to Washington, D.C. Dulles Intl Airport flight?

    Round-trip flights from Seattle to Washington, D.C. Dulles Intl Airport range from $331 to $591, with an average of $438 over the past 12 months. Anything below $331 counts as a good deal.

  • Which airlines offer Wi-Fi on Seattle to Washington, D.C. Dulles Intl Airport flights?

    Two airlines offer in-flight Wi-Fi on Seattle to Washington, D.C. Dulles Intl Airport flights:

    • • Alaska Airlines
    • • Delta

    Pricing varies by airline and fare class. Some plans are included with the ticket or loyalty program; others are paid add-ons priced by flight length.

Your guide to booking Seattle to Washington, D.C. Dulles Intl Airport flights

Get tips on when to book, when to fly and what to know before your trip.
  • If your dates can be flexible, aim for a Thursday departure instead of Monday. On this route, Thursday flights average $402 - about $121 less than Monday (23% savings) based on the last 12 months.
  • For the best chance at a low fare, aim to book around 17 weeks before you fly. On this route, that window historically saves about 62% versus last-minute pricing (KAYAK booking data, last 12 months).
  • If you can choose when to travel, plan your Seattle to Washington, D.C. Dulles Intl Airport trip for September. Fares historically average $357 round-trip in that month - typically $175 less than the most expensive month, which is June (based on the last 12 months).
  • If you have the time, taking a 1-stop flight through Charlotte Douglas Airport (CLT) can be cheaper than flying direct. The cheapest layover option averages $196 round-trip on this route - about $248 less than direct flights (based on the last 12 months).
  • Seattle-Tacoma International Airport (SEA), also called Sea-Tac, is the main airport for the greater Seattle metropolis. It is about 14 miles from downtown Seattle, and Alaska and Delta Airlines use it as a hub. Washington Dulles International Airport (IAD) is the main airport for the Washington DC area, where it is a United Airlines hub, and is located about 42 miles from downtown DC.
  • You could take one of the many non-stop flights from Seattle to Washington Dulles Airport, or you may prefer a flight with one or more stops. For example, Delta flies to IAD with stops in Detroit or New York City, and American Airlines can take you to DC via Chicago and Charlotte.
  • Flights from Washington Dulles Airport to Seattle average about 2,087 lbs. in CO2 emissions per passenger. If you would like to keep that number as low as possible, you could fly Alaska Air’s non-stop service, which ranges from only around 1,216 to 1,461 lbs. in emissions, about 42% to 30% less than the average.
  • You have two public transport options from downtown Seattle to the airport. The Link Light Rail costs about $3 a person, and you can get tickets at the station. The King County Metro Bus also has numerous routes from the city center to the airport for around $3 as well. You can pay the driver in cash, but you need exact change.
  • If you choose to drive and park your car at SEA, there are long-term parking lots at the airport. At the Terminal Direct parking on the 4th floor of the garage, you can walk to the main terminal from this floor for about $42 a day or around $294 a week. You can park on the other floors for around $34 a day or $169 per week.

Prefer to fly direct from Seattle to Washington Dulles Airport?

 
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 direct 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 direct flights

Everything you need to know for your flight from Seattle to Dulles Intl

Information on your arrival and departure airports