Find Cheap Flights from Seattle/Tacoma Intl to Washington Dulles Intl (SEA - IAD)

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Good to Know

Low Season:
September
Best time to beat the crowds
2%
expected price decrease
High Season:
December
Most popular time to fly
3%
expected price increase
Average Price:
$476
(avg. price over the last 2 weeks)
Good Deal:
$319
or less (round trip)

When to Book Flights from Seattle/Tacoma Intl to Washington Dulles Intl

Average price per month
Flight prices as travel date approaches
-1 day
-2 days

Top tips for Finding a Cheap Flight

Looking for a cheap flight? 25% of our users found flights on this route for $318 or less.
The cheapest flight from Seattle/Tacoma Intl to Washington Dulles Intl was found 78 days before departure, on average.
Book at least 2 weeks before departure in order to get a below-average price.
Morning departure is around 2% cheaper than an evening flight, on average*.
*Average of the lowest prices shown in KAYAK’s search results for departures within the next 30 days

FAQs for Booking Seattle/Tacoma Intl to Washington Dulles Intl Flights

How long does a flight from Seattle/Tacoma Intl to Washington Dulles Intl take?
An average nonstop flight takes 4h 48m, covering a distance of 2300 miles.
How many flights are there between Seattle/Tacoma Intl and Washington Dulles Intl?
There are 174 (nonstop) flights between Seattle/Tacoma Intl and Washington Dulles Intl per week, averaging 26 per day.
Which airlines provide the cheapest flights from Seattle/Tacoma Intl to Washington Dulles Intl?
In the past 3 days, the cheapest round-trip tickets were found on Frontier ($167), Multiple Airlines ($240) and American Airlines ($323).
Do I need a passport to fly between Seattle/Tacoma Intl and Washington Dulles Intl?
No.
Which airlines fly most frequently between Seattle/Tacoma Intl and Washington Dulles Intl?
United (5 times daily), Avianca (3 times daily), Copa Airlines (3 times daily) are the most frequent flyers on this route.
What’s the cheapest day of the week to fly Seattle/Tacoma Intl to Washington Dulles Intl?
For Seattle/Tacoma Intl to Washington Dulles Intl, Wednesday is the cheapest day to fly on average and Friday is the most expensive. Flying from Washington Dulles Intl back to Seattle/Tacoma Intl, the best deals are generally found on Tuesday, with Sunday being the most expensive.

Book cheap flights from Seattle/Tacoma Intl to Washington Dulles Intl (round-trip)

Airports
Origin
Seattle
$167
only
$167
Destination
Washington
$167
only
$167
Wed, Apr 25
SEA
IAD
14h 41m
Wed, May 2
IAD
SEA
17h 50m
Trip: 8 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33532 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
SFO
MCO
Okay 4.6

On time

Told to get there 3 hours before,checkin opened 2 hours before. Plane was clean,and fairly new, seat most uncomfortable,limited leg room. Total fare plus $150 for luggage , NOT a budget price. First and last time user.

ORD
DEN
Mediocre 2.0

We got delayed because the plane broke down. Everyone else got $100 credit, but I didn't because I booked through Kayak. Could you please give me the credit?

MCO
SFO
Okay 5.6

Flight wasn’t bad for what I paid for. One MUST definitely do his/her homework before flying to be prepared for all of the extra costs, etc... I was glad I did and was prepared with my own food, neck pillow, etc. I didn’t expect much in terms of creature comforts and therefore wasn’t disappointed. There isn’t much space in the cabin, so I was glad to have my 6-year old in between us 2 adults. Crew was pleasant r and professional. Ticket agent was helpful if a bit “assertive”. I probably won’t try to book them for long flights, but for short flights their fine

The tiny space and small seats!

IAD
AUS
Mediocre 2.0

Lots of miscommunication and no help with assisting passengers off plane to rebook Austin to San Diego flight

CVG
RSW
Okay 4.3

The seats don't move so very uncomfortable to try and relax. No free beverages. Bag fees are riduculous.

Tue, Jan 23
SEA
IAD
10h 13m
Tue, Jan 30
IAD
SEA
18h 46m
Trip: 8 days
Overall 0.0 Poor
Based on 0 reviews
Thu, Mar 1
SEA
IAD
7h 24m
Wed, Mar 7
IAD
SEA
10h 16m
Trip: 7 days
7.2GoodShow reviews
Overall 7.2 Good
Based on 27083 reviews
Overall
7.3
Boarding
7.5
Comfort
7.1
Crew
7.8
Entertainment
6.7
Food
6.6
FAT
DFW
Excellent 8.0

Late to Tulsa again.l

PHL
LAX
Mediocre 2.0

American Airlines lied to us that this flight was canceled. They made me go to the ticket counter to book another flight. While standing in line, my husband found out it was not canceled, but they were boarding the plane. The porter that pushed my mother in the wheelchair was able to get our bags checked. No American Airlines employee would help us. They just said to go back to the end of the line. The porter called the gate to have the plane wait for us. American Airlines DISCRIMINATES especially against the elderly!

LAX
NRT
Excellent 8.0

Entertainment was great

Wish the seats could've been a bit more comfortable

DCA
ORD
Good 7.3

Seating is a bit cramped.

DFW
TPA
Okay 4.0

Flight delay, no beverage service

Wed, May 2
SEA
IAD
8h 00m
Wed, May 9
IAD
SEA
14h 39m
Trip: 8 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33532 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
SFO
MCO
Okay 4.6

On time

Told to get there 3 hours before,checkin opened 2 hours before. Plane was clean,and fairly new, seat most uncomfortable,limited leg room. Total fare plus $150 for luggage , NOT a budget price. First and last time user.

AUS
PHX
Excellent 10.0

Everything

Nothing

LAX
MCO
Okay 4.6

Very uncomfortable plane

AUS
ONT
Okay 5.0

The fair was low and boarding was efficient.

The booking process was terrible online. There’s a charge for refreshments, the tray table is tiny, the staff didn’t seem happy, the seats don’t recline at all, they charge for carry ons, no outlet to charge my device.

MCO
SFO
Okay 5.6

Flight wasn’t bad for what I paid for. One MUST definitely do his/her homework before flying to be prepared for all of the extra costs, etc... I was glad I did and was prepared with my own food, neck pillow, etc. I didn’t expect much in terms of creature comforts and therefore wasn’t disappointed. There isn’t much space in the cabin, so I was glad to have my 6-year old in between us 2 adults. Crew was pleasant r and professional. Ticket agent was helpful if a bit “assertive”. I probably won’t try to book them for long flights, but for short flights their fine

The tiny space and small seats!

Wed, Mar 21
SEA
IAD
4h 49m
Thu, Mar 22
IAD
SEA
5h 51m
Trip: 2 days
6.5GoodShow reviews
Overall 6.5 Good
Based on 64 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
SEA
IAD
Mediocre 3.6

Gate crew didn't help much with seating or connecting flights. Staff almost never smiled, and when boarding the plane instead of a, "hello" or "good morning", there were two attendants staring at their phones. They looked up when I greeted first, but seemed put off a touch. They also switched the seating without telling us ahead of time, so my husband and I had to sit in middle seats, apart from each other on our anniversary trip. Very unhelpful and unfriendly when I inquired to change.

SEA
IAD
Excellent 10.0

Rhe food

Custmer Service

SEA
IAD
Good 7.0

Poor internet going. No internet or streaming returning.

Poor internet going. No internet or streaming returning.

SEA
IAD
Excellent 10.0

Awesome

Awesome

SEA
IAD
Good 7.6

Wish the free in flight entertainment was available on the United app for this flight

Wed, Jun 6
SEA
IAD
8h 00m
Tue, Jun 12
IAD
SEA
21h 02m
Trip: 7 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33532 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
LAX
MCO
Okay 4.6

Very uncomfortable plane

MCO
OKC
Okay 4.3

Long lines

AUS
PHX
Excellent 10.0

Everything

Nothing

CVG
RSW
Okay 4.3

The seats don't move so very uncomfortable to try and relax. No free beverages. Bag fees are riduculous.

ORD
DEN
Mediocre 2.0

We got delayed because the plane broke down. Everyone else got $100 credit, but I didn't because I booked through Kayak. Could you please give me the credit?

Tue, Feb 6
SEA
IAD
10h 13m
Wed, Feb 21
IAD
SEA
18h 36m
Trip: 16 days
Overall 0.0 Poor
Based on 0 reviews
Tue, Jul 24
SEA
IAD
4h 49m
Thu, Aug 9
IAD
SEA
11h 15m
Trip: 17 days
6.5GoodShow reviews
Overall 6.5 Good
Based on 64 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
SEA
IAD
Okay 5.0

Cramped seatting, minimal food or beverage options and we were invited to provide our own entertainment. Pretty typical flight for ten or fifteen years ago. The crew was extremely pleasant. Very surprising and maybe the only saving grace.

The airline is clearly trying to maximize profits by squeezing any comfort from the plane while still charging ludicrous amounts. Good for them. That's their free market choice. But do not then be startled that everyone is angry before, during, and after your flights. In the long run that's how you shed customers.

SEA
IAD
Okay 4.6

The flight was smooth

The air hosts were in friendly and didn't say goodbye. The cabin was improperly pressurized and hurt my ears going up and landing. My ear is still popping.

SEA
IAD
Excellent 10.0

Rhe food

Custmer Service

SEA
IAD
Excellent 10.0

Awesome

Awesome

SEA
IAD
Okay 4.6

Extremely tight fit. Much much smaller than other major airlines . Both flight attendants were rude. Not looking dorward to flying back home with united Option to rent movies is really nice though. Helps the flight go by faster .

Mon, Mar 5
SEA
IAD
4h 50m
Wed, Mar 7
IAD
SEA
5h 56m
Trip: 3 days
Overall 0.0 Poor
Based on 0 reviews
Wed, Jan 31
SEA
IAD
4h 59m
Sat, Feb 3
IAD
SEA
5h 56m
Trip: 4 days
Overall 0.0 Poor
Based on 0 reviews
Wed, Jul 11
SEA
IAD
8h 25m
Mon, Jul 16
IAD
SEA
14h 50m
Trip: 6 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33532 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
ORD
DEN
Mediocre 2.0

We got delayed because the plane broke down. Everyone else got $100 credit, but I didn't because I booked through Kayak. Could you please give me the credit?

CLT
MCO
Excellent 10.0

Friendliness of staff

No water passed out

MCO
OKC
Okay 4.3

Long lines

AUS
ONT
Okay 5.0

The fair was low and boarding was efficient.

The booking process was terrible online. There’s a charge for refreshments, the tray table is tiny, the staff didn’t seem happy, the seats don’t recline at all, they charge for carry ons, no outlet to charge my device.

CVG
RSW
Okay 4.3

The seats don't move so very uncomfortable to try and relax. No free beverages. Bag fees are riduculous.

Fri, Jun 1
SEA
IAD
8h 00m
Wed, Jun 6
IAD
SEA
10h 34m
Trip: 6 days
Overall 0.0 Poor
Based on 0 reviews
Thu, Jul 5
SEA
IAD
4h 48m
Tue, Jul 10
IAD
SEA
17h 50m
Trip: 6 days
Overall 0.0 Poor
Based on 0 reviews
Fri, Mar 30
SEA
IAD
4h 48m
Mon, Apr 9
IAD
SEA
8h 32m
Trip: 11 days
Overall 0.0 Poor
Based on 0 reviews
Fri, May 25
SEA
IAD
5h 00m
Mon, May 28
IAD
SEA
10h 34m
Trip: 4 days
Overall 0.0 Poor
Based on 0 reviews
Show more results
*
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The fares displayed include all taxes and fees for economy class travel and were found by the provider in the last 72 hours. Seats are limited and may not be available on all flights and days. Fares are subject to change and may not be available on all flights or dates of travel. Some carriers charge additional fees for extra checked bags. Please check the carriers' sites.

Seattle/Tacoma Intl to Washington Dulles Intl Flight Information

Avg. Flight Duration 5h 23m
Flights Arrive in Washington Dulles Intl
Flights Depart from Seattle/Tacoma Intl
Flight Price $167
Distance 2300 miles
Airlines Frontier, American Airlines, United