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

Search hundreds of travel sites at once for deals on flights to Washington Dulles Intl

Sat 11/18
Anytime
Sat 11/25
Economy
Compare vs. KAYAK |
Multi-City

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:
$471
(avg. price over the last 2 weeks)
Good Deal:
$309
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

When looking for a cheap flight, consider that 25% of our users selected a flight on this route for $309 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 20% 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 244 (nonstop) flights between Seattle/Tacoma Intl and Washington Dulles Intl per week, averaging 33 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 Multiple Airlines ($241), Frontier ($290) and Alaska Airlines ($337).
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 (6 times daily), Alaska Airlines (4 times daily), Lufthansa (4 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 Saturday is the most expensive. Flying from Washington Dulles Intl back to Seattle/Tacoma Intl, the best deals are generally found on Tuesday, with Wednesday being the most expensive.

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

Airports
Origin
Seattle
$241
only
$241
Destination
Washington
$241
only
$241
Wed, Nov 29
SEA
IAD
10h 20m
Thu, Nov 30
IAD
SEA
29h 30m
Trip: 2 days
Overall 0.0 Poor
Based on 0 reviews
Mon, Apr 23
SEA
IAD
8h 02m
Sat, May 5
IAD
SEA
14h 39m
Trip: 13 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 32923 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
MIA
ISP
Excellent 8.5

The terminal was empty. Plenty of seats. Boarding doesn't take long. Arrival at ISP is nice because it is small and empty.

PHL
MIA
Excellent 10.0

Same as all the other airlines in my opinion. Just way more afreoadable.

LGA
MIA
Mediocre 3.6

Flight Very late , when departure already at night Uncomfortable seats $45 for a bag and I have drop it off myself after pay

FSD
DEN
Okay 4.6

The scheduled plane had a mechanical problem so we deplaned for alternative plan. It took six long hours to get another plane in. Meantime passengers stood in line for hours to make other arrangements. It would have been appropriate for the airline to call in extra staff to help stranded passengers. We missed the scheduled connecting flight and a tour. We got in at 1:00 am, 12 hours later than planned. We had meetings next day and were very tired because we got in so late

PBI
ISP
Mediocre 2.0

Was unable to make it

Thu, Nov 30
SEA
IAD
4h 56m
Sun, Dec 10
IAD
SEA
6h 05m
Trip: 11 days
8.7ExcellentShow reviews
Overall 8.7 Excellent
Based on 36 reviews
Overall
8.6
Boarding
8.7
Comfort
8.4
Crew
8.9
Entertainment
7.8
Food
8.0
SEA
IAD
Excellent 10.0

I loved the free chat and free entertainment! It made such a long flight go so much better and goodbyes and travel easier knowing that I could communicate on the go! For someone with social anxiety, being able to talk to loved ones when I was going through things was the best experience ever! Thank you so much!

PHX
SEA
Excellent 10.0

Excellent Crew - I flew standby, so have great gate agents and flight attendants makes all the difference when you’re hoping for a seat. In flight they are professional and personable and keep you up to date on what you need to know! Plus, I’m always happy when my flights have USB ports so I’m fully charged when I deplane.

I always want more leg room or a little more room under the seat in front of me. But I didn’t upgrade for a roomier seat and there was more than enough overhead space, so truly can’t complain about it!

SEA
IAD
Good 6.0

Wifi didn't work. Very dissappointing.

SEA
IAD
Excellent 10.0

The staff was really friendly, easy boarding, great fast baggage claim. overall great!

SEA
IAD
Excellent 9.3

Alaska Airlines had a very comfortable flight with great attendants and power to charge all your devices.

The wifi service was really poor. I paid 49.99 for Gogo and I got the service of less than a 56.k modem.

Fri, Mar 2
SEA
IAD
19h 35m
Sun, Mar 4
IAD
SEA
29h 35m
Trip: 3 days
Overall 0.0 Poor
Based on 0 reviews
Tue, Jan 23
SEA
IAD
10h 15m
Fri, Jan 26
IAD
SEA
18h 34m
Trip: 4 days
Overall 0.0 Poor
Based on 0 reviews
Wed, Apr 4
SEA
IAD
5h 00m
Tue, Apr 10
IAD
SEA
5h 55m
Trip: 7 days
8.7ExcellentShow reviews
Overall 8.7 Excellent
Based on 36 reviews
Overall
8.6
Boarding
8.7
Comfort
8.4
Crew
8.9
Entertainment
7.8
Food
8.0
SEA
IAD
Excellent 10.0

The staff was really friendly, easy boarding, great fast baggage claim. overall great!

SEA
IAD
Excellent 10.0

Flight had open seats in fact I had a whole row to myself. Plane was clean and new, it even had plug-ins for every seat for charging devices. WiFi was was overpriced but they had movies you could rent and some free. Flights were on time.

SEA
LAX
Excellent 10.0

Great service for an affordable price!

PHX
SEA
Excellent 10.0

Excellent Crew - I flew standby, so have great gate agents and flight attendants makes all the difference when you’re hoping for a seat. In flight they are professional and personable and keep you up to date on what you need to know! Plus, I’m always happy when my flights have USB ports so I’m fully charged when I deplane.

I always want more leg room or a little more room under the seat in front of me. But I didn’t upgrade for a roomier seat and there was more than enough overhead space, so truly can’t complain about it!

SJC
SEA
Good 6.0

Airplane was dirty upon boarding - food and miscellaneous remnants on the seats and floor, used trash bag in the seat back in front of me

Wed, Feb 14
SEA
IAD
14h 49m
Mon, Feb 19
IAD
SEA
5h 39m
Trip: 6 days
Overall 0.0 Poor
Based on 0 reviews
Tue, May 1
SEA
IAD
5h 00m
Tue, May 8
IAD
SEA
5h 55m
Trip: 8 days
8.7ExcellentShow reviews
Overall 8.7 Excellent
Based on 36 reviews
Overall
8.6
Boarding
8.7
Comfort
8.4
Crew
8.9
Entertainment
7.8
Food
8.0
SEA
IAD
Excellent 9.3

Alaska Airlines had a very comfortable flight with great attendants and power to charge all your devices.

The wifi service was really poor. I paid 49.99 for Gogo and I got the service of less than a 56.k modem.

PHX
SEA
Excellent 10.0

Excellent Crew - I flew standby, so have great gate agents and flight attendants makes all the difference when you’re hoping for a seat. In flight they are professional and personable and keep you up to date on what you need to know! Plus, I’m always happy when my flights have USB ports so I’m fully charged when I deplane.

I always want more leg room or a little more room under the seat in front of me. But I didn’t upgrade for a roomier seat and there was more than enough overhead space, so truly can’t complain about it!

SEA
IAD
Good 6.0

Wifi didn't work. Very dissappointing.

SEA
IAD
Excellent 8.3

Friendly and calm professionals in the "assistance" line. The ticket kiosk did not recognize my confirmation number or name so I was instructed to wait in the assistance line and I was furious- swore I'd never fly with Alaska again- but then the ticket agent was fantastic, calm and helpful and helped put me in a better mood. Overall flight was great. Felt safe, hardly any turbulence and friendly flight staff. Flight was on time. No delays.

No screens on the back of seats with free entertainment. I don't like paying extra for entertainment. I wish you had good vegan food options.

SEA
ANC
Excellent 10.0

Excellent Crew - I flew standby, so have great gate agents and flight attendants makes all the difference when you’re hoping for a seat. In flight they are professional and personable and keep you up to date on what you need to know! Plus, I’m always happy when my flights have USB ports so I’m fully charged when I deplane.

I always want more leg room or a little more room under the seat in front of me. But I didn’t upgrade for a roomier seat and there was more than enough overhead space, so truly can’t complain about it!

Sun, Mar 11
SEA
IAD
4h 48m
Wed, Mar 14
IAD
SEA
5h 55m
Trip: 3 days
Overall 0.0 Poor
Based on 0 reviews
Wed, May 9
SEA
IAD
5h 00m
Wed, May 16
IAD
SEA
5h 39m
Trip: 8 days
Overall 0.0 Poor
Based on 0 reviews
Tue, Dec 19
SEA
IAD
4h 52m
Thu, Dec 28
IAD
SEA
6h 05m
Trip: 10 days
8.7ExcellentShow reviews
Overall 8.7 Excellent
Based on 36 reviews
Overall
8.6
Boarding
8.7
Comfort
8.4
Crew
8.9
Entertainment
7.8
Food
8.0
SEA
IAD
Good 6.0

Wifi didn't work. Very dissappointing.

SEA
IAD
Excellent 10.0

Flight had open seats in fact I had a whole row to myself. Plane was clean and new, it even had plug-ins for every seat for charging devices. WiFi was was overpriced but they had movies you could rent and some free. Flights were on time.

PHX
SEA
Excellent 10.0

Excellent Crew - I flew standby, so have great gate agents and flight attendants makes all the difference when you’re hoping for a seat. In flight they are professional and personable and keep you up to date on what you need to know! Plus, I’m always happy when my flights have USB ports so I’m fully charged when I deplane.

I always want more leg room or a little more room under the seat in front of me. But I didn’t upgrade for a roomier seat and there was more than enough overhead space, so truly can’t complain about it!

SEA
IAD
Excellent 8.3

Friendly and calm professionals in the "assistance" line. The ticket kiosk did not recognize my confirmation number or name so I was instructed to wait in the assistance line and I was furious- swore I'd never fly with Alaska again- but then the ticket agent was fantastic, calm and helpful and helped put me in a better mood. Overall flight was great. Felt safe, hardly any turbulence and friendly flight staff. Flight was on time. No delays.

No screens on the back of seats with free entertainment. I don't like paying extra for entertainment. I wish you had good vegan food options.

SEA
IAD
Excellent 8.6

The crew was extremely pleasant and genuinely accommodating. (and USB ports on every seat?!

No cash-handling for meals and services... (but that's my fault for assuming it would be cash only).

Sat, Dec 23
SEA
IAD
28h 30m
Sat, Dec 30
IAD
SEA
6h 05m
Trip: 8 days
8.7ExcellentShow reviews
Overall 8.7 Excellent
Based on 36 reviews
Overall
8.6
Boarding
8.7
Comfort
8.4
Crew
8.9
Entertainment
7.8
Food
8.0
SEA
ANC
Excellent 10.0

Excellent Crew - I flew standby, so have great gate agents and flight attendants makes all the difference when you’re hoping for a seat. In flight they are professional and personable and keep you up to date on what you need to know! Plus, I’m always happy when my flights have USB ports so I’m fully charged when I deplane.

I always want more leg room or a little more room under the seat in front of me. But I didn’t upgrade for a roomier seat and there was more than enough overhead space, so truly can’t complain about it!

SJC
SEA
Good 6.0

Airplane was dirty upon boarding - food and miscellaneous remnants on the seats and floor, used trash bag in the seat back in front of me

SEA
IAD
Excellent 10.0

I loved the free chat and free entertainment! It made such a long flight go so much better and goodbyes and travel easier knowing that I could communicate on the go! For someone with social anxiety, being able to talk to loved ones when I was going through things was the best experience ever! Thank you so much!

SEA
LAX
Good 6.0

737 900

Delay at gate....computer issues????

SEA
IAD
Excellent 10.0

The staff was really friendly, easy boarding, great fast baggage claim. overall great!

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