$180+ Cheap flights from Dulles Intl (IAD) to Seattle (SEA)
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/12. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
Oct 15 — Oct 221
Round-trip
1 adult, Economy
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Find cheap flights from Dulles Intl to Seattle with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl are usually found in January or February, booked 21 days in advance, depart on a Wednesday or Tuesday and return on a Thursday
Cheap flight deals from Dulles Intl to Seattle
Cheapest
Best
Last-minute
One-way
Cheapest flights from Dulles Intl to SeattleExplore the most affordable flight options available from Dulles Intl to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 15, 2026.
Explore the most affordable flight options available from Dulles Intl to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 15, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/106:00 am -
1 stop29h 58m
Fri 10/169:16 pm -
1 stop30h 04m
Deal found 9/10![Frontier logo]()
$275
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Mon 10/199:16 pm -
2 stops16h 57m
Deal found 9/11![Frontier logo]()
$283
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Thu 10/229:16 pm -
1 stop30h 04m
Deal found 9/11![Frontier logo]()
$284
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Wed 10/214:27 pm -
2 stops16h 07m
Deal found 9/11![Frontier logo]()
$294
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/76:00 am -
1 stop29h 58m
Tue 10/138:00 pm -
2 stops31h 20m
Deal found 9/11![Frontier logo]()
$295
This Super.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Mon 10/129:16 pm -
1 stop30h 04m
Deal found 9/10![Frontier logo]()
$297
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/146:00 am -
1 stop29h 58m
Mon 10/194:27 pm -
2 stops16h 07m
Deal found 9/11![Frontier logo]()
$301
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/66:00 am -
1 stop30h 42m
Mon 10/129:16 pm -
2 stops24h 05m
Deal found 9/11![Frontier logo]()
$303
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Wed 10/710:53 am -
2 stops16h 27m
Deal found 9/11![Frontier logo]()
$305
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/66:00 am -
1 stop30h 42m
Tue 10/208:00 pm -
2 stops18h 13m
Deal found 9/10![Frontier logo]()
$307
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Fri 10/239:16 pm -
1 stop30h 04m
Deal found 9/11![Frontier logo]()
$309
Best flights from Dulles Intl to SeattleDiscover carefully curated flight deals from Dulles Intl to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 15, 2026.
Discover carefully curated flight deals from Dulles Intl to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 15, 2026.
This Alaska Airlines deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/289:38 am -
Nonstop5h 42m
Sat 10/318:15 am -
Nonstop5h 15m
Deal found 9/11![Alaska Airlines logo]()
$377
This United Airlines deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/105:45 pm -
Nonstop5h 52m
Tue 10/137:00 am -
1 stop7h 44m
Deal found 9/10![United Airlines logo]()
$387
This Delta deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/17:05 am -
Nonstop5h 51m
Thu 11/125:35 am -
2 stops16h 06m
Deal found 9/14![Delta logo]()
$431
This United Airlines deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/1110:10 am -
1 stop9h 08m
Mon 12/148:09 am -
Nonstop4h 59m
Deal found 9/11![United Airlines logo]()
$387
This Alaska Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/267:24 pm -
1 stop17h 04m
Fri 10/309:08 pm -
1 stop17h 42m
Deal found 9/14![Alaska Airlines logo]()
$417
This United Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/15:50 pm -
Nonstop6h 06m
Sat 11/78:09 am -
Nonstop4h 59m
Deal found 9/14![United Airlines logo]()
$397
This Delta deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/105:08 pm -
1 stop7h 57m
Fri 10/162:50 pm -
Nonstop4h 59m
Deal found 9/10![Delta logo]()
$447
This Alaska Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/56:46 pm -
1 stop17h 41m
Sun 11/88:48 pm -
1 stop17h 52m
Deal found 9/14![Alaska Airlines logo]()
$417
This United Airlines deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/135:45 pm -
Nonstop5h 52m
Tue 10/207:00 am -
1 stop7h 44m
Deal found 9/13![United Airlines logo]()
$407
This Alaska Airlines deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/267:24 pm -
1 stop17h 04m
Thu 10/298:15 am -
Nonstop5h 15m
Deal found 9/13![Alaska Airlines logo]()
$427
This United Airlines deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/105:40 pm -
1 stop9h 04m
Sun 12/132:05 pm -
1 stop7h 19m
Deal found 9/11![United Airlines logo]()
$422
Last-minute flights from Dulles Intl to SeattleDiscover last-minute flight deals from Dulles Intl to Seattle. Data last updated September 15, 2026 and is based on user searches.
Discover last-minute flight deals from Dulles Intl to Seattle. Data last updated September 15, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Mon 10/199:16 pm -
2 stops16h 57m
Deal found 9/11![Frontier logo]()
$283
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Thu 10/229:16 pm -
1 stop30h 04m
Deal found 9/11![Frontier logo]()
$284
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Wed 10/214:27 pm -
2 stops16h 07m
Deal found 9/11![Frontier logo]()
$294
This Super.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Mon 10/129:16 pm -
1 stop30h 04m
Deal found 9/10![Frontier logo]()
$297
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Wed 10/710:53 am -
2 stops16h 27m
Deal found 9/11![Frontier logo]()
$305
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/56:00 am -
1 stop30h 42m
Fri 10/239:16 pm -
1 stop30h 04m
Deal found 9/11![Frontier logo]()
$309
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/66:00 am -
1 stop30h 42m
Mon 10/129:16 pm -
2 stops24h 05m
Deal found 9/11![Frontier logo]()
$303
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/66:00 am -
1 stop30h 42m
Tue 10/208:00 pm -
2 stops18h 13m
Deal found 9/10![Frontier logo]()
$307
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/76:00 am -
1 stop29h 58m
Tue 10/138:00 pm -
2 stops31h 20m
Deal found 9/11![Frontier logo]()
$295
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/106:00 am -
1 stop29h 58m
Fri 10/169:16 pm -
1 stop30h 04m
Deal found 9/10![Frontier logo]()
$275
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/146:00 am -
1 stop29h 58m
Mon 10/194:27 pm -
2 stops16h 07m
Deal found 9/11![Frontier logo]()
$301
One-way flights from Dulles Intl to SeattleSearch for one-way flight options from Dulles Intl to Seattle. Find affordable one-way fares based on user searches. Data last updated September 15, 2026.
Search for one-way flight options from Dulles Intl to Seattle. Find affordable one-way fares based on user searches. Data last updated September 15, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/1211:16 am -
2 stops30h 56m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$180
This Kiwi.com deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/312:31 pm -
2 stops33h 23m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$181
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/129:06 pm -
2 stops24h 39m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$182
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/57:40 am -
2 stops29h 05m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$184
This Kiwi.com deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/136:00 am -
2 stops39h 45m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$185
This Super.com deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/246:00 am -
1 stop29h 58m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$187
This Kiwi.com deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/49:04 pm -
2 stops39h 38m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$188
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/76:00 am -
2 stops17h 40m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$189
This Kiwi.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/209:06 pm -
2 stops21h 06m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/15![Frontier logo]()
$191
This Kiwi.com deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/77:52 am -
2 stops38h 02m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$192
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/67:40 am -
2 stops34h 32m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$193
Find flight deals from Dulles Intl to Seattle
Discover tips and strategies to find the most affordable flight options for your journey from Dulles Intl (IAD) to Seattle (SEA). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated September 15, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $275 (Kiwi.com) |
One-way from | $180 (Kiwi.com) |
Popular in | June |
Cheapest in | January |
Average price | $397 |
Good round-trip deal | $388 or less |
Good one-way deal | $249 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Dulles Intl to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 7,457,451 searches. Data last updated September 15, 2026.
Use the filters below to find and compare flights from Washington, D.C. Dulles Intl Airport to Seattle that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Mon 10/19
7:24 pm-9:28 am
1 stop17h 04m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$204
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Mon 12/14
7:00 am-10:10 am
Nonstop6h 10m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$219
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Wed 11/4
7:05 am-9:56 am
Nonstop5h 51m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$219
Quickest round-trip
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Wed 10/14
7:02 am-9:44 am
Nonstop5h 42m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$219
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Fri 11/6
7:05 am-9:56 am
Nonstop5h 51m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$219
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Sat 12/12
7:00 am-9:49 am
Nonstop5h 49m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$219
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Fri 11/27
5:50 pm-8:56 pm
Nonstop6h 06m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$237
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Thu 10/8
9:38 am-12:20 pm
Nonstop5h 42m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$259
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Fri 10/16
4:48 pm-11:52 pm
1 stop10h 04m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$259
Washington, D.C.Seattle
IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl
IADSEA
Washington, D.C. Dulles Intl
Mon 11/9
5:16 pm-9:58 pm
1 stop7h 42m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-3:00 am
Nonstop0h 00m
$259
Showing 1-10 of 22 resultsSorted by cheapest first
Compare providers for flights from Dulles Intl to Seattle
Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Dulles Intl to Seattle in September.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy1 star | Trust Score*3 stars |
- Most accurate provider: When it comes to deals on Washington, D.C. Dulles Intl Airport-Seattle flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Washington, D.C. Dulles Intl Airport-Seattle flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Washington, D.C. Dulles Intl Airport-Seattle flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on Washington, D.C. Dulles Intl Airport-Seattle flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Washington, D.C. Dulles Intl Airport-Seattle flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.
Best time to book a flight from Dulles Intl to Seattle
Have a flexible travel schedule? Discover the best time to fly to Seattle from Dulles Intl with our price prediction graph.
IAD-SEA
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from Washington, D.C. Dulles Intl Airport to Seattle
Prices
Airlines
How far ahead should I book a flight from Washington, D.C. Dulles Intl Airport to Seattle?
The price you pay for your flight from Washington, D.C. Dulles Intl Airport to Seattle may vary depending on when you book. For the best chance of a lower fare, look to book 20 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
What is the cheapest month to book a flight from Washington, D.C. Dulles Intl Airport to Seattle?
Currently, January is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Seattle (average of $222). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of $539). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from IAD to SEA?
Find hourly flight availability from Dulles Intl to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 15, 2026.
One of the essential ways to save on airfare from Washington, D.C. Dulles Intl Airport to Seattle is to remain as flexible as possible. Flights that are in the evening tend to be the most expensive. A flight in the morning could potentially save you up to 22% on airfare.
What is the cheapest day to fly from Washington, D.C. Dulles Intl Airport to Seattle?
Use this chart to determine the cheapest time to fly round-trip from Dulles Intl to Seattle. Price data was last updated on September 12, 2026.
Travelers seeking maximum savings on their Washington, D.C. Dulles Intl Airport to Seattle flight should consider departing on Friday evenings when fares are most often at their lowest. Monday evenings flights should be avoided if possible as fares are typically the most expensive at this time.
The best insider tips for Washington, D.C. Dulles Intl Airport to Seattle flights
AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Washington, D.C. Dulles Intl Airport to Seattle trip
Our travel experts
Reviews of airlines servicing Seattle
Get insights into the airlines that provide service to Seattle. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Seattle. Reviews last updated September 15, 2026.
See what other customers who have flown with Alaska Airlines,Delta, andUnited Airlines from Washington, D.C. Dulles Intl Airport to Seattle have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Comfort
7.8
Entertainment
7.0
Boarding
8.1
Overall
7.9
Crew
8.5
Food
7.0
Reviews
1 / 20
8.0
ExcellentAnonymous,Jun 2026
RDU - SEA
Comfort
7.8
Entertainment
7.0
Boarding
8.1
Overall
7.9
Crew
8.5
Food
7.0
Reviews
1 / 20
8.0
ExcellentAnonymous,Jun 2026
RDU - SEA
Comfort
7.8
Entertainment
7.0
Boarding
8.1
Overall
7.9
Crew
8.5
Food
7.0
Reviews
1 / 20
8.0
ExcellentAnonymous,Jun 2026
RDU - SEA
Comfort
7.8
Entertainment
7.0
Boarding
8.1
Overall
7.9
Crew
8.5
Food
7.0
Reviews
1 / 20
8.0
ExcellentAnonymous,Jun 2026
RDU - SEA
Comfort
7.8
Entertainment
7.0
Boarding
8.1
Overall
7.9
Crew
8.5
Food
7.0
Reviews
1 / 20
8.0
ExcellentAnonymous,Jun 2026
RDU - SEA
Comfort
7.8
Entertainment
7.0
Boarding
8.1
Overall
7.9
Crew
8.5
Food
7.0
Reviews
1 / 20
8.0
ExcellentAnonymous,Jun 2026
RDU - SEA
Related info for your journey
Find useful and relevant information for your journey from Dulles Intl to Seattle. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near Seattle?
Book flights to Seattle if you plan to visit one of these locationsSeaTac
Renton
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Olympia
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Snoqualmie
Puyallup
Lynnwood
Centralia
Kent
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Dulles Intl and Seattle flights
Browse other Dulles Intl and Seattle flight options. Last updated on September 15, 2026.
Other flights from Dulles Intl
Browse through other flights departing from Dulles Intl. Flights are based on user searches made on Cheapflights and were last updated on September 15, 2026.
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Top 6 airlines flying from Dulles Intl to Seattle
Discover the top 6 airlines that operate flights from Dulles Intl to Seattle. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 7,457,451 searches. Data last updated September 15, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$138 | Average$467 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$144 | Average$367 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$145 | Average$355 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$199 | Average$452 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$231 | Average$447 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$337 | Average$583 | FlexibilityNo cancel fee | On-time71% |