$98+ Cheap flights from Seattle (SEA) to Boulder, CO
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 8/25. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — DEN
Jul 2 — Jul 91
Round-trip
1 adult, Economy
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Find cheap flights from Seattle to Boulder 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 Seattle/Tacoma Intl to Boulder are usually found in January or October, booked 61 days in advance, depart on a Friday or Thursday and return on a Friday
Cheap flight deals from Seattle to Boulder
Cheapest
Best
Last-minute
One-way
Cheapest flights from Seattle to BoulderExplore the most affordable flight options available from Seattle to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 2, 2026.
Explore the most affordable flight options available from Seattle to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 2, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 5/30. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/197:41 pm
SEA
- DEN
Nonstop2h 55m
Frontier
Wed 8/2610:25 am
DEN
- SEA
1 stop25h 10m
Frontier
Deal found 5/30![Frontier logo]()
$166
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/197:41 pm
SEA
- DEN
Nonstop2h 55m
Frontier
Tue 8/258:44 am
DEN
- SEA
1 stop11h 14m
Frontier
Deal found 6/1![Frontier logo]()
$168
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/253:19 pm
SEA
- DEN
Nonstop2h 48m
Frontier
Wed 8/267:45 am
DEN
- SEA
Nonstop3h 03m
Frontier
Deal found 6/1![Frontier logo]()
$169
This Cheapflightsfares deal was found by Cheapflights users on 6/1. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/1312:35 pm
SEA
- DEN
Nonstop3h 05m
Frontier
Mon 8/177:13 am
DEN
- SEA
Nonstop3h 04m
Frontier
Deal found 6/1![Frontier logo]()
$170
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/203:19 pm
SEA
- DEN
Nonstop2h 48m
Frontier
Mon 8/2412:00 pm
DEN
- SEA
Nonstop3h 04m
Frontier
Deal found 6/1![Frontier logo]()
$172
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/137:06 pm
SEA
- DEN
Nonstop2h 52m
Frontier
Mon 8/317:45 am
DEN
- SEA
Nonstop3h 03m
Frontier
Deal found 6/1![Frontier logo]()
$176
This Kiwi.com deal was found by Cheapflights users on 6/1. 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 8/197:41 pm
SEA
- DEN
Nonstop2h 55m
Multiple Airlines
Sat 8/293:00 pm
DEN
- SEA
Nonstop2h 56m
Multiple Airlines
Deal found 6/1![Multiple Airlines logo]()
$178
This Cheapflightsfares deal was found by Cheapflights users on 6/1. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/67:06 pm
SEA
- DEN
Nonstop2h 52m
Frontier
Wed 8/127:13 am
DEN
- SEA
Nonstop3h 04m
Frontier
Deal found 6/1![Frontier logo]()
$179
This Cheapflightsfares deal was found by Cheapflights users on 6/2. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/197:41 pm
SEA
- DEN
Nonstop2h 55m
Frontier
Sun 8/237:45 am
DEN
- SEA
Nonstop3h 03m
Frontier
Deal found 6/2![Frontier logo]()
$180
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/27:41 pm
SEA
- DEN
Nonstop2h 55m
Frontier
Mon 9/712:00 pm
DEN
- SEA
Nonstop3h 04m
Frontier
Deal found 6/1![Frontier logo]()
$181
This Frontier deal was found by Cheapflights users on 6/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/197:41 pm
SEA
- DEN
Nonstop2h 55m
Frontier
Thu 8/2712:32 pm
DEN
- SEA
1 stop6h 54m
Frontier
Deal found 6/1![Frontier logo]()
$182
Best flights from Seattle to BoulderDiscover carefully curated flight deals from Seattle to Boulder that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 2, 2026.
Discover carefully curated flight deals from Seattle to Boulder that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 2, 2026.
This Delta deal was found by Cheapflights users on 6/1. 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 8/158:07 pm
SEA
- DEN
Nonstop2h 51m
Delta
Tue 9/16:44 pm
DEN
- SEA
Nonstop3h 02m
Delta
Deal found 6/1![Delta logo]()
$215
This Southwest deal was found by Cheapflights users on 6/1. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/146:15 pm
SEA
- DEN
Nonstop2h 45m
Southwest
Tue 8/186:15 am
DEN
- SEA
1 stop6h 50m
Southwest
Deal found 6/1![Southwest logo]()
$285
This Alaska Airlines deal was found by Cheapflights users on 6/1. 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 7/13:55 pm
SEA
- DEN
1 stop4h 45m
Alaska Airlines
Sat 7/411:32 am
DEN
- SEA
1 stop6h 26m
Alaska Airlines
Deal found 6/1![Alaska Airlines logo]()
$325
This Delta deal was found by Cheapflights users on 6/1. 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.
Mon 8/178:07 pm
SEA
- DEN
Nonstop2h 51m
Delta
Fri 8/281:21 pm
DEN
- SEA
Nonstop3h 02m
Delta
Deal found 6/1![Delta logo]()
$290
This Southwest deal was found by Cheapflights users on 6/1. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/203:25 pm
SEA
- DEN
2 stops7h 20m
Southwest
Mon 8/249:45 am
DEN
- SEA
2 stops8h 20m
Southwest
Deal found 6/1![Southwest logo]()
$295
This Delta deal was found by Cheapflights users on 6/1. 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.
Fri 8/148:07 pm
SEA
- DEN
Nonstop2h 51m
Delta
Sun 8/306:20 am
DEN
- SEA
Nonstop2h 59m
Delta
Deal found 6/1![Delta logo]()
$331
This Southwest deal was found by Cheapflights users on 5/28. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/67:30 am
SEA
- DEN
1 stop7h 05m
Southwest
Sat 7/114:10 pm
DEN
- SEA
2 stops8h 05m
Southwest
Deal found 5/28![Southwest logo]()
$350
This Delta deal was found by Cheapflights users on 5/30. 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.
Wed 7/155:30 am
SEA
- DEN
1 stop5h 17m
Delta
Wed 7/2212:45 pm
DEN
- SEA
1 stop4h 43m
Delta
Deal found 5/30![Delta logo]()
$345
This Southwest deal was found by Cheapflights users on 5/28. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/1211:40 am
SEA
- DEN
1 stop6h 05m
Southwest
Sun 8/166:05 pm
DEN
- SEA
2 stops7h 45m
Southwest
Deal found 5/28![Southwest logo]()
$351
This Delta deal was found by Cheapflights users on 5/30. 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.
Wed 7/155:30 am
SEA
- DEN
1 stop5h 17m
Delta
Tue 7/2112:45 pm
DEN
- SEA
1 stop4h 43m
Delta
Deal found 5/30![Delta logo]()
$345
This Southwest deal was found by Cheapflights users on 5/28. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/247:30 am
SEA
- DEN
2 stops8h 35m
Southwest
Sat 6/274:10 pm
DEN
- SEA
2 stops8h 00m
Southwest
Deal found 5/28![Southwest logo]()
$356
This Delta deal was found by Cheapflights users on 5/27. 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.
Fri 7/107:59 pm
SEA
- DEN
Nonstop2h 45m
Delta
Sun 7/127:09 pm
DEN
- SEA
1 stop5h 50m
Delta
Deal found 5/27![Delta logo]()
$357
Last-minute flights from Seattle to BoulderDiscover last-minute flight deals from Seattle to Boulder. Data last updated June 2, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to Boulder. Data last updated June 2, 2026 and is based on user searches.
This deal was found by Cheapflights users on 6/1. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/67:50 pm
SEA
- DEN
Nonstop3h 04m
Frontier
Sun 6/217:45 am
DEN
- SEA
Nonstop3h 03m
Frontier
Deal found 6/1![Frontier logo]()
$260
This deal was found by Cheapflights users on 6/1. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/67:50 pm
SEA
- DEN
Nonstop3h 04m
Frontier
Mon 6/227:45 am
DEN
- SEA
Nonstop3h 03m
Frontier
Deal found 6/1![Frontier logo]()
$283
This deal was found by Cheapflights users on 5/28. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/113:33 pm
SEA
- DEN
Nonstop2h 48m
Frontier
Mon 6/157:45 am
DEN
- SEA
Nonstop3h 03m
Frontier
Deal found 5/28![Frontier logo]()
$254
This Cheapflightsfares deal was found by Cheapflights users on 5/29. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/118:12 pm
SEA
- DEN
1 stop27h 26m
Frontier
Tue 6/304:26 pm
DEN
- SEA
1 stop19h 09m
Frontier
Deal found 5/29![Frontier logo]()
$267
This eDestinos deal was found by Cheapflights users on 5/28. 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 eDestinos is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/118:12 pm
SEA
- DEN
1 stop12h 03m
Frontier
Sun 6/148:44 am
DEN
- SEA
1 stop11h 13m
Frontier
Deal found 5/28![Frontier logo]()
$280
This Cheapflightsfares deal was found by Cheapflights users on 5/28. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/118:12 pm
SEA
- DEN
1 stop14h 07m
Frontier
Thu 6/1812:47 pm
DEN
- SEA
1 stop22h 48m
Frontier
Deal found 5/28![Frontier logo]()
$286
This Cheapflightsfares deal was found by Cheapflights users on 5/29. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/1111:03 am
SEA
- DEN
1 stop6h 28m
Frontier
Tue 6/1612:47 pm
DEN
- SEA
1 stop22h 48m
Frontier
Deal found 5/29![Frontier logo]()
$287
This Cheapflightsfares deal was found by Cheapflights users on 5/29. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/1111:03 am
SEA
- DEN
1 stop6h 28m
Frontier
Sat 7/412:14 pm
DEN
- SEA
Nonstop3h 04m
Frontier
Deal found 5/29![Frontier logo]()
$290
This Cheapflightsfares deal was found by Cheapflights users on 5/28. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/118:12 pm
SEA
- DEN
1 stop20h 52m
Frontier
Fri 6/197:45 am
DEN
- SEA
Nonstop3h 03m
Frontier
Deal found 5/28![Frontier logo]()
$291
One-way flights from Seattle to BoulderSearch for one-way flight options from Seattle to Boulder. Find affordable one-way fares based on user searches. Data last updated June 2, 2026.
Search for one-way flight options from Seattle to Boulder. Find affordable one-way fares based on user searches. Data last updated June 2, 2026.
This Delta deal was found by Cheapflights users on 6/1. 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.
Wed 8/268:40 am
SEA
- DEN
Nonstop2h 46m
Delta
Deal found 6/1![Delta logo]()
$98
This Kiwi.com deal was found by Cheapflights users on 5/31. 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 8/2611:03 am
SEA
- DEN
1 stop30h 23m
Frontier
Deal found 5/31![Frontier logo]()
$104
This Cheapflightsfares deal was found by Cheapflights users on 5/30. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/77:06 pm
SEA
- DEN
Nonstop2h 52m
Frontier
Deal found 5/30![Frontier logo]()
$106
This United Airlines deal was found by Cheapflights users on 6/1. 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 8/255:20 pm
SEA
- DEN
1 stop6h 39m
United Airlines
Deal found 6/1![United Airlines logo]()
$108
This Mytrip deal was found by Cheapflights users on 5/30. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/157:06 pm
SEA
- DEN
Nonstop2h 52m
Frontier
Deal found 5/30![Frontier logo]()
$109
This Cheapflightsfares deal was found by Cheapflights users on 6/1. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/287:41 pm
SEA
- DEN
Nonstop2h 55m
Frontier
Deal found 6/1![Frontier logo]()
$111
This Super.com deal was found by Cheapflights users on 5/29. 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.
Wed 7/18:12 pm
SEA
- DEN
1 stop6h 46m
Frontier
Deal found 5/29![Frontier logo]()
$114
This Frontier deal was found by Cheapflights users on 5/29. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/228:13 pm
SEA
- DEN
1 stop6h 35m
Frontier
Deal found 5/29![Frontier logo]()
$115
This Delta deal was found by Cheapflights users on 6/1. 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 8/158:07 pm
SEA
- DEN
Nonstop2h 51m
Delta
Deal found 6/1![Delta logo]()
$118
This Cheapflightsfares deal was found by Cheapflights users on 6/1. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/2810:34 am
SEA
- DEN
1 stop22h 29m
Frontier
Deal found 6/1![Frontier logo]()
$119
Find flight deals from Seattle to Boulder
Keep the following information in mind while searching for Seattle to Boulder flight deals. Data was last updated June 2, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $166 (Cheapflightsfares) |
One-way from | $98 (Delta) |
Popular in | June |
Cheapest in | January |
Average price | $281 |
Cheapflights Fare Finder
Customize your flight search to find flights from Seattle to Boulder 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 2,558,603 searches. Data last updated June 2, 2026.
Use the filters below to find and compare flights from Seattle to Boulder that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Sat 8/15
8:07 pm-11:58 pm
Nonstop2h 51m
Denver Intl
Tue 9/1
6:44 pm-8:46 pm
Nonstop3h 02m
$215
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Fri 8/14
6:15 pm-10:00 pm
Nonstop2h 45m
Denver Intl
Tue 8/18
6:15 am-12:05 pm
1 stop6h 50m
$285
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Mon 8/17
8:07 pm-11:58 pm
Nonstop2h 51m
Denver Intl
Fri 8/28
1:21 pm-3:23 pm
Nonstop3h 02m
$290
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Thu 8/20
3:25 pm-11:45 pm
2 stops7h 20m
Denver Intl
Mon 8/24
9:45 am-5:05 pm
2 stops8h 20m
$295
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Wed 7/1
3:55 pm-9:40 pm
1 stop4h 45m
Denver Intl
Sat 7/4
11:32 am-4:58 pm
1 stop6h 26m
$325
Quickest round-trip
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Fri 8/14
8:07 pm-11:58 pm
Nonstop2h 51m
Denver Intl
Sun 8/30
6:20 am-8:19 am
Nonstop2h 59m
$331
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Wed 7/15
5:30 am-11:47 am
1 stop5h 17m
Denver Intl
Wed 7/22
12:45 pm-4:28 pm
1 stop4h 43m
$345
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Wed 7/15
5:30 am-11:47 am
1 stop5h 17m
Denver Intl
Tue 7/21
12:45 pm-4:28 pm
1 stop4h 43m
$345
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Mon 7/6
7:30 am-3:35 pm
1 stop7h 05m
Denver Intl
Sat 7/11
4:10 pm-11:15 pm
2 stops8h 05m
$350
SeattleDenver
SEA - DEN
SEADEN
Seattle/Tacoma Intl
Wed 8/12
11:40 am-6:45 pm
1 stop6h 05m
Denver Intl
Sun 8/16
6:05 pm-12:50 am
2 stops7h 45m
$351
Showing 1-10 of 22 resultsSorted by cheapest first
Best time to book a flight from Seattle to Boulder
Have a flexible travel schedule? Discover the best time to fly to Boulder from Seattle with our price prediction graph.
SEA-DEN
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 Seattle to Boulder
SEA-BD9
SEA-DEN
What is the cheapest time of day to fly from SEA to BD9?
Find hourly flight availability from Seattle to Boulder. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 2, 2026.
Unlike in the morning, when flights are generally more expensive, you can save up to 24% on flights from Seattle to Boulder by exploring options for tickets in the evening.
Weekly flight availability from Seattle to Boulder
Explore weekly flight availability from Seattle to Boulder. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 2, 2026.
The most flights from SEA to BD9 are scheduled on a Monday (41 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (17 on average).
How much does it cost to fly round-trip from Seattle to Boulder?
What is the cheapest day to fly from Seattle to Boulder?
Use this chart to determine the cheapest time to fly round-trip from Seattle to Boulder. Price data was last updated on May 30, 2026.
Travelers seeking maximum savings on their Seattle to Boulder flight should consider departing on Saturday evenings when fares are most often at their lowest. Sunday mornings flights should be avoided if possible as fares are typically the most expensive at this time.
Reviews of airlines servicing Boulder
Get insights into the airlines that provide service to Boulder. 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 Boulder. Reviews last updated June 2, 2026.
See what other customers who have flown with Southwest,Alaska Airlines, andDelta from Seattle to Boulder have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Entertainment
7.5
Food
7.0
Boarding
8.1
Crew
8.6
Comfort
8.0
Overall
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Entertainment
7.5
Food
7.0
Boarding
8.1
Crew
8.6
Comfort
8.0
Overall
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Entertainment
7.5
Food
7.0
Boarding
8.1
Crew
8.6
Comfort
8.0
Overall
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Entertainment
7.5
Food
7.0
Boarding
8.1
Crew
8.6
Comfort
8.0
Overall
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Entertainment
7.5
Food
7.0
Boarding
8.1
Crew
8.6
Comfort
8.0
Overall
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Entertainment
7.5
Food
7.0
Boarding
8.1
Crew
8.6
Comfort
8.0
Overall
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Related info for your journey
Find useful and relevant information for your journey from Seattle to Boulder. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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Seattle and Boulder flights
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Top 7 airlines flying from Seattle to Boulder
Discover the top 7 airlines that operate flights from Seattle to Boulder. 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 2,558,603 searches. Data last updated June 2, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$56 | Average$175 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$69 | Average$213 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$90 | Average$276 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$117 | Average$307 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$117 | Average$298 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$129 | Average$333 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$200 | Average$328 | FlexibilityNo cancel fee | On-time62% |