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$55+ Cheap flights from Washington, D.C. (WAS) 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 10/24. Fares are subject to change and may not be available on all flights or dates of travel.
WAS — DEN
out 16 — out 231
qui 10/16
qui 10/23
1 adult, Economy
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Cheapflights Tip: The best prices from Washington, D.C. to Boulder are usually found in August or January, booked 30 days in advance, depart on a Wednesday or Saturday and return on a Friday

Cheap flight deals from Washington, D.C. to Boulder

Keep the following information in mind while searching for Washington, D.C. to Boulder flight deals. Data was last updated setembro 16, 2025.

Round-trip from

$145
(Cheapflightsfares)

One-way from

$55
(Cheapflightsfares)

Popular in

December

Cheapest in

August

Average price

$254
From Washington, D.C. (WAS) to Boulder
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One-way flight from Washington, D.C. (WAS) to Boulder
Search Deals
Highest demand for flights based on searches. 2% potential increase in price ($7 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Washington, D.C. to Boulder

Cheapest flights from Washington, D.C. to Boulder
Explore the most affordable flight options available from Washington, D.C. to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on setembro 16, 2025.

This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sex 10/31:00 pmDCA - DEN
Nonstop4h 00mFrontier
ter 10/74:34 pmDEN - DCA
Nonstop3h 25mFrontier
Deal found 9/14$145
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
qua 10/11:00 pmDCA - DEN
Nonstop4h 00mFrontier
sáb 10/411:25 amDEN - DCA
Nonstop3h 34mFrontier
Deal found 9/14$146
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
seg 12/81:00 pmDCA - DEN
Nonstop4h 06mFrontier
seg 12/1511:38 amDEN - DCA
Nonstop3h 21mFrontier
Deal found 9/14$147
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb 10/41:00 pmDCA - DEN
Nonstop4h 00mFrontier
seg 10/66:45 amDEN - DCA
Nonstop3h 25mFrontier
Deal found 9/15$148
This CheapOair 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
qui 11/133:58 pmBWI - DEN
1 stop17h 43mFrontier
sex 11/1412:59 amDEN - BWI
1 stop12h 36mFrontier
Deal found 9/15$149
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
qua 10/87:00 amDCA - DEN
Nonstop4h 08mFrontier
sáb 10/116:38 amDEN - DCA
Nonstop3h 26mFrontier
Deal found 9/15$149
This CheapOair 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
seg 10/275:00 pmIAD - DEN
1 stop6h 26mFrontier
qui 10/301:42 pmDEN - IAD
1 stop7h 47mFrontier
Deal found 9/14$150
This CheapOair 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb 10/1810:00 amBWI - DEN
1 stop11h 59mFrontier
dom 10/199:12 pmDEN - BWI
1 stop19h 56mFrontier
Deal found 9/15$150
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
qui 10/26:31 pmDCA - DEN
Nonstop3h 58mFrontier
dom 10/56:45 amDEN - DCA
Nonstop3h 25mFrontier
Deal found 9/14$150
This Gotogate 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb 10/1810:00 amBWI - DEN
1 stop11h 59mFrontier
sex 10/2412:59 amDEN - BWI
1 stop6h 06mFrontier
Deal found 9/15$151
This CheapOair 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
dom 9/287:45 pmBWI - DEN
1 stop25h 22mFrontier
sex 10/36:00 amDEN - BWI
1 stop13h 14mFrontier
Deal found 9/15$152
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb 9/277:00 amDCA - DEN
Nonstop3h 58mFrontier
dom 10/56:45 amDEN - DCA
Nonstop3h 25mFrontier
Deal found 9/14$152

Cheapflights Fare Finder

 
Customize your flight search to find flights from Washington, D.C. 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 setembro 16, 2025.
Use the filters below to find and compare flights from Washington, D.C. to Boulder that are best for you.

Fly from

Washington, D.C.

Fly to

Boulder

Route

Depart

Return

Price

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

ter 12/23

11:40 am-3:50 pm

1 stop6h 10m

Denver Intl

ter 12/30

5:05 am-10:30 am

Nonstop3h 25m

$157

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

qua 12/31

4:35 pm-7:50 pm

1 stop5h 15m

Denver Intl

qua 1/7

8:20 pm-5:45 am

1 stop7h 25m

$167

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

qua 11/12

9:45 am-2:25 pm

1 stop6h 40m

Denver Intl

dom 11/16

5:30 am-10:55 am

Nonstop3h 25m

$173

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

sex 1/9

2:55 pm-7:30 pm

1 stop6h 35m

Denver Intl

sáb 1/17

5:30 am-3:00 pm

1 stop7h 30m

$183

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

seg 1/5

7:45 am-12:10 pm

1 stop6h 25m

Denver Intl

sex 1/9

10:35 am-7:30 pm

2 stops6h 55m

$204

Washington, D.C.Denver

IAD - DEN

IADDEN

Washington, D.C. Dulles Intl

qua 10/8

10:09 pm-11:57 pm

Nonstop3h 48m

Denver Intl

dom 10/19

11:59 pm-5:22 am

Nonstop3h 23m

$217

Washington, D.C.Denver

IAD - DEN

IADDEN

Washington, D.C. Dulles Intl

seg 1/19

2:24 pm-4:37 pm

Nonstop4h 13m

Denver Intl

qua 1/21

9:50 am-3:13 pm

Nonstop3h 23m

$217

Washington, D.C.Denver

IAD - DEN

IADDEN

Washington, D.C. Dulles Intl

sex 10/24

7:45 pm-9:35 pm

Nonstop3h 50m

Denver Intl

seg 10/27

7:45 am-1:00 pm

Nonstop3h 15m

$217

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

sáb 10/25

4:21 pm-6:17 pm

Nonstop3h 56m

Denver Intl

qua 10/29

2:00 pm-7:21 pm

Nonstop3h 21m

$227

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

sex 11/14

10:10 am-12:17 pm

Nonstop4h 07m

Denver Intl

dom 11/16

5:43 pm-11:04 pm

Nonstop3h 21m

$227

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/14

Showing 1-10 of 60 results
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Best time to book a flight from Washington, D.C. to Boulder

Have a flexible travel schedule? Discover the best time to fly to Boulder from Washington, D.C. with our price prediction graph.
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. to Boulder

How far ahead should I book a flight from Washington, D.C. to Boulder?

Use this chart to determine the optimal time to book a round-trip flight from Washington, D.C. to Boulder. Price data was last updated on September 12, 2025.

The price you pay for your flight from Washington, D.C. to Boulder may vary depending on when you book. For the best chance of a lower fare, look to book 30 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. to Boulder?

Currently, October is the cheapest month in which you can book a flight from Washington, D.C. to Boulder (average of $197). Flying from Washington, D.C. to Boulder in March is currently the most expensive (average of $278). 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 WAS to BD9?

Find hourly flight availability from Washington, D.C. 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 setembro 16, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Washington, D.C. to Boulder as you normally would.

What is the cheapest day to fly from Washington, D.C. to Boulder?

Use this chart to determine the cheapest time to fly round-trip from Washington, D.C. to Boulder. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Washington, D.C. to Boulder flight should consider departing on Saturday at noon when fares are most often at their lowest. Sunday evenings flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Washington, D.C. to Boulder

Explore weekly flight availability from Washington, D.C. 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 setembro 16, 2025.

The most flights from WAS to BD9 are scheduled on a Friday (31 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (22 on average).

How much does it cost to fly round-trip from Washington, D.C. to Boulder?

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 setembro 16, 2025.
Read through reviews of airlines operating flights from Washington, D.C. to Boulder, such as Southwest, Delta, and United Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Entertainment

7.5

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Southwest
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Entertainment

7.5

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Delta
8.0
Very good
7,954 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Entertainment

7.5

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
United Airlines
7.4
Good
8,929 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Entertainment

7.5

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Entertainment

7.5

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Frontier
5.8
Fair
3,172 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Entertainment

7.5

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Related info for your journey

Find useful and relevant information for your journey from Washington, D.C. to Boulder. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Washington, D.C. to Boulder?

    A quick flight from Washington, D.C. to Boulder can take about 3h 48m. Southwest provides one of the quickest options available for as low as $217. Airlines will cover a distance of 1448 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines to fly from Washington, D.C. to Boulder one-way?

    For one-way options, check prices for Southwest. According to our data, you can fly for as low as $74. Users have also found prices from $74 and $88 on United Airlines and Frontier, respectively.

  • What are the most popular routes from Washington, D.C. to Boulder?

    Most travelers choose Baltimore/Washington - Denver Intl, Washington, D.C. Dulles Intl - Denver Intl or Washington, D.C. Reagan-National - Denver Intl when deciding on the best route from Washington, D.C. to Boulder.

  • What are the most reliable airlines from Washington, D.C. to Boulder?

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Washington, D.C. to Boulder on time: Ethiopian Air (89%), United Airlines (76%), Copa Airlines (74%).

  • What are the cheapest flights from Washington, D.C. to Boulder?

    Looking at all options, your cheapest flight can be booked for $98. While the most popular route (Baltimore/Washington - Denver Intl) can be booked for $133 on average, our data indicates $779 when flying from Washington, D.C. to Boulder.

  • Can I find deals for flights from Washington, D.C. to Boulder that include hotel bookings?

    Yes. In addition to deals on Washington, D.C. to Boulder flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Washington, D.C. to Boulder?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Washington, D.C. to Boulder.

  • Can I find deals for business class flights from Washington, D.C. to Boulder?

    Yes. Cheapflights offers flight deals from Washington, D.C. to Boulder by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Washington, D.C. to Boulder?

    Currently, October is the cheapest month in which you can book a flight from Washington, D.C. to Boulder (average of $197). Flying from Washington, D.C. to Boulder in March is currently the most expensive (average of $278). 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.

See more FAQs

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Alternative routes for Washington, D.C. to Boulder

See prices for flight routes from nearby airports that may be better suited for you.
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Top 6 airlines flying from Washington, D.C. to Boulder

Discover the top 6 airlines that operate flights from Washington, D.C. 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 setembro 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$103Average$236FlexibilityNo cancel feeOn-time62%
JetBlueCheapest$128Average$321FlexibilityNo cancel feeOn-time62%
DeltaCheapest$158Average$312FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$160Average$363FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$178Average$371FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$202Average$430FlexibilityNo cancel feeOn-time69%

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