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$90+ 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 8/25. Fares are subject to change and may not be available on all flights or dates of travel.
WAS — DEN
Aug 5 — Aug 121
Tue 8/5
Tue 8/12
1 adult, Economy
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Cheapflights Tip: The best prices from Washington, D.C. to Boulder are usually found in September or August, booked 64 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 July 31, 2025.

Round-trip from

$164
(Cheapflightsfares)

One-way from

$89
(Frontier)

Popular in

December

Cheapest in

September

Average price

$263
From Washington, D.C. (WAS) to Boulder
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One-way flight from Washington, D.C. (WAS) to Boulder
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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 July 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 July 31, 2025.

This FlightHub deal was found by Cheapflights users on 7/30. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/56:27 pmBWI - DEN
Nonstop4h 02mFrontier
Sun 9/712:16 pmDEN - BWI
Nonstop3h 26mFrontier
Deal found 7/30$165
This Cheapflightsfares deal was found by Cheapflights users on 7/29. 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.
Wed 8/136:00 pmDCA - DEN
Nonstop4h 05mFrontier
Mon 8/186:38 amDEN - DCA
Nonstop3h 26mFrontier
Deal found 7/29$166
This Southwest deal was found by Cheapflights users on 7/31. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/305:05 pmIAD - DEN
Nonstop3h 50mSouthwest
Sat 9/65:25 pmDEN - IAD
Nonstop3h 20mSouthwest
Deal found 7/31$177
This American Airlines deal was found by Cheapflights users on 7/31. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/256:11 amIAD - DEN
1 stop7h 35mAmerican Airlines
Sat 10/252:48 pmDEN - IAD
1 stop6h 03mAmerican Airlines
Deal found 7/31$191
This American Airlines deal was found by Cheapflights users on 7/30. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/275:00 amDCA - DEN
1 stop6h 41mAmerican Airlines
Sat 9/2712:25 pmDEN - DCA
1 stop7h 35mAmerican Airlines
Deal found 7/30$191
This United Airlines deal was found by Cheapflights users on 7/31. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/195:47 pmIAD - DEN
Nonstop3h 51mUnited Airlines
Mon 10/611:59 pmDEN - IAD
Nonstop3h 23mUnited Airlines
Deal found 7/31$199
This Southwest deal was found by Cheapflights users on 7/31. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/99:00 pmBWI - DEN
Nonstop4h 00mSouthwest
Sun 10/125:20 amDEN - BWI
Nonstop3h 20mSouthwest
Deal found 7/31$217
This Frontier deal was found by Cheapflights users on 7/30. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/912:27 pmIAD - DEN
1 stop13h 23mFrontier
Tue 8/121:39 pmDEN - IAD
1 stop8h 40mFrontier
Deal found 7/30$218
This Gotogate deal was found by Cheapflights users on 7/29. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/76:27 pmBWI - DEN
Nonstop4h 02mMultiple Airlines
Thu 9/115:43 pmDEN - BWI
1 stop13h 50mMultiple Airlines
Deal found 7/29$225
This American Airlines deal was found by Cheapflights users on 7/29. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/276:20 pmBWI - DEN
1 stop5h 56mAmerican Airlines
Sat 9/2711:59 pmDEN - BWI
1 stop7h 49mAmerican Airlines
Deal found 7/29$231
This Delta deal was found by Cheapflights users on 7/31. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/247:05 amIAD - DEN
1 stop6h 55mDelta
Thu 9/2512:45 amDEN - IAD
1 stop6h 14mDelta
Deal found 7/31$237

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 July 31, 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

Fri 9/5

6:27 pm-8:29 pm

Nonstop4h 02m

Denver Intl

Sun 9/7

12:16 pm-5:42 pm

Nonstop3h 26m

$165

Washington, D.C.Denver

DCA - DEN

DCADEN

Washington, D.C. Reagan-National

Wed 8/13

6:00 pm-8:05 pm

Nonstop4h 05m

Denver Intl

Mon 8/18

6:38 am-12:04 pm

Nonstop3h 26m

$166

Washington, D.C.Denver

IAD - DEN

IADDEN

Washington, D.C. Dulles Intl

Sat 8/30

5:05 pm-6:55 pm

Nonstop3h 50m

Denver Intl

Sat 9/6

5:25 pm-10:45 pm

Nonstop3h 20m

$177

Washington, D.C.Denver

IAD - DEN

IADDEN

Washington, D.C. Dulles Intl

Sat 10/25

6:11 am-11:46 am

1 stop7h 35m

Denver Intl

Sat 10/25

2:48 pm-10:51 pm

1 stop6h 03m

$191

Washington, D.C.Denver

DCA - DEN

DCADEN

Washington, D.C. Reagan-National

Sat 9/27

5:00 am-9:41 am

1 stop6h 41m

Denver Intl

Sat 9/27

12:25 pm-10:00 pm

1 stop7h 35m

$191

Washington, D.C.Denver

IAD - DEN

IADDEN

Washington, D.C. Dulles Intl

Fri 9/19

5:47 pm-7:38 pm

Nonstop3h 51m

Denver Intl

Mon 10/6

11:59 pm-5:22 am

Nonstop3h 23m

$199

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

Thu 10/9

9:00 pm-11:00 pm

Nonstop4h 00m

Denver Intl

Sun 10/12

5:20 am-10:40 am

Nonstop3h 20m

$217

Washington, D.C.Denver

DCA - DEN

DCADEN

Washington, D.C. Reagan-National

Fri 9/5

4:50 pm-8:45 pm

1 stop5h 55m

Denver Intl

Mon 9/8

7:45 am-4:15 pm

1 stop6h 30m

$219

Washington, D.C.Denver

IAD - DEN

IADDEN

Washington, D.C. Dulles Intl

Tue 8/19

6:14 am-2:58 pm

1 stop10h 44m

Denver Intl

Fri 8/22

12:19 am-8:48 pm

1 stop18h 29m

$220

BaltimoreDenver

BWI - DEN

BWIDEN

Baltimore/Washington

Sun 9/7

6:27 pm-8:29 pm

Nonstop4h 02m

Denver Intl

Thu 9/11

5:43 pm-9:33 am

1 stop13h 50m

$225

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/29

Showing 1-10 of 34 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 July 25, 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 37 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 July 31, 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 July 31, 2025.

The most flights from WAS to BD9 are scheduled on a Thursday (36 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (10 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 July 31, 2025.
Read through reviews of airlines operating flights from Washington, D.C. to Boulder, such as Alaska Airlines, Southwest, and Delta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Southwest
8.0
Very good
4,246 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Delta
8.0
Very good
7,981 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Hawaiian Airlines
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
United Airlines
7.4
Good
8,900 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.

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 popular is this Washington, D.C. to Boulder flight route?

    This flight path from Washington, D.C. to Boulder was viewed by 118 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

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

    For one-way options, check prices for Frontier. According to our data, you can fly for as low as $89. Users have also found prices from $99 and $100 on American Airlines and United Airlines, respectively.

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

    Most travelers choose Baltimore/Washington - Denver Intl, Washington, D.C. Reagan-National - Denver Intl or Washington, D.C. Dulles Intl - 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: United Airlines (86%), Southwest (56%), Frontier (31%).

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

    Looking at all options, your cheapest flight can be booked for $96. While the most popular route (Baltimore/Washington - Denver Intl) can be booked for $135 on average our data indicates $827 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 7 airlines flying from Washington, D.C. to Boulder

Discover the top 7 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 July 31, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$89Average$235FlexibilityNo cancel feeOn-time62%
JetBlueCheapest$128Average$321FlexibilityNo cancel feeOn-time62%
Sun Country AirCheapest$155Average$275FlexibilityNo cancel feeOn-time83%
American AirlinesCheapest$166Average$370FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$190Average$371FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$193Average$451FlexibilityNo cancel feeOn-time69%
DeltaCheapest$216Average$319FlexibilityNo cancel feeOn-timeN/A

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