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$52+ Cheap flights from Sky Harbor Intl (PHX) 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 10/7. Fares are subject to change and may not be available on all flights or dates of travel.
PHX — DEN
Nov 1 — Nov 81
Sat 11/1
Sat 11/8
1 adult, Economy
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Cheapflights Tip: The best prices from Phoenix Sky Harbor Intl to Boulder are usually found in February or January, booked 62 days in advance, depart on a Thursday or Friday and return on a Wednesday

Cheap flight deals from Sky Harbor Intl to Boulder

Keep the following information in mind while searching for Sky Harbor Intl to Boulder flight deals. Data was last updated October 2, 2025.

Round-trip from

$86
(Priceline)

One-way from

$52
(Booking.com)

Popular in

June

Cheapest in

February

Average price

$137
From Phoenix Sky Harbor Intl to Boulder
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One-way flight from Phoenix Sky Harbor Intl to Boulder
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Highest demand for flights based on searches. 14% potential increase in price ($27 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($4 potential savings vs. average RT price).
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Average for round-trip flights in October 2025
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Find flight deals from Sky Harbor Intl to Boulder

Cheapest flights from Sky Harbor Intl to Boulder
Explore the most affordable flight options available from Sky Harbor Intl to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 2, 2025.

This Priceline deal was found by Cheapflights users on 9/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/279:59 pmPHX - DEN
Nonstop1h 57mFrontier
Wed 11/57:30 amDEN - PHX
Nonstop2h 01mFrontier
Deal found 9/30$86
This Kiwi.com deal was found by Cheapflights users on 10/1. 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.
Thu 10/169:59 pmPHX - DEN
Nonstop1h 57mFrontier
Sat 10/188:55 pmDEN - PHX
Nonstop2h 00mFrontier
Deal found 10/1$87
This Cheapflightsfares deal was found by Cheapflights users on 10/1. 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 11/710:53 pmPHX - DEN
Nonstop1h 54mFrontier
Thu 11/136:20 amDEN - PHX
Nonstop2h 04mFrontier
Deal found 10/1$88
This Cheapflightsfares deal was found by Cheapflights users on 9/30. 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.
Fri 10/316:36 amPHX - DEN
Nonstop1h 59mFrontier
Sun 11/29:21 amDEN - PHX
Nonstop2h 04mFrontier
Deal found 9/30$89
This Priceline deal was found by Cheapflights users on 9/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/167:21 amPHX - DEN
Nonstop1h 57mFrontier
Mon 10/206:55 amDEN - PHX
Nonstop2h 04mFrontier
Deal found 9/30$90
This Cheapflightsfares deal was found by Cheapflights users on 10/1. 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 10/3011:30 amPHX - DEN
Nonstop1h 58mFrontier
Mon 11/247:03 pmDEN - PHX
Nonstop2h 01mFrontier
Deal found 10/1$91
This Cheapflightsfares deal was found by Cheapflights users on 9/30. 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.
Thu 10/239:59 pmPHX - DEN
Nonstop1h 57mFrontier
Sun 10/266:55 amDEN - PHX
Nonstop2h 04mFrontier
Deal found 9/30$92
This Cheapflightsfares deal was found by Cheapflights users on 10/2. 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.
Fri 10/179:59 pmPHX - DEN
Nonstop1h 57mFrontier
Wed 10/228:55 pmDEN - PHX
Nonstop2h 00mFrontier
Deal found 10/2$93
This CheapOair deal was found by Cheapflights users on 10/1. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/612:55 pmPHX - DEN
Nonstop2h 01mFrontier
Sun 11/97:44 pmDEN - PHX
Nonstop2h 00mFrontier
Deal found 10/1$94
This Priceline deal was found by Cheapflights users on 9/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/18:20 amPHX - DEN
Nonstop2h 01mFrontier
Fri 11/710:29 pmDEN - PHX
Nonstop2h 00mFrontier
Deal found 9/30$95
This Cheapflightsfares deal was found by Cheapflights users on 9/30. 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.
Fri 10/249:59 pmPHX - DEN
Nonstop1h 57mFrontier
Sun 10/266:55 amDEN - PHX
Nonstop2h 04mFrontier
Deal found 9/30$97
This Cheapflightsfares deal was found by Cheapflights users on 9/30. 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 10/154:14 pmPHX - DEN
Nonstop1h 56mFrontier
Thu 10/166:55 amDEN - PHX
Nonstop2h 04mFrontier
Deal found 9/30$98

Cheapflights Fare Finder

 
Customize your flight search to find flights from Sky Harbor Intl 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 October 2, 2025.
Use the filters below to find and compare flights from Phoenix Sky Harbor Intl Airport to Boulder that are best for you.

Fly from

Sky Harbor Intl

Fly to

Boulder

Route

Depart

Return

Price

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Fri 10/17

9:59 pm-12:56 am

Nonstop1h 57m

Denver Intl

Mon 10/20

7:19 pm-8:19 pm

Nonstop2h 00m

$101

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Sat 11/15

10:57 am-12:53 pm

Nonstop1h 56m

Denver Intl

Sun 11/16

12:59 am-3:03 pm

1 stop14h 04m

$104

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Tue 10/28

7:32 am-10:29 am

Nonstop1h 57m

Denver Intl

Wed 10/29

2:37 pm-6:50 pm

1 stop5h 13m

$110

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Thu 10/16

9:59 pm-12:56 am

Nonstop1h 57m

Denver Intl

Sun 10/19

8:56 pm-9:14 am

1 stop13h 18m

$121

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Fri 10/17

9:59 pm-12:56 am

Nonstop1h 57m

Denver Intl

Tue 10/21

12:36 am-1:17 pm

1 stop13h 41m

$132

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Sat 10/18

7:05 am-10:02 am

Nonstop1h 57m

Denver Intl

Tue 10/21

4:55 pm-5:59 pm

Nonstop2h 04m

$142

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Sat 12/6

10:22 am-7:24 pm

1 stop9h 02m

Denver Intl

Wed 12/10

10:05 am-3:13 pm

1 stop5h 08m

$156

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Sat 12/13

10:22 am-7:24 pm

1 stop9h 02m

Denver Intl

Wed 12/17

10:05 am-3:13 pm

1 stop5h 08m

$156

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Sat 11/1

9:05 am-12:00 pm

Nonstop1h 55m

Denver Intl

Mon 11/3

3:55 pm-5:50 pm

Nonstop1h 55m

$157

PhoenixDenver

PHX - DEN

PHXDEN

Phoenix Sky Harbor Intl

Wed 12/10

4:33 pm-6:25 pm

Nonstop1h 52m

Denver Intl

Sun 12/14

8:50 pm-10:51 pm

Nonstop2h 01m

$157

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/30

Showing 1-10 of 20 results
1
2

Best time to book a flight from Sky Harbor Intl to Boulder

Have a flexible travel schedule? Discover the best time to fly to Boulder from Sky Harbor Intl 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 Phoenix Sky Harbor Intl Airport to Boulder

How far ahead should I book a flight from Phoenix Sky Harbor Intl Airport to Boulder?

Use this chart to determine the optimal time to book a round-trip flight from Sky Harbor Intl to Boulder. Price data was last updated on September 26, 2025.

To ensure you get the cheapest price possible for a flight from Phoenix Sky Harbor Intl Airport to Boulder, you should look to book at least 62 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

What is the cheapest month to book a flight from Phoenix Sky Harbor Intl Airport to Boulder?

Currently, October is the cheapest month in which you can book a flight from Phoenix Sky Harbor Intl Airport to Boulder (average of $197). Flying from Phoenix Sky Harbor Intl Airport 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 PHX to BD9?

Find hourly flight availability from Sky Harbor Intl 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 October 2, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Phoenix Sky Harbor Intl Airport to Boulder as you normally would.

What is the cheapest day to fly from Phoenix Sky Harbor Intl Airport to Boulder?

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

Travelers seeking maximum savings on their Phoenix Sky Harbor Intl Airport to Boulder flight should consider departing on Friday evenings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Phoenix Sky Harbor Intl Airport to Boulder

Explore weekly flight availability from Sky Harbor Intl 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 October 2, 2025.

The most flights from PHX to BD9 are scheduled on a Thursday (43 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (10 on average).

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 October 2, 2025.
Read through reviews of airlines operating flights from Phoenix Sky Harbor Intl Airport to Boulder, such as Southwest, United Airlines, and American Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,248 reviews

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
Southwest
8.0
Very good
4,248 reviews
Southwest
8.0
Very good
4,248 reviews

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
United Airlines
7.4
Good
8,933 reviews
Southwest
8.0
Very good
4,248 reviews

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
American Airlines
7.2
Good
11,033 reviews
Southwest
8.0
Very good
4,248 reviews

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.
Frontier
5.8
Fair
3,155 reviews
Southwest
8.0
Very good
4,248 reviews

Food

7.0

Overall

8.0

Crew

8.6

Boarding

8.1

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.

Related info for your journey

Find useful and relevant information for your journey from Sky Harbor Intl 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 Phoenix Sky Harbor Intl Airport to Boulder?

    Airlines like Frontier fly from Phoenix Sky Harbor Intl Airport to Boulder in about 1h 57m. The time it takes to get you to your destination is usually consistent. Phoenix Sky Harbor Intl Airport and Boulder are separated by a distance of 601 mi. Generally, flights for this route are nonstop.

  • What are the cheapest airlines to fly from Phoenix Sky Harbor Intl Airport to Boulder one-way?

    The cheapest airlines for a one-way flight from Phoenix Sky Harbor Intl Airport to Boulder are United Airlines ($69), Southwest ($69), and Frontier ($72).

  • What are the most reliable airlines from Phoenix Sky Harbor Intl Airport to Boulder?

    Consider Envoy Air (83%), Air Canada (81%) or Lufthansa (79%) when booking your flight. These represent the most reliable airlines when flying from Phoenix Sky Harbor Intl Airport to Boulder.

  • What are the cheapest flights from Phoenix Sky Harbor Intl Airport to Boulder?

    Looking at all options, your cheapest flight can be booked for $70. While the most popular route (Phoenix Sky Harbor Intl - Denver Intl) can be booked for $66 on average, our data indicates $902 when flying from Phoenix Sky Harbor Intl Airport to Boulder.

  • Can I find deals for flights from Sky Harbor Intl to Boulder that include hotel bookings?

    Yes. In addition to deals on Sky Harbor Intl to Boulder flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Sky Harbor Intl to Boulder?

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

  • Can I find deals for business class flights from Sky Harbor Intl to Boulder?

    Yes. Cheapflights offers flight deals from Sky Harbor Intl 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 Phoenix Sky Harbor Intl Airport to Boulder?

    Currently, October is the cheapest month in which you can book a flight from Phoenix Sky Harbor Intl Airport to Boulder (average of $197). Flying from Phoenix Sky Harbor Intl Airport 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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Top 5 airlines flying from Sky Harbor Intl to Boulder

Discover the top 5 airlines that operate flights from Sky Harbor Intl 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 October 2, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$65Average$142FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$137Average$224FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$150Average$269FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$150Average$307FlexibilityNo cancel feeOn-time69%
DeltaCheapest$206Average$235FlexibilityNo cancel feeOn-timeN/A

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