$56 Find Cheap Flights from Phoenix to Boulder - Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Phoenix to Boulder departing on 6/30. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Everything you should know

Cheapest round-trip
$115
Typical prices: $128-$253
Frontier
Thu 8/20Mon 8/24
PHX - DEN • Non-stop
Cheapest one-way
$56
Typical prices: $109-$265
Frontier
Tue 6/30
PHX - DEN • Non-stop
Arrival airport
You can't fly directly to Boulder. It is served by Denver (DEN), located 33.4 miles from Boulder.
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Flight Deals
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Flight Deals

Cheap Flights from Phoenix to Boulder (PHX-DEN)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Phoenix to Boulder that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Phoenix to Boulder

Thu, Aug 20 - Mon, Aug 24
Frontier Logo
4:09 pm - 7:02 pm
PHX
-
DEN
1h 53mnonstop
Frontier Logo
10:36 pm - 11:34 pm
DEN
-
PHX
1h 58mnonstop
$115Frontier
Fri, Aug 14 - Mon, Aug 17
Frontier Logo
4:48 pm - 7:46 pm
PHX
-
DEN
1h 58mnonstop
Frontier Logo
10:36 pm - 11:27 pm
DEN
-
PHX
1h 51mnonstop
$116Frontier
Mon, Aug 24 - Sat, Aug 29
Frontier Logo
5:15 am - 8:11 am
PHX
-
DEN
1h 56mnonstop
Frontier Logo
10:36 pm - 11:34 pm
DEN
-
PHX
1h 58mnonstop
$117Frontier
Tue, Jul 21 - Fri, Jul 24
Frontier Logo
2:15 pm - 5:10 pm
PHX
-
DEN
1h 55mnonstop
Frontier Logo
6:45 am - 7:40 am
DEN
-
PHX
1h 55mnonstop
$118Frontier
Thu, Aug 13 - Tue, Aug 18
Frontier Logo
4:48 pm - 7:46 pm
PHX
-
DEN
1h 58mnonstop
Frontier Logo
2:45 pm - 3:43 pm
DEN
-
PHX
1h 58mnonstop
$120Frontier
Tue, Jul 28 - Fri, Jul 31
Frontier Logo
2:15 pm - 5:10 pm
PHX
-
DEN
1h 55mnonstop
Frontier Logo
9:15 am - 10:11 am
DEN
-
PHX
1h 56mnonstop
$121Frontier
Tue, Aug 25 - Sat, Sep 5
Frontier Logo
4:29 pm - 7:22 pm
PHX
-
DEN
1h 53mnonstop
Frontier Logo
2:13 pm - 3:14 pm
DEN
-
PHX
2h 01mnonstop
$122Frontier
Wed, Jul 22 - Fri, Jul 31
Frontier Logo
1:35 pm - 4:34 pm
PHX
-
DEN
1h 59mnonstop
Frontier Logo
8:31 pm - 9:28 pm
DEN
-
PHX
1h 57mnonstop
$123Frontier
Sat, Jul 18 - Tue, Jul 21
Frontier Logo
4:48 pm - 7:46 pm
PHX
-
DEN
1h 58mnonstop
Frontier Logo
2:45 pm - 3:43 pm
DEN
-
PHX
1h 58mnonstop
$125Frontier
Sun, Aug 30 - Sun, Aug 30
Frontier Logo
5:15 am - 8:11 am
PHX
-
DEN
1h 56mnonstop
Frontier Logo
10:36 pm - 11:34 pm
DEN
-
PHX
1h 58mnonstop
$126Frontier
Useful Info

Good to know

Low seasonFebruary
Cheapest flight$56
Best time to beat the crowds with an average 18% drop in price.
Most popular time to fly with an average 6% increase in price.
Flight from Phoenix Sky Harbor Airport to Denver

When to book flights from Phoenix to Boulder

Are your dates flexible? Find out the best times to travel from Phoenix to Boulder based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price

FAQs for booking flights from Phoenix Sky Harbor Intl Airport to Boulder

  • Which airports will I be using when flying from Phoenix Sky Harbor Intl Airport to Boulder?

    When flying out of Phoenix Sky Harbor Intl Airport you’ll be using Phoenix Sky Harbor Intl. Boulder does not have its own airport so you’ll be flying into nearby Denver Intl airport, which is 33.4 mi away.

  • How long does a flight from Phoenix Sky Harbor Intl Airport to Boulder take?

    Direct flights cover the 601 miles separating Phoenix Sky Harbor Intl Airport and Boulder in about 1h 45m.

  • How many flights are there between Phoenix Sky Harbor Intl Airport and Boulder?

    39 direct flights run between Phoenix Sky Harbor Intl Airport and Boulder on a daily basis. On average, there are about 275 departures each week.

  • What’s the cheapest day of the week to fly between Phoenix Sky Harbor Intl Airport and Boulder?

    Consider leaving on a Friday and avoid Saturdays if you are looking for the best rates. For your return to Phoenix Sky Harbor Intl Airport, you’ll find the best rates on Fridays and the most expensive ones on Thursdays.

  • How does KAYAK find such low prices on flights from Phoenix to Boulder?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Phoenix to Boulder.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Phoenix to Boulder?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Boulder from Phoenix is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Phoenix to Boulder?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Boulder with an airline and back to Phoenix with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Phoenix to Boulder?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Boulder from Phoenix up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • Which airlines provide the cheapest flights from Phoenix Sky Harbor Intl Airport to Boulder?

    In the last 5 days, the cheapest one-way ticket between Phoenix Sky Harbor Intl Airport and Boulder found on KAYAK was with Frontier for $34. Frontier offered a round-trip connection from $63 and American Airlines from $136.

Top tips for finding cheap flights from Phoenix Sky Harbor Intl Airport to Boulder

  • There is no airport in Boulder. Instead, you’ll be flying into Denver Airport when flying between Phoenix Sky Harbor Intl Airport and Boulder.
  • The cheapest flight from Phoenix Sky Harbor Intl Airport to Boulder was found 69 days before departure, on average.
  • Book at least 2 weeks before departure in order to get a below-average price.
  • High season is considered to be May, June and July. The cheapest month to fly is February.

Reviews of the top 4 airlines serving Phoenix to Boulder

 
Need help choosing which airline to fly with from Phoenix to Boulder? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.9
SouthwestOverall score based on 4241 reviews
8.6Crew
8.0Comfort
7.5Entertainment
7.0Food
8.1Boarding
Airline reviews

Over a 3 hour flight. The turbulence was almost imperceptible except for 2 short periods which were not bad and over quickly. The attendants claimed "Safety first" and sat looking at their phones for 3 hours with no drink or snack service. This isn't the first time with Southwest. I thinkit may be there new plan of operation. Oh, and it was June 18, Southwest's Birthday which offered free drinks. NOT.

4.0 OkayJeff, Jun 2026
MCI - FLL
Read more Southwest reviews

Over a 3 hour flight. The turbulence was almost imperceptible except for 2 short periods which were not bad and over quickly. The attendants claimed "Safety first" and sat looking at their phones for 3 hours with no drink or snack service. This isn't the first time with Southwest. I thinkit may be there new plan of operation. Oh, and it was June 18, Southwest's Birthday which offered free drinks. NOT.

Airline is not very senior friendly. Flights are late, forcing us to run to the connecting flight. Food is awful. Wish they would go back to pretzels and peanuts. During flight, pressurization isn’t quite right and all of our ears get plugged. Everything is nickel and dime, charging for boarding, seat selection and legroom. While a screen at the desk in the gate area says check your roll on bag now for free due to space limitation, the employee at the desk will not check the bag without a $100 fee. Insane.

We waited in the airplane for over 45 min for a southwest employee to make the flight. This cause over half the plane to miss their connecting flight in Denver. When we confronted the desk upon arrival, they told us the only flight they had was the next day leaving at 8:50 pm!!! Or they offered to get us to Burbank or LA, but after that we were on our own to get back to Santa Barbara. I paid for a flight from sba to bna bna to sba. My re entry into mom mode has been 💯 rough because of southwest mistake with my flight. And now I’m leaving to Reno tomorrow for a vballl tournament and just discovered that my leg in Vegas has me and my 3 kids on a stand by flight even though I had booked these ticket last year November!! Do better southwest!

For the first time in a long time, the Wi-Fi actually worked the entire flight! The flight crew was amazing as usual.

Great flight. I didn't get a drink because I was asleep whole on the flight.

It was good from LAX to Phoenix, But the connection in Phoenix to Tulsa was not that great. The staff on both flights were great. The choice of free entertainment was ok nothing to brag about. The 45 min delay because of some electrical issue wasn't great from Phoenix to Tulsa. We sat there with hardly any air, The seat I had was between windows so the side of the plane pushed in on you. My being a bigger man it then made the seating area uncomfortable. The seats on the plane had no power to connect to recharge your phone or anything. I would recommend that they should look into a slot or clamp to hold your phone to enjoy while watching the entertainment choices hands-free. Also make it possible to raise the inner seat by the window be able to raise the arm rest up to make more room for larger people to set more comfortably. I would also say other then that stop price gouging the airfare or nickel and diming everything. Not fair for people having to fly for emergencies and be paying for higher prices due to the season or holidays. Your making your money either way and the cost of flying is still going to be the same regardless if there's 100 people or 200 people.

Mediocre. Boarding is now unpleasant. The employees, once friendly and nice, are now regularly speaking sternly to passengers, badgering them to do things right so they can take off on time and gate check bags because they don't have enough overhead bin space. The pretzel snack was crushed flat and broken into even smaller pieces, which happens frequently lately. Drink service was suspended before they reached my row.

I appreciate the staff who allowed me to board though I arrived a little late! Regarding the assigned seating, I had booked my flight before this change and wasn't aware of the change at the time, and so I didn't select a seat at booking as I didn't realize it was relevant. Better communication about the change would have been helpful for preparing.

WIFI was great. My selection for seating is an aisle, but during my trip, I never had an aisle seat. If we can get that corrected, I will be thrilled.

All good except once again bags took an hour at Midway Airport Happens all the time. Ridiculous

Checking bag at terminal was horrible. No agents to check us in and only 1 kiosk working. Boarding went ok. Crew onboard was very scattered rained. Missed our row while serving and then didn’t see them hardly again.

The entertainment is a bit limited, it would be better if they added some games to play besides the movies and tv shows. But the seats are comfortable and the crew is polite

Food was great. Staff was phenomenal. Seats were a bit hard and could use a lot more entertainment options as far as movies to choose from. WiFi was good. Overall great trip.

Read the fine print. This was my flight home. I booked my flight for the quickest way home. Had a carry-on and a personal item. Same as my outbound flight. Apparently I needed to pre-pay extra for my carry-on. When I checked in, I was told that I had to check it. I said I’ll pay for it, and was told that this wasn’t an option anymore. They said I still had to pay $50 to check my carry-on. I told them I’ll pay whatever to just carry it in as intended. I was not allowed, so eventually I paid $50 to check my carry-on under a plane that was half full, with overhead compartments that were even less full. My white carry-on suitcase was practically destroyed getting from Idaho falls to Denver to Orange County. The low price air fair was a bait and switch. Got me to the gate, made me pay extra, then didn’t even allow me to pay for a carry on. Not to mention that I paid the $8 for WiFi that didn’t work. All to get my suitcase destroyed. I don’t think I’m going to even keep my Untied mileage plus membership and card. Apparently, membership does not have its privileges for this one.

I flew from Santa Fe to Denver to catch a flight to London and the transfer of my luggage on arrival at Denver to the London flight worked perfectly. The crew on the ground and on board for the London flight were so friendly and efficient.

It was a short flight so I was expecting too much

First class ticket gets you no seat back entertainment? I have to bring my own laptop to see a movie? And most of their movies have ADS? No thank you. Worse: Tiny snacks only on a 2 hr flight?

Late- that’s what United does best. Missed my connection, rebooked to a flight 17 hours later and had to spend $500 on a hotel. What did I get? A $15 meal voucher. What can you get in an airport for $15. I hate United so much.

It was good overall except from Omaha to Denver when flight a was a repeatedly delayed apparently due to some issue at Denver. Communications could have been handled better. I had to board then deboard with luggage and board again

Booked through Kayak Business, had a seat in middle and towards back due to booking rate, not comfortable.

The flight attendants were very friendly, efficient, and helpful. The plane was ahead of schedule, and it all went very smoothly. Thank you.

not sure why you ask about food, I n3ver get food on flights except maybe cookies or pretzels. wifi was slow and in and out most of the flight not good.

I'm not sure American is capable of on-time arrivals and departures. When you land at ORD, you almost always get held on the tarmac because your gate is still occupied. I may have missed my connection, but that ended up up being significantly delayed as well. Once again, I finally got home well after midnight.

there are no options s for snack besides cookies would ve nice to have a salty option n

Early morning flight and no food in First Class except a "salmon" box. No thank you. Was informed before take off by Captain that the plane was not serviced before we boarded in Phoenix. How does that happen? Need more frequent additions/turn over on the Entertainment. Thanks

It was the most un-special flight experience in my life.

We called Kayak for a change due to the TSA situation in Atlanta. What we got was a canceled return flight (in error) and we had to find the mistake. Not happy with Kayak who blamed it on AA.

I would have liked vegetarian and gluten free options for evening dinner time flight. I would have like a pillow on the international overnight flight . The veg wrap and oaten desert on the international flight was good

The baggage claim experience was poor. The plane crew and the AA app said that checked baggage in CLT would be at carousel 7 but the sign at Baggage Claim said carousel 1. The carousel 1 sign had the correct flight # listed above the belt. But the luggage never came. I went to an AA baggage claim office after about 1 hour and the clerk directed me to another AA room that was poorly marked, with a closed door and no obvious way to know what to do. Finally someone opened the door and my bag was inside. The clerk was totally unable to explain why.

Lack of gluten free options in food service. I have Celiac disease and it appears you no longer offer special meals for people with dietary restrictions. I am a frequent flyer traveling into and out of Omaha airport. I have noticed over the course of several months that although our flight typically arrives ahead of schedule (awesome job AA!) - we typically sit on the runway for several minutes waiting for the ground crew to get in place. Not sure if it is a ground crew issue or a gate availability issue (due to construction at this airport). Seems to be more of a ground crew being on time issue.

There weren't enough employees at check in took awhile to get bags checked. There wasn't a wheel chair for me, I was sent to someone who turns out to work for a different airline, if My flight hadn't been delayed I probably would have missed my flight as it was, by the time I arrived at my gate, they started boarding in about 15 minutes. I don't know who took me to my gate, definitely was not the normal people who take passengers to the gate. I'm guessing she may have been in a management position. I wish I knew her name, she went beyond to help me. With that said everyone was kind, and were doing the best they could. So, I choose to say it was an Adventure, stressful start, but good. In the end went well. The situation was not only difficult for passengers but the employee's.

The staff at the check in counter was so rude. Made you feel Incompetent

Frontier scheduled a 40 minute connection in DEN. What they failed to mention was that they “close the doors” 20 mins prior to departure, which means you only have 20 mins. Not enough time. Possibly against DOT regulations. Filing complaint.

The bag check, flight check-in, and onboard experience convinced my wife and me that we will actively go out of our way to avoid flying Frontier Airlines in the future. At bag check, we were informed that check-in could only be completed via the Frontier mobile app. Unfortunately, the app was extremely frustrating—sending us through repetitive, confusing loops that repeatedly forced us to decline add-on services with nearly every click. While most airline apps upsell, this one felt intentionally exhausting. As the process dragged on, we became genuinely concerned that my phone battery would die before check-in could be completed. We approached the bag check staff—who were standing together talking—and explained both our frustration and our predicament. They laughed. Later, my wife described the interaction as “gaslighting,” which felt accurate. We were then informed it would cost $25 per person simply to have our boarding passes printed. From that point forward, the tone of the experience was consistently hostile. The bag check employees were condescending and combative, behaving more like bullies than customer service staff. Unfortunately, that same attitude continued onboard. One flight attendant argued with me when I attempted to stow my backpack in the overhead bin. I explained that we had each paid $75 to check our bags specifically so we would not need to use carry-on space and could have adequate legroom. She demanded to see my ticket, pointed out that it said “no carry-on”—which I acknowledged—and I reiterated that this was precisely why we paid to check our bags. Her response was, “I don’t make the rules.” She then walked away, but not before asking if I “truly wanted to fly back to Chicago today?”—an unnecessary and unmistakable threat. It is also worth noting that despite booking our tickets together in the same transaction, we were not seated together. Upon our return to Chicago—where we could once again sit together—we compared onboard experiences. We both remarked on how unhappy the flight attendants appeared and how each of us was separately asked whether we would like to purchase a beverage. We declined. At no point was water mentioned as an option, leaving us with the clear impression that even water came at a cost—or that complimentary water, if available at all, was deliberately left unmentioned. Overall, the experience was shocking and deeply disappointing, but it was also a profound learning experience—one we will not forget and will not repeat. -Steve

It was an early flight and most people napped/slept and the crew let us which was nice.

More inflight connection. And leg space is horrible. And the paying for baggage I'd ridiculous!!!

Our flight was canceled. I will never use Kayak nor Frontier for travel again. The entire experience was a headache.

Good for a budget airline! It was easy to get on, staff was really nice. Can’t say anything about the food or entertainment because it wasn’t available, which is fine.

It was costly and difficult to check in. $85 to take a small suitcase with me, carry on or checked and $75 on the return trip, Plus $25 if I didn't check my self in check in $25, because I couldn't do it on the kiosk. Small very uncomfortable seats, waited on the runway for near an hour each way. It was my worst flight to date.

Due to weather, my flight was delayed, further delayed, then canceled. I eventually got through to a support person who helped me find a different route out of MSP, but to get to DIA, they didn't want to, but eventually did help with the connection ticket purchase. But even this replacement flight was delayed time and time again, and I would have missed my connecting flights and I didn't want to get stuck in a layover city, so after 12 hours at the airport with two young boys who were very tired, we just cancelled our plans and spent the week at home, instead of Nana's.

Everything you need to know for your flight from Phoenix to Boulder

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