Find flights
When to book
FAQs & Tips
Airlines
Deals

Find cheap flights to Boulder from $1,068

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight to Boulder departing on 20/5. 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
Fri 24/5
Fri 31/5

Search hundreds of travel sites at once for deals on flights to Boulder

In the last 7 days, travellers have searched 44,632,927 times on KAYAK, and here's why:

Save 19% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Free to useThere are no hidden charges or fees.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Good to know

Low season

September

High season

June

Cheapest flight

$1,068
Best time to beat the crowds (7% less expensive on average)
Most popular time to fly (1% more expensive on average)
Flight from Sydney to Denver

FAQs - booking Boulder flights

  • How to fly to Boulder?

    You cannot fly directly to Boulder. KAYAK recommends you fly to Denver Intl (DEN) (53.76 km from Boulder). From there you can hire a car or take a taxi.

  • What airports are near Boulder?

    The closest airport is Denver Intl (DEN) (53.76 km). Another nearby airport is Colorado Springs (COS) (142.97 km) KAYAK recommends you fly to Denver Intl.

  • How far is Denver from central Denver?

    There are 30 km between Denver city centre and Denver.

  • What is the name of Denver’s airport?

    All flights to Denver land at Denver. The airport code is DEN,and it can also be referred to as Denver or Denver Intl.

  • How does KAYAK find such low prices on flights 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 to Boulder.

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

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

  • What is the Hacker Fare option on flights 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 with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight 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 up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

See more FAQs

Top tips for finding cheap flights to Boulder

  • There is no major airport in Boulder. It is instead served by Denver Intl Airport.
  • Enter your preferred departure airport and travel dates into the search form above to unlock the latest Boulder flight deals.

Top 5 airlines flying to Boulder

 
Need help choosing which airline to fly with from Australia 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.
8.2
Air New ZealandOverall score based on 658 reviews
7.9entertainment
8.4boarding
8.1comfort
7.6food
8.8crew
Airline reviews

Overall excellent but the Captain kept the seat belt sign on for far too long, especially at the beginning and end of the flight. It was 2 hours after take-off before the crew were able to start the service (on an 11 hour night flight, reducing our sleeping time) and the seat belt sign on went on during breakfast (90 mins before landing) and was not turned off again until we landed. This made for an uncomfortable journey of trying to limit fluid intake because it was unclear when the toilets would be available for use.

8.0 ExcellentNathan, Mar 2024NRT - AKL
Read more about Air New Zealand reviews

Overall excellent but the Captain kept the seat belt sign on for far too long, especially at the beginning and end of the flight. It was 2 hours after take-off before the crew were able to start the service (on an 11 hour night flight, reducing our sleeping time) and the seat belt sign on went on during breakfast (90 mins before landing) and was not turned off again until we landed. This made for an uncomfortable journey of trying to limit fluid intake because it was unclear when the toilets would be available for use.

The staff and crew on board were excellent. Business class however, was very weird. I thought we would have individual pods, but the way it was set up was unexpected. Not very private and If you wanted to lay down, you had to have an entire bed made up for you by the crew, rather than how Delta one works where you could just lie down whenever you feel like it. It was a 16 hour flight. I chose not to have my bed made, and that turned out to be a good idea because everybody who had their bed made had to wait for the crew to roll up their mattresses. So strange!

Crew were pleasant, happy to be there and were a joy to be around. Entire operation was professional, well thought out and ran like a Swiss clock.

Couldn’t request a vegan meal somehow but I noticed other people getting them

They announced food service but then never came around. We also couldn’t land so kept trying to get to runway and then had to come up and go around happened like 3 times and cause the child next to me to start throwing up

Good food and entertainment options. Great Staff that were all welcoming and caregiving.

The recline on the seat in front of me came back so that I was staring at the top of the man’s head in front of me the whole trip. He refused to bring his seat back up twice every time he was instructed to do so and only relented when he had a tray of good in front of him. And then right back in my lap!!! Horrible man!! I complained to the staff multiple times, but no one would address the issue. Otherwise, it would have been a perfect flight.

Carring crew, nice ambiance of the cabin, comfortable beds, good food well served. We liked everything.

The pilot tried to make up for lost time due to delays that were out of her control. She communicated the issues openly and clearly and made every effort to do what she could to alleviate issues.

So here's the rub - my flight was booked through Chatdeal even though I bought it under the Kayak umbrella. All the return flights were theoretically through Air New Zealand, however except for the initial leg from New Zealand, they were all partnered flights. So when I arrived at the airport in New Zealand they could only issue me my ticket to Fiji. Once in Fiji I had to do some serious leg work and finagling to get my ticket to Los Angeles through Fiji Air. This included a monitored covid RAT that I wasn't aware I needed to do. So I gave the score I did because of the complexity and annoyance created in the process of getting a boarding pass for my Nadi-LA flight.

This time is good . Don’t cancel flight with out early notice .

Very good experience, considering the short flight the meals were served promptly after takeoff.

X class seats in row 3 with the new configuration are very poor in fact I feel 3B and 3E should no longer be considered as X class seat as there is no forward seat pocket available to these seats and greatly reduced leg room due the intrusion of the business class armrests/table module

It was pretty good. Everyone friendly. Like all airlines, the draconian limitations on baggage and weight and not giving even a free soda kind of drags down the experience a bit.

Last 10 minutes boarding they canceled the flight and didn’t organise anything

Estheticly the plane looks great, although the seats are way too upright. If the seats were just slightly more reclined then the comfort level would increase tenfold. I had the stiffest neck after just a short flight due to this. A nap was almost out of the question.

Cabin crew were very professional and welcoming. They certainly appeared to have lifted their game. Congratulations

I know not directly a Virgin "thing" but I hold Virgin responsible for their subcontractors. Had to wait 45 minutes waiting for baggage at PER before the belt conveyor even started. This is unacceptable and hopefully Virgin engages with whoever to pull their fingers out. I realise PER staff are generally slow at the best of times but this was ridiculous. Maybe more seating for those waiting, a cafe in the baggage area for a light meal while we wait or at the very least a troop of dancing girls to entertain the punters while they stare at the conveyor belt start light almost willing it to fire up.

Very poor. Flight was cancelled due to captain exceeding hours. Told to fend for ourselves for 12 hours until a new flight could be done. This meant overnight accommodation in Hobart. Next plane was delayed and no food onboard. No apologies from Virgin. Extremely disappointing.

Flight was cancelled due to a mechanical fault - Virgin rebooked me on a flight 6 hours later so I cancelled and flew with another carrier

Following a marathon flight riddled by delays and changes from Santiago, Chile, my flight to Melbourne from Sydney was on schedule but I was transferred to the next flight. The reason by ticketing and the floor manager was I missed the entry to flight by one minute! That's right, the emphasised that if I was 1 minute earlier I would be on the flight. I asked what was the point them emphasising 1minute overdue and how that helped me or the situation. They didn't care at all. Replying that if it was one minute earlier they would've done something and smirking delivering the information. Australian's do call Australia home, Qantas calls Australian's suckers.

1) crackly headphone jack 2) one of the emergency seats recline. Usually second row does. But in this case neither did 3) food was scrambled eggs or fruit. 4) fruit should not be the option to eggs 5)miserable unpleasant crew not a smile. Thought that was a virgin thing

Qantas are unable to service and unfit for purpose, they cannot transport Australians on time to overseas destinations. On top of the inflated ticketing, the Sydney flight to Santiago was impacted because the plane was delayed arriving and then further bungling by Qantas admitting the ground new ground crew in charge of cleaning were not trained. The impact on passengers with connecting flights was tremendous and long ques of frustrated passengers waiting for rescheduling. **Qantas has become the Australian Spirit of disappointment**

The staff we fantastic and seemed to work very well with each other

Business lounge in Melbourne mediocre. Look at Emirates or Qatar, Qantas! Great friendly crew. Food was good but Emirates is a level above. Business seat good. But can’t compare to Qatar. Main reason for booking Qantas is loyalty and terrific connection via Perth to LHR.

I was pleasantly surprised with my flight to LA with Qantas. Although seats were not the roomies, service was excellent.

The service and smooth landing. Food was delicious and the staff was friendly. We arrived earlier than scheduled.

Wonderful crew, good food. Absolutely loved the wine spritz and wish I could buy it!

Don’t like last minute airline change. Not able to choose seat earlier.

Enjoyed the new possibilities of in flight entertainment. Been awhile since I've flown, and that was a nice surprise. Being able to pick from such a variety was personalized and welcomed.

T hey did a great job. Flight was on time .

Positive: Entertainment via phone on the short was great and my first time. Good food and wine and head phones for free. Negative: Seat hardly reclined on the long flight. Breakfast was an egg with a bun. No egg choices and rather have something sweet like bun/jam and Youghurt.

They did get us booked on a later flight, but it made us miss our connecting flight. So, we had to stay and another state overnight with no luggage or clothes. Because they kept our luggage at airport for next flight on the next day.

Flight was on time. Staff were friendly. I paid for Economy Plus but was required to check my standard carry-on luggage due to lack of space on the aircraft. This cost me 30 minutes, unexpectedly, in waiting at the baggage claim. This experience did not meet my expectations.

Crew is way too many times on the intercom re explaining the same thing

Amazing comfortable chairs great snacks super friendly staff pilots did excellent job. Smooth sailing all the way. Definitely be flying United more.

We waited too long to get water while the plane was on the Tarmac awaiting de-icing.

Easy peasy. Crew was great. Take-off and landing nice anc chill (good job by the pilot). Thank you UA!

Excellent as always. Had issues checking-in online. Please fix.

The plane was delayed coming in and on the tarmac. I was coming from another flight so it made for a very long day. The stewardess kept trying to slam the overhead bins closed and I was worried that she had damaged my new luggage. They ran out of snacks and lccdsddd me a hummus box which was nice. It took them a very long time to pick up the garbage so I could not go to the washroom and had little time. To prepare for disbarment. The TV system was hard to control from the armrest and picture wasn’t clear. The crew did apologize several times for the lateness. It took the Denver airport an unusually long time to de-ice the plane.

It was an excellent experience, traveling from Toronto to Denver with United.

Ontime boarding. Almost 1 hour take off delay. We could have boarded slightly later since the pilots were in traffic

Flight was delayed, I had to put my luggage all the way in the back! They served only a beverage no snack on the way in Air Canada, definitely not a good first impression.

Fresh fuit or veg snacks would be so great, but there are two good restaurants in Denver airport. Try Etais UDIS or Freshens DIA for nutritious delicious pita sandwiches/ donairs and crepes in Freshens.

Crowded plane but it flew on time and had friendly staff

Headphones for the movies have too much bass and can't be adjusted. Almost impossible to hear. Great movie selections but can't really watch them because you can't hear them. Also the system is very slow.

This was the first AC flight in a long time that we experienced no delays or frustrations. The gate attendant was extremely polite and accommodating to my husband who has Parkinson’s disease which made boarding extremely stress free. Flight departed ON TIME and was a smooth ride. If only all my AC experiences could be like this.

The Air Canada agent was very helpful helping with my luggage and cat carrier when I went there instead of United.

United force you to download their App to do the check-in.

I didn’t like the fact that all the customs officers went to lunch so I was in line for 90 minutes due to where the staff directed me. We were told three very different reasons for why the plane was delayed. It was a crowded plane with difficult storage situations for the Carry On bags. The Air Canada airline staff were all very good and professional. I was so disappointed in my cheese and fruit box as the cheese had molded and the fruit wasn’t fresh so I couldn’t eat the majority of the food. This was the last meal I could find as the restaurants had closed when I got in to my destination. I think you could work on improving the food quality.

Book Cheap Boulder Plane Tickets

Recent return flight deals

22/7Mon
1 stopAmerican Airlines
18h 03mSYD-DEN
11/9Wed
2 stopsAmerican Airlines
20h 10mDEN-SYD
$1,424
24/7Wed
1 stopAmerican Airlines
24h 30mSYD-DEN
11/9Wed
1 stopAmerican Airlines
21h 22mDEN-SYD
$1,435
16/5Thu
1 stopQantas Airways
18h 56mSYD-DEN
5/6Wed
1 stopQantas Airways
20h 30mDEN-SYD
$2,291
16/5Thu
1 stopQantas Airways
39h 45mSYD-DEN
5/6Wed
1 stopQantas Airways
20h 30mDEN-SYD
$2,297
30/9Mon
1 stopUnited Airlines
18h 08mSYD-DEN
3/11Sun
1 stopUnited Airlines
22h 54mDEN-SYD
$2,424
24/5Fri
1 stopAir Canada
18h 33mBNE-DEN
5/6Wed
1 stopAir Canada
20h 00mDEN-BNE
$2,429
23/5Thu
3 stopsAir Canada
41h 21mBNE-DEN
30/5Thu
2 stopsAir Canada
29h 15mDEN-BNE
$2,458
1/10Tue
1 stopVirgin Australia
22h 19mSYD-DEN
31/10Thu
1 stopVirgin Australia
27h 21mDEN-SYD
$2,461
4/10Fri
1 stopUnited Airlines
18h 08mSYD-DEN
30/10Wed
1 stopUnited Airlines
19h 25mDEN-SYD
$2,498
30/6Sun
1 stopVirgin Australia
22h 54mMEL-DEN
4/8Sun
1 stopVirgin Australia
30h 10mDEN-MEL
$2,953

Search by stops

Search by airline

Search by price

Recent one-way flight deals

20/5Mon
3 stops
35h 30mSYD-DEN
$1,068
20/5Mon
3 stops
33h 00mSYD-DEN
$1,135
26/8Mon
1 stopQantas Airways
28h 17mSYD-DEN
$1,514
17/10Thu
1 stopQantas Airways
21h 58mSYD-DEN
$1,517
12/10Sat
1 stopUnited Airlines
20h 54mSYD-DEN
$1,616
16/9Mon
1 stopUnited Airlines
27h 08mSYD-DEN
$1,676
20/9Fri
1 stopVirgin Australia
25h 20mSYD-DEN
$1,767
16/9Mon
1 stopVirgin Australia
39h 15mMEL-DEN
$1,818
29/6Sat
1 stopAmerican Airlines
22h 10mMEL-DEN
$1,835
29/6Sat
2 stopsAmerican Airlines
25h 58mMEL-DEN
$1,849

Search by stops

Search by airline

Search by price

Flights to Boulder

Browse origins:

Browse destinations: