$661 Find Cheap Flights to Boulder

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 7/9. 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

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Cheap Flights to Boulder

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for return flights 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 return flight deals to Boulder

Do, 25 Sep - Sa, 1 Nov
 Logo
10:20 - 23:45SYD-DEN
29h 25m2 stops
 Logo
12:59 - 09:15DEN-SYD
51h 16m2 stops
$1,429
Find Deal
Do, 7 Aug - So, 10 Aug
Air Canada Logo
09:20 - 19:30SYD-DEN
26h 10m1 stop
Air Canada Logo
15:52 - 07:20DEN-SYD
23h 28m2 stops
$1,458Air Canada
Find Deal
Do, 25 Sep - Sa, 1 Nov
Air Canada Logo
09:20 - 12:28SYD-DEN
19h 08m1 stop
Air Canada Logo
17:30 - 09:35DEN-SYD
47h 05m2 stops
$1,463Air Canada
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Di, 11 Nov - Mo, 17 Nov
Air New Zealand Logo
11:45 - 17:58SYD-DEN
24h 13m2 stops
Air New Zealand Logo
16:05 - 10:30DEN-SYD
24h 25m2 stops
$1,514Air New Zealand
Find Deal
So, 20 Jul - Fr, 8 Aug
Air New Zealand Logo
11:50 - 22:29SYD-DEN
26h 39m2 stops
Air New Zealand Logo
17:59 - 10:35DEN-SYD
24h 36m2 stops
$1,520Air New Zealand
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Di, 7 Okt - Di, 14 Okt
United Airlines Logo
11:55 - 22:27MEL-DEN
27h 32m2 stops
United Airlines Logo
19:10 - 09:15DEN-MEL
21h 05m1 stop
$1,971United Airlines
Find Deal
So, 7 Sep - Do, 2 Okt
United Airlines Logo
10:55 - 19:40MEL-DEN
24h 45m2 stops
United Airlines Logo
08:00 - 08:15DEN-MEL
32h 15m1 stop
$2,121United Airlines
Find Deal
Fr, 8 Aug - Fr, 15 Aug
Qantas Airways Logo
09:45 - 17:29MEL-DEN
23h 44m1 stop
Qantas Airways Logo
17:59 - 06:45DEN-MEL
20h 46m1 stop
$2,305Qantas Airways
Find Deal
Fr, 22 Aug - Di, 26 Aug
Virgin Australia Logo
06:25 - 22:18HBA-DEN
31h 53m2 stops
Virgin Australia Logo
13:30 - 12:10DEN-HBA
30h 40m2 stops
$2,925Virgin Australia
Find Deal
Fr, 22 Aug - Di, 26 Aug
Virgin Australia Logo
06:25 - 22:27HBA-DEN
32h 02m2 stops
Virgin Australia Logo
17:59 - 18:50DEN-HBA
32h 51m2 stops
$2,936Virgin Australia
Find Deal
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Good to know – Book Cheap Boulder Plane Tickets

Low seasonNovember
High seasonDecember
Cheapest flight$661
Best time to beat the crowds but there is an average 11% increase in price.
Most popular time to fly (31% 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). KAYAK recommends you fly to Denver Intl.

  • How far is Denver Intl Airport from central Denver?

    There are 30 km between Denver city centre and Denver Intl Airport.

  • What is the name of Denver’s airport?

    All flights to Denver land at Denver Intl Airport. 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.

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.

Reviews of the 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.
8.0
Air New ZealandOverall score based on 494 reviews
8.2Boarding
8.6Crew
7.5Entertainment
8.0Comfort
7.3Food
Airline reviews

Our original flight was cancelled from SFO to AKL on 6/16/25. So we had to stay overnight at a hotel after a 12-hour layover plus 3-hour delay before the cancellation. Then had to fly to LA and then to AKL the following day losing an entire day of our vacation in NZ, that we can never get back.

2.0 MediocreAnonymous, July 2025SFO - AKL
Read more Air New Zealand reviews

Our original flight was cancelled from SFO to AKL on 6/16/25. So we had to stay overnight at a hotel after a 12-hour layover plus 3-hour delay before the cancellation. Then had to fly to LA and then to AKL the following day losing an entire day of our vacation in NZ, that we can never get back.

Full flight. Flight attendants were harried. Otherwise, fine for the typical cramped seating conditions in coach.

Great! Flight was delayed by 30 mins but all was great. Thanks.

The 10hr flight was a comfortable as it could be in row 57. The food was just very bad….bland and soggy!

The business class upgrade meant a good sleep on the way home after a long week away. Excellent service, great food, and comfortable seat/bed for the journey.

I love the “boarding from the back” idea - it’s so much better than the “Zones” idea that many others use. Also, the inflight wifi was a first for me! Very nice to have on a 13-hour flight!

Again, Air New Zealand was great. They kept bathrooms clean, food was actually very good, New Zealand wines a big hit

The issue was with getting our boarding pases. There were issues with our arrangements that were made through Kayak. I am sorry to say that we will not use you again because of this. The flight itself was good and the flight attendants excellent.

Arriving at Coolangatta, rows 20 forward, took the airbridge across to the terminal. It was suggested to those from rows 21 back, that we take the rear stairs and to be careful crossing the tarmac. That was all well and good. However, when we got across to the terminal we then had to climb three large flights of stairs to meet up with those coming across the airbridge. No elevator! There were people carrying babies and elderly carrying hand luggage that needed assistance from others.. There was no option to turn back.

USB charging ports did not work on any of Air New Zealand flights

One of the oldest most uncomfortable "lay down" seats I've ever experienced. Old plane and old seats that don't lay flat. The seat back does not even recline - at all. Instead the legrest awkwardly extends to fill the gap between a small cubby into which you must insert your feet/legs. I am 5' 11" and could not lay straight but had to tuck my knees. Ticket was also very expensive. Would not recommend flying business/first on Finair from Melbourne to Bangkok and will not do so again myself.

The wifi was out. Otherwise it was great flight. Richard, as CSM, was excellent.

Traditional economy class. Not a full flight so spare seats. Food and drinks were good

Was bumped to a later flight because of inefficiency on part of the airline.

Inflight entertainment, poor that there are no headrest screens on aircraft used for an international flight.

The Emerits/Qantas flight was cancelled to Wellington. We need a refund. Had to buy another airline ticket. How do we get the refund. Still not in Wellington.

Delayed QF59 flight once again, Qantas doesn't fail in maintaining there delayed departures and arrivals. USB points do not work nor do the power point sockets on the plane, Qantas staff admitted that on the flight. Don't expect to your charge devices. Saving grace, was the ice cream. Bottom line, if you expect to fly to HND and make it on time avoid Qantas and if you're interested in ice cream - visit 7/11.

Pretty excellent. I don’t know what the pilot could have done better with the bumping ( there was a storm) nor what happened to my ears coming down into bendigo. It doesn’t happen coming down into Sydney just the return flight. I wonder why?

Touch screens were very difficult to use, generally being laggy and unresponsive- it was quite an art to get it to play the thing you wanted rather than some thing at random. Selection of films and Tv was good when touchscreen decided to finally respond.

Their aircraft are old and amenities lack way behind other international carriers leaving from BNE. Even in economy

4.5 hr international flight. We got a glass of water. Ranks up there with Ryan Air, Easy Jet, Spirit and Frontier. Expected better.

Gluten free options less explicit on business class, but great service

Very good… seems the virgin staff particularly in the lounge and in flight exceeded expectations.

I liked everything about the experience but would have liked some free snacks!

Crew was great but flight was delayed almost three hours due to a technical issue and we had to go back to the terminal and wait for another one.

Being told why we delayed three hours and not even given an apology by someone. Not a word. Not my airline of choice ever.

Checked Baggage line up was long but moved quickly, rest of the process, boarding, crew was excellent

Virgin has always provided a smooth and comfortable flight. This one was no different. Seats are comfortable. Staff are great. This is my favourite airline.

Virgin changed the flight to an Alliance flight. Smaller plane, tea coffee and water the only refreshments available and not sure what happened to the extra money I paid to sit in a selected seat with extra leg room. This is obviously a regular switch as it happened on our flight there and back. Do not recommend.

Late boarding, late departure due to weather and slow boarding, packed 5+hour flight, only 2 toilets for main cabin, tight leg room, no free food except tea, coffee, and water, arrived 75 minutes late.

Very rough getting into denver. my kid threw up it was so rough.

Why wasn't this flight departure scheduled eith another crew so that it could leave on time? When we arrived in Denver we had so little time between flights we had run to the connecting flight. We should received some credit for the inconvenience.

Efficient, calm when things were delayed and kept us regularly informed of what was happening.

I was supposed to be on business class at first class from Denver back to Miami due to weather changes. I missed my connection and it’s put on a flight to Fort Lauderdale. Instead of honoring my business class/1st class ticket, they put me in coach, but there were two first class seats open. I think it’s absolutely disgusting that I paid for first class $1300 ticket and they put me in economy and they had to open seats available and I have still not been refunded the difference. I ended up having to eat a snack box instead of the meal I was supposed to get and did not get home till 2 AM so I think that’s a little pathetic that I had to live off crackers for dinner And my poor dog ate some cheese and salami. Oh yes, apparently when they switched me to the new flight they forgot to mention I had a service dog

Excellent service despite turbulence during the flight. Flight attendants were remarkable!

Flight attendant moved my bag without notifying me and was rude to me when I asked him about it. There was no reason to move it.

The gate attendant let me walk right by her with a bag too big for the overhead compartment

Plane temperature was comfortable (not to hot) when boarding and waiting for takeoff.

Food choices were very limited. Taste of the dishes was average.

I liked all the informational texts. I always knew where to go and when .

Pros: The airplane was new and had in-flight entertainment (tablet behind seats) with new movies instead of watching on personal devices. Cons: the flight time was changed without informing us. When I booked the flight, the time was 13:30pm (also in the email confirmation). However, when I reached the airport, the time was conveniently changed to 14:55pm. When I asked at the counter, they said the flight always took off at this time. The booking was made by Air Canada, but the flight was operated by United.

United had no (zero) record of our flight. It took over an hour of us standing in line with surly employee while others waited to get resolved. I have never experienced such poor service and poor empathy.

Took off on-time and staff was very nice. Got stuck on tarmac at ATL due to storms, but staff was still wonderful even though they were working and not getting paid.

In a nutshell, my bag, the one I have to pay for, because now you can’t even bring a carry on, did not make it. I am still waiting for an update. The fact that not only were have to pay for it, but on top of that we are stuck without getting it, it’s ridiculous..

The plane was filthy!!!! There were empty food wrappers in the pockets and worst of all a wad of hair where someone had obviously brushed their hair, cleaned out the brush and left the wad of hair in the pocket. It was the most disgusting thing I’ve ever seen!! The seats are so crammed together with NO leg room. The AC vent controllers do not adjust. I will likely not book another AC flight from Florida to Montreal.

This was an excellent experience for a very short flight.

Registered my luggage at 5pm. Arrived at JFK at 1:00 am. Worst trip ever. Never again

Really good, super comfy flight and the stewardess was great.

Air Canada never runs on time. You’re lucky if your flight is not cancelled or diverted. Worst airline in the world for gas lighting its customers.

No space in overhead bin, one cookie, 2 oz of juice - is not customer service.

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