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$642+ Cheap flights to Boulder

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 23/3. Fares are subject to change and may not be available on all flights or dates of travel.
— DEN
27 Feb — 6 Mar1
1 adult
1 adult, Economy, 0 bags

Flights to Boulder in 2026

Enter your travel dates to find the best prices.

Cheapest flights to Boulder
Explore the most affordable flight options available to Boulder. Find the lowest fares based on data from user searches, with prices last updated on 28 January 2026.

Wed 11/314:00
SYD
-
DEN
2 stops27h 37m
Multiple Airlines
Wed 18/318:11
DEN
-
SYD
2 stops25h 24m
Multiple Airlines
Deal found 25/1$1,216
Wed 22/413:10
SYD
-
DEN
2 stops22h 39m
Multiple Airlines
Wed 20/513:35
DEN
-
SYD
1 stop25h 55m
Multiple Airlines
Deal found 26/1$1,399
Mon 2/214:00
SYD
-
DEN
2 stops38h 30m
Multiple Airlines
Mon 16/206:00
DEN
-
SYD
1 stop31h 25m
Multiple Airlines
Deal found 27/1$1,406
Wed 22/413:10
SYD
-
DEN
2 stops22h 39m
Multiple Airlines
Tue 19/513:35
DEN
-
SYD
1 stop25h 55m
Multiple Airlines
Deal found 26/1$1,408
Sun 8/314:00
SYD
-
DEN
2 stops27h 30m
Multiple Airlines
Sat 14/309:00
DEN
-
SYD
2 stops34h 35m
Multiple Airlines
Deal found 27/1$1,441
Sat 25/409:55
SYD
-
DEN
2 stops25h 45m
Air New Zealand
Wed 20/515:44
DEN
-
SYD
2 stops34h 26m
Air New Zealand
Deal found 26/1$1,478
Thu 23/420:45
SYD
-
DEN
2 stops31h 21m
Multiple Airlines
Wed 20/514:57
DEN
-
SYD
2 stops35h 53m
Multiple Airlines
Deal found 26/1$1,481
Thu 12/314:00
SYD
-
DEN
2 stops27h 30m
Multiple Airlines
Thu 19/309:00
DEN
-
SYD
2 stops44h 05m
Multiple Airlines
Deal found 25/1$1,491
Tue 24/214:00
SYD
-
DEN
2 stops37h 49m
Multiple Airlines
Tue 3/321:31
DEN
-
SYD
1 stop39h 54m
Multiple Airlines
Deal found 26/1$1,510

Find flight deals to Boulder

Find the latest flights to Boulder in 2026, with up-to-date prices and availability. In the last 7 days, Cheapflights users made a total of 647,157 searches and data was last updated on 28 January 2026.

Return from

$1,399

One-way from

$642

Popular in

January

Cheapest in

February

Average price

$1,922
22/4-20/5
  • 22/4-20/5
  • 3 total stops
  • 48h 34m total
  • Sydney to Denver
Search Deals
26/2
  • 26/2
  • 2 total stops
  • 37h 29m total
  • Sydney to Boulder
Search Deals
Highest demand for flights based on searches. 8% potential increase in price ($137 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($40 potential savings vs. average return price).
Search Deals
Average for return flights in January 2026
Search Deals

Cheapflights Fare Finder

 
Locate flights to Boulder that fit your budget, with regularly updated fares and availability. In the last 7 days, Cheapflights users made a total of 647,157 searches and data was last updated on 28 January 2026.
Use the filters below to find and compare flights to Boulder that are best for you.

Fly from

Sydney

Route

Depart

Return

Price

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Wed 11/3

14:00-00:37

2 stops27h 37m

Denver Intl

Wed 18/3

18:11-12:35

2 stops25h 24m

$1,216

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Wed 22/4

13:10-19:49

2 stops22h 39m

Denver Intl

Tue 19/5

13:35-07:30

1 stop25h 55m

$1,408

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Thu 23/4

13:15-19:58

2 stops22h 43m

Denver Intl

Tue 19/5

13:35-07:30

1 stop25h 55m

$1,575

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Sun 26/4

20:45-12:06

2 stops31h 21m

Denver Intl

Wed 20/5

14:57-18:50

2 stops35h 53m

$1,628

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Wed 4/3

11:20-19:14

1 stop25h 54m

Denver Intl

Sun 24/5

11:30-07:05

1 stop27h 35m

$1,634

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Thu 23/4

20:45-12:06

2 stops31h 21m

Denver Intl

Sun 24/5

08:00-18:50

2 stops42h 50m

$1,701

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Mon 23/3

14:00-00:30

2 stops27h 30m

Denver Intl

Mon 30/3

09:00-12:45

2 stops34h 45m

$1,740

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Thu 23/4

20:45-12:06

2 stops31h 21m

Denver Intl

Thu 21/5

12:56-18:50

2 stops37h 54m

$1,760

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Tue 28/4

13:15-19:49

2 stops22h 34m

Denver Intl

Sat 23/5

18:07-07:30

1 stop21h 23m

$1,762

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Mon 23/3

14:00-09:44

2 stops36h 44m

$642

Flights are sorted by cheapest return flights first.

Deals found on 26/1

Showing 1-10 of 17 results
1
2

Best time to book a flight to Boulder

Have a flexible travel schedule? Discover the best time to fly to Boulder with our price prediction graph.
Estimated return 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 to Boulder

When is the best time to book a flight to Boulder?

Use this chart to determine the optimal time to book a return flight from Sydney to Boulder. Price data was last updated on 23 January 2026.

The price you pay for your flight to Boulder may vary depending on when you book. For the best chance of a lower fare, look to book 46 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

How long is the flight to Boulder?

On average, a flight from Sydney to Boulder takes 19 hours 14 minutes. Flights to Boulder from other popular cities in Australia will vary in length. Below are a few examples of popular routes and their flight times.

What are the most popular airlines that fly to Boulder?

The most popular airlines flying from Sydney to Boulder are Qantas Airways, Air Canada and United Airlines.

Qantas Airways
Qantas Airways
From $700
Air Canada
Air Canada
From $1,234
United Airlines
United Airlines
From $1,372
Air New Zealand
Air New Zealand
From $1,239

What are the cheapest airlines that fly to Boulder?

The cheapest airlines flying from Sydney to Boulder are Qantas Airways, Air Canada and Air New Zealand.

Rainfall in Boulder by month

Plan your trip to Boulder by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Boulder ranges from 13.0 - 58.0 mm per month. May is typically the wettest month, when rainfall can reach 58.0 mm. January is typically the driest time to visit Boulder when rainfall is around 13.0 mm.

Temperature in Boulder by month

Plan your trip to Boulder by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Boulder, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 23.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around -1.0 C).

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 28 January 2026.
See what other customers who have flown with Air New Zealand, Qantas Airways, andUnited Airlines to the United States have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Air New Zealand
8.0
Very Good
577 reviews
Check prices

Food

7.4

Boarding

8.2

Overall

8.0

Comfort

8.0

Crew

8.5

Entertainment

7.4

Reviews

1 / 20
8.0
Excellent

David,Jan 2026

AKL - IAH

Couple of spare seats on this flight so people could spread a little. Much better than a full plane
Air New Zealand
8.0
Very Good
577 reviews
Air New Zealand
8.0
Very Good
577 reviews
Check prices

Food

7.4

Boarding

8.2

Overall

8.0

Comfort

8.0

Crew

8.5

Entertainment

7.4

Reviews

1 / 20
8.0
Excellent

David,Jan 2026

AKL - IAH

Couple of spare seats on this flight so people could spread a little. Much better than a full plane
Qantas Airways
7.5
Good
978 reviews
Air New Zealand
8.0
Very Good
577 reviews
Check prices

Food

7.4

Boarding

8.2

Overall

8.0

Comfort

8.0

Crew

8.5

Entertainment

7.4

Reviews

1 / 20
8.0
Excellent

David,Jan 2026

AKL - IAH

Couple of spare seats on this flight so people could spread a little. Much better than a full plane
United Airlines
7.4
Good
9,207 reviews
Air New Zealand
8.0
Very Good
577 reviews
Check prices

Food

7.4

Boarding

8.2

Overall

8.0

Comfort

8.0

Crew

8.5

Entertainment

7.4

Reviews

1 / 20
8.0
Excellent

David,Jan 2026

AKL - IAH

Couple of spare seats on this flight so people could spread a little. Much better than a full plane
Air Canada
7.1
Good
10,660 reviews
Air New Zealand
8.0
Very Good
577 reviews
Check prices

Food

7.4

Boarding

8.2

Overall

8.0

Comfort

8.0

Crew

8.5

Entertainment

7.4

Reviews

1 / 20
8.0
Excellent

David,Jan 2026

AKL - IAH

Couple of spare seats on this flight so people could spread a little. Much better than a full plane

FAQs about flying to Boulder

  • Can I find cheaper flights to Boulder if I am willing to have stopovers?

    Yes, flights with stopovers are often cheaper than direct flights. Keep an eye out for flight deals to Boulder on Cheapflights that require 1 or 2 stops for potential cost savings.

  • What is the best airline to fly to Boulder?

    Based on reviews from Cheapflights users, Qantas Airways is rated the highest out of the airlines that fly to Boulder.

  • How much is a return flight to Boulder?

    A return flight to Boulder will typically cost around $717, however they can be found for as little as $647.

  • Where does the fastest flight to Boulder depart from?

    For those looking to save time traveling to Boulder, Sydney Kingsford Smith offers the quickest one-way flight (19 hours 14 minutes).

  • Does Denver Intl have car hire?

    Yes. Those touching down at Denver Intl can take advantage of the car hire services offered upon their arrival.

  • Are there hotels close to Denver Intl?

    Yes. Denver Intl has hotels nearby for those requiring accommodations. The Westin Denver International Airport is the closest property to Denver Intl (0.0 km away from Denver Intl).

See more FAQs

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