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$562+ 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 15/10. Fares are subject to change and may not be available on all flights or dates of travel.
— DEN
12 Oct — 19 Oct1
1 adult
1 adult, Economy

Flights to Boulder in 2025

Find the latest flights to Boulder in 2025, 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 12 September 2025.

Return from

$1,303

One-way from

$562

Popular in

December

Cheapest in

February

Average price

$1,779
United Airlines
  • United Airlines
  • 22/9-24/9
  • 3 total stops
  • 70h 54m total
  • Sydney to Denver
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15/10
  • 15/10
  • 3 total stops
  • 42h 59m total
  • Sydney to Boulder
Search Deals
Highest demand for flights based on searches. 18% potential increase in price ($557 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($109 potential savings vs. average return price).
Search Deals
Average for return flights in September 2025
Search Deals

Find flight deals to Boulder

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 12 September 2025.

Mon 27/1017:45SYD - DEN
1 stop24h 07mMultiple Airlines
Wed 12/1111:45DEN - SYD
1 stop25h 40mMultiple Airlines
Deal found 12/9$1,274
Mon 27/1017:45SYD - DEN
1 stop24h 07mMultiple Airlines
Tue 11/1111:45DEN - SYD
1 stop25h 40mMultiple Airlines
Deal found 12/9$1,277
Mon 22/910:20SYD - DEN
2 stops38h 07mUnited Airlines
Wed 24/906:08DEN - SYD
1 stop32h 47mUnited Airlines
Deal found 9/9$1,303
Thu 30/1017:45SYD - DEN
2 stops21h 04mMultiple Airlines
Wed 12/1111:45DEN - SYD
1 stop25h 40mMultiple Airlines
Deal found 12/9$1,306
Tue 7/1018:45SYD - DEN
1 stop32h 34mMultiple Airlines
Wed 5/1111:45DEN - SYD
1 stop25h 40mMultiple Airlines
Deal found 10/9$1,316
Sun 26/1010:30SYD - DEN
2 stops38h 06mMultiple Airlines
Sun 2/1108:00DEN - SYD
1 stop31h 05mMultiple Airlines
Deal found 11/9$1,336
Fri 31/1017:45SYD - DEN
1 stop24h 12mMultiple Airlines
Wed 12/1111:45DEN - SYD
1 stop25h 40mMultiple Airlines
Deal found 12/9$1,371
Wed 29/1011:20SYD - DEN
1 stop23h 24mAmerican Airlines
Tue 11/1118:14DEN - SYD
1 stop20h 46mAmerican Airlines
Deal found 12/9$1,377
Sat 11/1018:45SYD - DEN
1 stop32h 33mMultiple Airlines
Sat 18/1022:55DEN - SYD
1 stop39h 35mMultiple Airlines
Deal found 10/9$1,380
Tue 28/1010:20SYD - DEN
2 stops24h 43mAir Canada
Mon 10/1115:53DEN - SYD
2 stops28h 47mAir Canada
Deal found 12/9$1,383
Tue 28/1011:20SYD - DEN
1 stop21h 28mAmerican Airlines
Mon 10/1106:00DEN - SYD
1 stop30h 55mAmerican Airlines
Deal found 12/9$1,387

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 12 September 2025.
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

Sun 26/10

10:30-07:36

2 stops38h 06m

Denver Intl

Sun 2/11

08:00-09:05

1 stop31h 05m

$1,336

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Mon 2/2

11:20-17:44

1 stop24h 24m

Denver Intl

Fri 20/2

19:05-09:35

1 stop20h 30m

$1,350

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Tue 7/10

10:10-17:44

1 stop24h 34m

Denver Intl

Wed 5/11

14:49-09:00

2 stops24h 11m

$1,393

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Tue 28/10

09:40-14:46

2 stops22h 06m

Denver Intl

Wed 12/11

06:05-08:30

2 stops32h 25m

$1,410

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Thu 30/10

09:40-18:56

2 stops26h 16m

Denver Intl

Tue 11/11

12:18-08:30

2 stops26h 12m

$1,410

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Thu 30/10

09:40-19:01

2 stops26h 21m

Denver Intl

Sun 9/11

12:18-08:30

2 stops26h 12m

$1,410

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Tue 28/10

09:40-19:01

2 stops26h 21m

Denver Intl

Tue 11/11

12:18-08:30

2 stops26h 12m

$1,410

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Wed 29/10

09:40-11:48

1 stop19h 08m

Denver Intl

Sat 8/11

19:41-08:30

2 stops42h 49m

$1,410

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Wed 29/10

09:40-18:56

2 stops26h 16m

Denver Intl

Sun 9/11

12:18-08:30

2 stops26h 12m

$1,410

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Wed 15/10

17:20-10:18

2 stops33h 58m

$630

Flights are sorted by cheapest return flights first.

Deals found on 10/9

Showing 1-10 of 19 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 29 August 2025.

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 $649
Air Canada
Air Canada
From $858
United Airlines
United Airlines
From $961
Air New Zealand
Air New Zealand
From $861

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 12 September 2025.
See what other customers who have flown with Air New Zealand, Virgin Australia, andQantas Airways 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
505 reviews
Check prices

Comfort

8.0

Entertainment

7.4

Overall

8.0

Food

7.3

Crew

8.5

Boarding

8.2

Reviews

1 / 20
6.0
Good

Anonymous,July 2025

AKL - SFO

Flight was delayed an hour. We had just flown Air NZ on a 12- hour flight from AKL so the extra delay on this connecting flight wasn’t welcomed.
Air New Zealand
8.0
Very Good
505 reviews
Air New Zealand
8.0
Very Good
505 reviews
Check prices

Comfort

8.0

Entertainment

7.4

Overall

8.0

Food

7.3

Crew

8.5

Boarding

8.2

Reviews

1 / 20
6.0
Good

Anonymous,July 2025

AKL - SFO

Flight was delayed an hour. We had just flown Air NZ on a 12- hour flight from AKL so the extra delay on this connecting flight wasn’t welcomed.
Virgin Australia
7.6
Good
416 reviews
Air New Zealand
8.0
Very Good
505 reviews
Check prices

Comfort

8.0

Entertainment

7.4

Overall

8.0

Food

7.3

Crew

8.5

Boarding

8.2

Reviews

1 / 20
6.0
Good

Anonymous,July 2025

AKL - SFO

Flight was delayed an hour. We had just flown Air NZ on a 12- hour flight from AKL so the extra delay on this connecting flight wasn’t welcomed.
Qantas Airways
7.5
Good
905 reviews
Air New Zealand
8.0
Very Good
505 reviews
Check prices

Comfort

8.0

Entertainment

7.4

Overall

8.0

Food

7.3

Crew

8.5

Boarding

8.2

Reviews

1 / 20
6.0
Good

Anonymous,July 2025

AKL - SFO

Flight was delayed an hour. We had just flown Air NZ on a 12- hour flight from AKL so the extra delay on this connecting flight wasn’t welcomed.
United Airlines
7.4
Good
8,937 reviews
Air New Zealand
8.0
Very Good
505 reviews
Check prices

Comfort

8.0

Entertainment

7.4

Overall

8.0

Food

7.3

Crew

8.5

Boarding

8.2

Reviews

1 / 20
6.0
Good

Anonymous,July 2025

AKL - SFO

Flight was delayed an hour. We had just flown Air NZ on a 12- hour flight from AKL so the extra delay on this connecting flight wasn’t welcomed.
Air Canada
7.1
Good
10,000 reviews
Air New Zealand
8.0
Very Good
505 reviews
Check prices

Comfort

8.0

Entertainment

7.4

Overall

8.0

Food

7.3

Crew

8.5

Boarding

8.2

Reviews

1 / 20
6.0
Good

Anonymous,July 2025

AKL - SFO

Flight was delayed an hour. We had just flown Air NZ on a 12- hour flight from AKL so the extra delay on this connecting flight wasn’t welcomed.

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 $197, however they can be found for as little as $39.

  • Where does the fastest flight to Boulder depart from?

    For those looking to save time traveling to Boulder, Brisbane offers the quickest one-way flight (18 hours 50 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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