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$889+ 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 27/1. Fares are subject to change and may not be available on all flights or dates of travel.
— DEN
11 Jan — 18 Jan1
1 adult
1 adult, Economy, 0 bags

Flights to Boulder in 2025

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 12 December 2025.

Wed 17/1212:10SYD - DEN
1 stop18h 00mUnited Airlines
Sun 4/119:37DEN - SYD
1 stop19h 28mUnited Airlines
Deal found 10/12$1,675
Wed 17/1212:10SYD - DEN
1 stop20h 37mUnited Airlines
Sat 3/115:57DEN - SYD
2 stops23h 08mUnited Airlines
Deal found 10/12$1,750
Fri 19/1211:20SYD - DEN
1 stop23h 17mUnited Airlines
Sat 3/119:48DEN - SYD
1 stop41h 12mUnited Airlines
Deal found 10/12$1,786
Sat 20/1211:20SYD - DEN
1 stop24h 59mUnited Airlines
Sat 3/119:48DEN - SYD
1 stop41h 12mUnited Airlines
Deal found 11/12$1,787
Sun 14/1212:10SYD - DEN
1 stop20h 37mUnited Airlines
Sun 28/1217:42DEN - SYD
1 stop21h 23mUnited Airlines
Deal found 10/12$2,448
Sun 14/1221:40SYD - DEN
2 stops31h 05mMultiple Airlines
Tue 16/1206:45DEN - SYD
2 stops43h 00mMultiple Airlines
Deal found 10/12$2,902
Wed 17/1210:40SYD - DEN
2 stops26h 18mDelta
Sun 4/107:10DEN - SYD
2 stops31h 20mDelta
Deal found 10/12$3,049

Find flight deals to Boulder

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 December 2025.

Return from

$1,428

One-way from

$889

Popular in

December

Cheapest in

February

Average price

$2,188
Air New Zealand
  • Air New Zealand
  • 3/5-18/5
  • 4 total stops
  • 51h 45m total
  • Sydney to Denver
Search Deals
27/1
  • 27/1
  • 3 total stops
  • 37h 56m total
  • Sydney to Boulder
Search Deals
Highest demand for flights based on searches. 16% potential increase in price ($318 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($57 potential savings vs. average return price).
Search Deals
Average for return flights in December 2025
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 12 December 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 3/5

11:55-22:53

2 stops26h 58m

Denver Intl

Mon 18/5

15:58-08:45

2 stops24h 47m

$1,428

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Sun 1/3

19:15-12:37

2 stops35h 22m

Denver Intl

Tue 31/3

16:11-08:20

1 stop23h 09m

$1,591

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Mon 23/2

11:20-17:44

1 stop24h 24m

Denver Intl

Wed 4/3

19:05-09:35

1 stop20h 30m

$1,619

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Sat 24/1

11:20-12:37

1 stop19h 17m

Denver Intl

Sat 31/1

19:05-09:35

1 stop20h 30m

$1,637

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Sun 1/3

11:20-19:33

1 stop26h 13m

Denver Intl

Tue 31/3

13:13-08:05

1 stop25h 52m

$1,660

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Mon 23/2

14:05-22:36

2 stops26h 31m

Denver Intl

Sun 8/3

18:45-06:55

1 stop43h 10m

$1,673

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Tue 13/1

14:15-23:11

1 stop26h 56m

Denver Intl

Tue 27/1

12:46-08:30

2 stops25h 44m

$1,678

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Tue 13/1

12:10-12:23

1 stop18h 13m

Denver Intl

Tue 27/1

15:39-07:00

1 stop21h 21m

$1,678

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Sat 21/3

08:00-12:37

2 stops21h 37m

Denver Intl

Wed 1/4

19:05-08:20

1 stop20h 15m

$1,714

SydneyDenver

SYD - DEN

SYDDEN

Sydney Kingsford Smith

Tue 27/1

21:30-17:26

3 stops37h 56m

$889

Flights are sorted by cheapest return flights first.

Deals found on 10/12

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 5 December 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 18 hours 8 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 $961
Air Canada
Air Canada
From $1,287
United Airlines
United Airlines
From $1,432
Air New Zealand
Air New Zealand
From $1,293

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 December 2025.
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
552 reviews
Check prices

Entertainment

7.5

Overall

8.0

Comfort

8.0

Boarding

8.2

Crew

8.5

Food

7.4

Reviews

1 / 20
8.0
Excellent

Anonymous,Dec 2025

LAX - ORD

Overall good experience with united . I fly united most part so nothing out of obvious i guess
Air New Zealand
8.0
Very Good
552 reviews
Air New Zealand
8.0
Very Good
552 reviews
Check prices

Entertainment

7.5

Overall

8.0

Comfort

8.0

Boarding

8.2

Crew

8.5

Food

7.4

Reviews

1 / 20
8.0
Excellent

Anonymous,Dec 2025

LAX - ORD

Overall good experience with united . I fly united most part so nothing out of obvious i guess
Qantas Airways
7.5
Good
947 reviews
Air New Zealand
8.0
Very Good
552 reviews
Check prices

Entertainment

7.5

Overall

8.0

Comfort

8.0

Boarding

8.2

Crew

8.5

Food

7.4

Reviews

1 / 20
8.0
Excellent

Anonymous,Dec 2025

LAX - ORD

Overall good experience with united . I fly united most part so nothing out of obvious i guess
United Airlines
7.4
Good
9,095 reviews
Air New Zealand
8.0
Very Good
552 reviews
Check prices

Entertainment

7.5

Overall

8.0

Comfort

8.0

Boarding

8.2

Crew

8.5

Food

7.4

Reviews

1 / 20
8.0
Excellent

Anonymous,Dec 2025

LAX - ORD

Overall good experience with united . I fly united most part so nothing out of obvious i guess
Air Canada
7.1
Good
10,516 reviews
Air New Zealand
8.0
Very Good
552 reviews
Check prices

Entertainment

7.5

Overall

8.0

Comfort

8.0

Boarding

8.2

Crew

8.5

Food

7.4

Reviews

1 / 20
8.0
Excellent

Anonymous,Dec 2025

LAX - ORD

Overall good experience with united . I fly united most part so nothing out of obvious i guess

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 $502, however they can be found for as little as $257.

  • 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 (18 hours 8 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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