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C$ 206+ 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 18/12. Fares are subject to change and may not be available on all flights or dates of travel.
— DEN
27 Nov — 4 Dec1
1 adult
1 adult, Economy, 0 bags

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 629,999 searches and data was last updated on 28 October 2025.

Round-trip from

C$ 487

One-way from

C$ 206

Popular in

December

Cheapest in

November

Average price

C$ 664
11/11-14/11
  • 11/11-14/11
  • 3 total stops
  • 28h 19m total
  • Toronto to Denver
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18/12
  • 18/12
  • 1 total stop
  • 20h 23m total
  • Toronto to Boulder
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Highest demand for flights based on searches. 3% potential increase in price (C$ 21 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease (C$ 12 potential savings vs. average RT price).
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Average for round-trip flights in October 2025
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Find flight deals to Boulder

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 October 2025.

Tue 11/1112:40 p.m.YYZ - DEN
1 stop9h 25mMultiple Airlines
Fri 14/1112:59 a.m.DEN - YYZ
2 stops18h 54mMultiple Airlines
Deal found 25/10C$ 487
Wed 10/129:35 a.m.YYZ - DEN
1 stop29h 12mMultiple Airlines
Tue 30/1210:46 a.m.DEN - YYZ
2 stops22h 57mMultiple Airlines
Deal found 27/10C$ 490
Mon 17/117:55 p.m.YYZ - DEN
1 stop10h 04mMultiple Airlines
Mon 24/119:44 a.m.DEN - YYZ
2 stops19h 14mMultiple Airlines
Deal found 28/10C$ 492
Fri 19/127:55 p.m.YYZ - DEN
1 stop10h 03mMultiple Airlines
Mon 5/16:21 p.m.DEN - YYZ
1 stop10h 26mMultiple Airlines
Deal found 27/10C$ 494
Tue 11/119:15 a.m.YTZ - DEN
1 stop12h 44mMultiple Airlines
Fri 14/1112:59 a.m.DEN - YTZ
2 stops16h 51mMultiple Airlines
Deal found 25/10C$ 495
Tue 25/1112:40 p.m.YYZ - DEN
1 stop17h 18mMultiple Airlines
Tue 2/1210:50 a.m.DEN - YYZ
2 stops35h 21mMultiple Airlines
Deal found 27/10C$ 495
Mon 1/121:30 p.m.YYZ - DEN
2 stops16h 28mMultiple Airlines
Sun 7/125:35 p.m.DEN - YYZ
1 stop10h 45mMultiple Airlines
Deal found 27/10C$ 497
Fri 19/127:55 p.m.YYZ - DEN
1 stop10h 03mMultiple Airlines
Tue 6/111:59 p.m.DEN - YYZ
1 stop12h 17mMultiple Airlines
Deal found 27/10C$ 498
Tue 11/119:15 a.m.YTZ - DEN
1 stop12h 44mMultiple Airlines
Sun 16/118:44 p.m.DEN - YTZ
1 stop20h 13mMultiple Airlines
Deal found 25/10C$ 501
Wed 17/129:35 a.m.YYZ - DEN
1 stop20h 23mMultiple Airlines
Mon 5/16:21 p.m.DEN - YYZ
1 stop10h 26mMultiple Airlines
Deal found 27/10C$ 501
Fri 14/119:15 a.m.YTZ - DEN
1 stop7h 01mMultiple Airlines
Mon 17/118:05 a.m.DEN - YTZ
1 stop8h 52mMultiple Airlines
Deal found 28/10C$ 502
Mon 24/117:55 p.m.YYZ - DEN
1 stop10h 03mMultiple Airlines
Mon 1/126:24 p.m.DEN - YYZ
1 stop9h 56mMultiple Airlines
Deal found 27/10C$ 502

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 629,999 searches and data was last updated on 28 October 2025.
Use the filters below to find and compare flights to Boulder that are best for you.

Fly from

Toronto

Route

Depart

Return

Price

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Tue 11/11

9:15 a.m.-7:59 p.m.

1 stop12h 44m

Denver Intl

Fri 14/11

12:59 a.m.-7:50 p.m.

2 stops16h 51m

C$ 495

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Tue 11/11

9:15 a.m.-7:59 p.m.

1 stop12h 44m

Denver Intl

Sun 16/11

8:44 p.m.-6:57 p.m.

1 stop20h 13m

C$ 501

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Fri 14/11

9:15 a.m.-2:16 p.m.

1 stop7h 01m

Denver Intl

Mon 17/11

8:05 a.m.-6:57 p.m.

1 stop8h 52m

C$ 502

TorontoDenver

YYZ - DEN

YYZDEN

Toronto Pearson Intl

Sun 15/2

8:00 p.m.-9:04 a.m.

1 stop15h 04m

Denver Intl

Tue 24/2

7:33 a.m.-7:55 p.m.

1 stop10h 22m

C$ 502

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Mon 24/11

9:15 a.m.-5:22 p.m.

1 stop10h 07m

Denver Intl

Mon 1/12

8:45 p.m.-1:42 p.m.

1 stop14h 57m

C$ 505

TorontoDenver

YYZ - DEN

YYZDEN

Toronto Pearson Intl

Thu 8/1

6:00 a.m.-3:16 p.m.

1 stop11h 16m

Denver Intl

Sun 11/1

6:23 a.m.-3:50 p.m.

1 stop7h 27m

C$ 513

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Mon 10/11

9:15 a.m.-2:16 p.m.

1 stop7h 01m

Denver Intl

Fri 14/11

12:59 a.m.-7:50 p.m.

2 stops16h 51m

C$ 533

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Tue 2/12

7:40 p.m.-10:18 a.m.

2 stops16h 38m

Denver Intl

Thu 4/12

8:45 p.m.-1:42 p.m.

1 stop14h 57m

C$ 533

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Mon 17/11

9:15 a.m.-9:28 p.m.

2 stops14h 13m

Denver Intl

Sun 23/11

6:22 a.m.-8:20 a.m.

1 stop23h 58m

C$ 538

TorontoDenver

YTZ - DEN

YTZDEN

Toronto Island

Mon 10/11

9:15 a.m.-2:16 p.m.

1 stop7h 01m

Denver Intl

Sun 16/11

8:44 p.m.-6:57 p.m.

1 stop20h 13m

C$ 541

Flights are sorted by cheapest round-trip flights first.

Deals found on 26/10

Showing 1-10 of 60 results
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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 round-trip 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 round-trip flight from Toronto to Boulder. Price data was last updated on 24 October 2025.

Booking 85 days in advance of your planned departure date is, on average, the best time to get cheap flights to Boulder. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

How long is the flight to Boulder?

On average, a flight from Toronto to Boulder takes 11 hours 9 minutes. Flights to Boulder from other popular cities in Canada will vary in length. Below are a few examples of popular routes and their flight times.

Weekly flight availability to Boulder

The most flights from Toronto to Boulder are scheduled on a Monday (4 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (3 on average).

What are the most popular airlines that fly to Boulder?

The most popular airlines flying from Toronto to Boulder are Air Canada, United Airlines and WestJet.

Air Canada
Air Canada
From C$ 89
United Airlines
United Airlines
From C$ 192
WestJet
WestJet
From C$ 170
Alaska Airlines
Alaska Airlines
From C$ 434

What are the cheapest airlines that fly to Boulder?

The cheapest airlines flying from Toronto to Boulder are WestJet, Air Canada and United Airlines.

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 October 2025.
Check out reviews from past customers who have flown United Airlines,WestJet, andAir Canada to the United States to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
United Airlines
7.4
Good
9,001 reviews
Check prices

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

Boarding

7.7

Crew

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Oct 2025

YUL - ORD

Crew and customer service are 5 stars. I had a lot of luggage for a very long trip and they were nothing but helpful and found solutions to every problem. It was my first time flying with United, and they really are the friendly skies. Leg room however, on 2/3 flights was terrible. Same for entertainment: There was only a seat-mounted screen on 1/3 flights. It would have been nice to have on the longest leg of the journey.
United Airlines
7.4
Good
9,001 reviews
United Airlines
7.4
Good
9,001 reviews
Check prices

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

Boarding

7.7

Crew

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Oct 2025

YUL - ORD

Crew and customer service are 5 stars. I had a lot of luggage for a very long trip and they were nothing but helpful and found solutions to every problem. It was my first time flying with United, and they really are the friendly skies. Leg room however, on 2/3 flights was terrible. Same for entertainment: There was only a seat-mounted screen on 1/3 flights. It would have been nice to have on the longest leg of the journey.
WestJet
7.2
Good
3,148 reviews
United Airlines
7.4
Good
9,001 reviews
Check prices

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

Boarding

7.7

Crew

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Oct 2025

YUL - ORD

Crew and customer service are 5 stars. I had a lot of luggage for a very long trip and they were nothing but helpful and found solutions to every problem. It was my first time flying with United, and they really are the friendly skies. Leg room however, on 2/3 flights was terrible. Same for entertainment: There was only a seat-mounted screen on 1/3 flights. It would have been nice to have on the longest leg of the journey.
Air Canada
7.1
Good
10,371 reviews
United Airlines
7.4
Good
9,001 reviews
Check prices

Overall

7.4

Entertainment

7.1

Comfort

7.3

Food

6.6

Boarding

7.7

Crew

8.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Oct 2025

YUL - ORD

Crew and customer service are 5 stars. I had a lot of luggage for a very long trip and they were nothing but helpful and found solutions to every problem. It was my first time flying with United, and they really are the friendly skies. Leg room however, on 2/3 flights was terrible. Same for entertainment: There was only a seat-mounted screen on 1/3 flights. It would have been nice to have on the longest leg of the journey.

FAQs about flying to Boulder

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

    Yes, flights with layovers 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, WestJet is rated the highest out of the airlines that fly to Boulder.

  • How much is a round-trip flight to Boulder?

    A round-trip flight to Boulder will typically cost around C$ 345, however they can be found for as little as C$ 80.

  • Where does the fastest flight to Boulder depart from?

    For those looking to save time traveling to Boulder, Regina offers the quickest one-way flight (2 hours 13 minutes).

  • Does Denver Intl have rental cars?

    Yes. Those touching down at Denver Intl can take advantage of the rental car 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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