$54 Cheap flight deals from St. Louis (STL) to Boulder (DEN)

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This Weekend's Flight Deals from St. Louis to Boulder

This weekend's flight prices found within the past 7 days, for the period specified. Prices and availability are subject to change. Additional terms apply.

Sat, May 17 - Sat, May 24
STL
Lambert-St. Louis Intl.
DEN
Denver Intl.
$219 Roundtrip, found 16 hours ago
$219
Roundtrip
found 16 hours ago
Select Frontier Airlines flight, departing Sat, May 17 from Lambert-St. Louis Intl. to Denver Intl., returning Sat, May 24, priced at $219 found 16 hours ago

Airfares from $54 One Way, $103 Round Trip from St. Louis to Boulder

Prices starting at $103 for return flights and $54 for one-way flights to Boulder were the cheapest prices found within the past 7 days, for the period specified. Prices and availability are subject to change. Additional terms apply.

Wed, Jun 4 - Sat, Jun 14
STL
St. Louis
DEN
Denver
$103 Roundtrip, found 4 days ago
$103
Roundtrip
found 4 days ago
Select Frontier Airlines flight, departing Wed, Jun 4 from St. Louis to Denver, returning Sat, Jun 14, priced at $103 found 4 days ago
Wed, May 14 - Tue, May 27
STL
St. Louis
DEN
Denver
$106 Roundtrip, found 6 days ago
$106
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Wed, May 14 from St. Louis to Denver, returning Tue, May 27, priced at $106 found 6 days ago
Tue, Sep 23 - Sat, Sep 27
STL
St. Louis
DEN
Denver
$108 Roundtrip, found 5 hours ago
$108
Roundtrip
found 5 hours ago
Select Frontier Airlines flight, departing Tue, Sep 23 from St. Louis to Denver, returning Sat, Sep 27, priced at $108 found 5 hours ago
Wed, Jun 4 - Fri, Jun 13
STL
St. Louis
DEN
Denver
$109 Roundtrip, found 6 days ago
$109
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Wed, Jun 4 from St. Louis to Denver, returning Fri, Jun 13, priced at $109 found 6 days ago
Wed, Jun 11 - Wed, Jun 18
STL
St. Louis
DEN
Denver
$116 Roundtrip, found 1 hour ago
$116
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Wed, Jun 11 from St. Louis to Denver, returning Wed, Jun 18, priced at $116 found 1 hour ago

Boulder economy flight packages

Price found within the past 48 hours. Click for updated prices.
Wingate by Wyndham Greenwood Village/Denver Tech
2.5-star property

Wingate by Wyndham Greenwood Village/Denver Tech

8.2/10 Very Good! (1,004 reviews)

Jun 20 - Jun 23

3 night stay

St. Louis (STL) to Denver (DEN)

Frontier Airlines • Roundtrip • Coach
per person
found 18 hours ago
North parking area and drive was icy after snow melt.

Reviewed on Feb 25, 2025

Limelight Hotel Denver
4.5-star property

Limelight Hotel Denver

9.4/10 Exceptional! (1,004 reviews)

Jun 20 - Jun 23

3 night stay

St. Louis (STL) to Denver (DEN)

Frontier Airlines • Roundtrip • Coach
Save 100% on your flight
per person
found 17 hours ago
The Staff goes out of their way to make sure your stay is great

Reviewed on Jun 25, 2023

Hilton Denver City Center
4.0-star property

Hilton Denver City Center

8.4/10 Very Good! (1,050 reviews)

Jun 27 - Jun 29

2 night stay

St. Louis (STL) to Denver (DEN)

Frontier Airlines • Coach

Denver (DEN) to St. Louis (STL)

Delta • Coach
per person
found 1 day ago
I enjoyed the stay, and the event I attended there was excellent. However, I think it is unconscionable to charge $65 to valet park when the garage is located down the street from the hotel for a cost of $6.00, but due to weather or if you are leaving in the early morning hours when it is dark and traveling alone (as was I) it is dangerous to have to enter the parking lot alone. I also thought the additional $50 early check in (I arrived at 12/check is at 2:00) was a bit unreasonable.

Reviewed on Aug 12, 2024

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More About Flying To Boulder from St. Louis

Route Information for Flights from St. Louis to Boulder

Origin Airport IATA Code
STL
Destination Airport IATA Code
DEN
Distance
767 mi
Direct Flight Airlines
Air Canada, Southwest Airlines, United Airlines
Earliest Flight Arrival
2:50PM UTC
Latest Flight Arrival
1:20AM UTC

St. Louis to Boulder

Orbitz can provide you with the greatest deals on a wide range of St. Louis to Boulder flights. Orbitz offers guaranteed low prices and offers you the convenience of cutting-edge mobile tools thus providing you with your best travel experience ever.

Mobile Apps for St. Louis to Boulder Flights

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 Budget Flying Made Simple

Finding cheap flights from St. Louis to Boulder is easy with Orbitz. You can pick and choose airlines for your international flights to create inexpensive yet convenient travel arrangements.

Frequently asked questions

Are there non-stop flights from St. Louis to Boulder?
There certainly are. In fact, there are 3 airlines that will fly you directly from Lambert-St. Louis Intl. Airport (STL) to DIA airport. Book your ticket with one of these popular carriers:

  • Southwest Airlines
  • United Airlines
  • Frontier Airlines

What is the shortest flight from St. Louis to Boulder?
It can take as little as 2 hours and 15 minutes to jet from Lambert-St. Louis Intl. Airport (STL) to DEN. Relax and enjoy those window views, because you’ll be landing in a heartbeat.
What airlines fly from St. Louis to Boulder most frequently?
Take a look at Southwest Airlines (WN). This airline offers some of the most frequent flights from STL to Denver, CO (DEN-Denver Intl.). It operates 160 services on this route each month and is a favorite among travelers. Also explore the rewarding deals from United Airlines (UA). Offering 121 flights each month between St. Louis and Boulder, they’ll ensure your journey is just as enjoyable as the destination.
What is the cheapest day of the week to fly?
Consider flying out early in the week to save on your airfare. Orbitz data from 2021 shows that Monday is the cheapest day to depart, followed by Tuesday. Saturday showed the highest average ticket prices likely because many travelers prefer to start their vacation on a weekend.
What is the cheapest month to fly?
We won’t keep you guessing, according to Orbitz data from 2021, the cheapest month to fly is February. Perfect for those who need a weekend getaway, or just a break from it all in the shortest month of the year. Be aware that the most expensive time to fly is during the height of summer in July, and in the holiday month of December.*According to flight demand on Orbitz.com from January to December 2021. Savings are subject to change based on departure location, date and destination.

Fare, taxes & fees: Fares include all taxes and fees, except baggage fees. Rates shown reflect fares found by other Orbitz users over the past 7 days. Due to rapidly changing airline prices & seat availability, these fares may no longer be available.

Refunds/changes/cancellations: Itinerary changes, if permitted for the fare, will have a $30 service fee charged by Orbitz. Additional airline charges may apply.

Other conditions: Schedules, fares and rules are subject to change without notice. Seats are limited and may not be available on all flights/dates or in all markets. Lower fares may be available. Fares will not be honored retroactively or in exchange for any wholly/partially unused ticket. Tickets are non-transferable and non-refundable. Fare rules are provided for the selected itinerary before booking.