$28 Cheap Flights from Denver (DEN) to St. Louis (STL)

View $28 flight on Wed, Mar 4, 2026Opens in a new window

Popular airlines from Denver Intl. Airport (DEN) to St. Louis Lambert Intl. Airport (STL)

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Cheap Flights from Denver to St. Louis (DEN-STL)

Prices were available within the past 7 days and start at $28 for one-way flights and $68 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Wed, Mar 18 - Wed, Mar 25
DEN
Denver
STL
St. Louis
$68 Roundtrip, found 4 hours ago
$68
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Wed, Mar 18 from Denver to St. Louis, returning Wed, Mar 25, priced at $68 found 4 hours ago
Frontier Airlines
Mon, Mar 30 - Sat, Apr 18
DEN
Denver
STL
St. Louis
$71 Roundtrip, found 4 hours ago
$71
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Mon, Mar 30 from Denver to St. Louis, returning Sat, Apr 18, priced at $71 found 4 hours ago
Frontier Airlines
Fri, May 1 - Sat, May 9
DEN
Denver
STL
St. Louis
$72 Roundtrip, found 2 hours ago
$72
Roundtrip
found 2 hours ago
Select Frontier Airlines flight, departing Fri, May 1 from Denver to St. Louis, returning Sat, May 9, priced at $72 found 2 hours ago
Frontier Airlines
Wed, Apr 1 - Wed, Apr 8
DEN
Denver
STL
St. Louis
$77 Roundtrip, found 4 hours ago
$77
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Wed, Apr 1 from Denver to St. Louis, returning Wed, Apr 8, priced at $77 found 4 hours ago
Frontier Airlines
Wed, Mar 11 - Wed, Mar 18
DEN
Denver
STL
St. Louis
$78 Roundtrip, found 4 hours ago
$78
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Wed, Mar 11 from Denver to St. Louis, returning Wed, Mar 18, priced at $78 found 4 hours ago
Frontier Airlines
Sat, Apr 25 - Mon, May 4
DEN
Denver
STL
St. Louis
$81 Roundtrip, just found
$81
Roundtrip
just found
Select Frontier Airlines flight, departing Sat, Apr 25 from Denver to St. Louis, returning Mon, May 4, priced at $81 just found
United
Sat, Apr 25 - Sat, May 2
DEN
Denver
STL
St. Louis
$157 Roundtrip, found 4 hours ago
$157
Roundtrip
found 4 hours ago
Select United flight, departing Sat, Apr 25 from Denver to St. Louis, returning Sat, May 2, priced at $157 found 4 hours ago
Southwest Airlines
Wed, Apr 22 - Sat, Apr 25
DEN
Denver
STL
St. Louis
$168 Roundtrip, found 13 hours ago
$168
Roundtrip
found 13 hours ago
Select Southwest Airlines flight, departing Wed, Apr 22 from Denver to St. Louis, returning Sat, Apr 25, priced at $168 found 13 hours ago
Delta
Sat, May 9 - Sat, May 16
DEN
Denver
STL
St. Louis
$187 Roundtrip, found 4 hours ago
$187
Roundtrip
found 4 hours ago
Select Delta flight, departing Sat, May 9 from Denver to St. Louis, returning Sat, May 16, priced at $187 found 4 hours ago
American Airlines
Mon, Mar 30 - Sat, Apr 4
DEN
Denver
STL
St. Louis
$215 Roundtrip, just found
$215
Roundtrip
just found
Select American Airlines flight, departing Mon, Mar 30 from Denver to St. Louis, returning Sat, Apr 4, priced at $215 just found

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Alternative airports near St. Louis

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $123
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $123

Find the cheapest month to fly from Denver (DEN) to St. Louis (STL)

January is typically the cheapest month to fly

From $58 - $193 per traveler.
Flights from Denver (DEN) to St. Louis (STL)
Origin airport
Denver Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, United
Roundtrip price
$60
Distance
767 mi
Average flight time
3 hours 1 min

Denver to St. Louis Flights

The cheapest times to fly from Denver to St. Louis

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Denver to St. Louis are during the month of March. You can find some of the cheapest flights from Denver to St. Louis with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Denver to St. Louis

Sunday is one of the best days to book for cheap flights from Denver to St. Louis: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Denver to St. Louis

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Denver to St. Louis in 2026. You can also book with separate airlines for your outbound and return journeys, from $28 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Denver to St. Louis flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Denver to St. Louis airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) cost?
You can find cheap one-way flights from $28 and cheap return flights from $68 Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) with Expedia. One-way flights typically cost between $150 and $774, and return flights often range between $201 and $946. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) ticket fares go up or down.*Typical price ranges based on flights available on Expedia in the last year. Prices include multi-airline options.
What is the cheapest month to fly from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
September is the cheapest month to fly from Denver, CO (DEN) to St. Louis, MO (STL), with average return fares around $275. This fare is about 15% lower than the average price throughout the year, as September typically sees a decrease in travel demand. Other economical months for this route include August and October.*Averages based on flights available on Expedia in the last year.
Which airlines fly direct from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
There are 2 airlines offering direct flights from DEN to STL:

  • United operates around 28 direct flights from DEN to STL every week
  • Frontier Airlines operates around 7 direct flights from DEN to STL every week

What is the cheapest airline that flies from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Frontier Airlines is one of the cheapest airlines offering nonstop flights from Denver, CO (DEN) to St. Louis, MO (STL), with round-trip tickets starting from around $48. Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.*Prices based on flights available on Expedia in the last year.
How do I find cheap flights from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
To find a cheap flight from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best airline to fly with from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The best airline to fly with from Denver, CO (DEN) to St. Louis, MO (STL) will differ from traveler to traveler. If you like to fly early, WN offers early morning flights. If price is the most important factor, Frontier Airlines typically offers the lowest fares. WN offers the most daily flights from DEN to STL, which is great if flexibility is what you value most. The best carrier for this journey could also be the one you have a loyalty membership with, as flying with that airline or another airline within the same alliance could help you collect points or enjoy lounge access.
What is the best time to fly from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
For flights from Denver (DEN) to St. Louis (STL), September and August are the best months to fly. These months provide the lowest average return flight prices at around $275, making them a great choice for travelers looking to visit St. Louis at a reasonable cost.*Prices based on flights available on Expedia in the last year.
How many flights per day from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
On average, there are around 11 nonstop flights per day from Denver Intl. (DEN) to Lambert-St. Louis Intl. (STL). For more options, look at flights that include layovers.
What is the earliest flight from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The earliest flight from Denver International Airport (DEN) to Lambert-St. Louis International Airport (STL) typically departs at around 12:00 AM, operated by Frontier Airlines. This seasonal service is available in August, September, and October, allowing you to maximize your time in St. Louis. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What are the most popular departure times for flights from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The most popular departure times for flights from Denver (DEN-Denver Intl.) to St. Louis (STL-Lambert-St. Louis Intl.) are in the early morning, from 6am to 9am. About 24% of passengers prefer this time window. Many major carriers, including American Airlines, Southwest Airlines, and Frontier Airlines, offer flights during this window. This timing is popular because it allows you to arrive in St. Louis with a full day ahead of you.
How long does it take to fly from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Flying nonstop from DEN to STL takes around 2 hours, with the route covering approximately 768 miles. Flights with a layover typically take 3 hours 50 minutes longer than direct options. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
You can fly first class between DEN and STL. First class cabins are available on:

  • Delta Air Lines
  • American Airlines
  • United Airlines

How much is a business class flight from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
A direct, return business class ticket from Denver, CO (DEN) to St. Louis, MO (STL) typically costs between $911 - $1,454 per adult. Prices often fluctuate based on seasonality and how early you book. You may also be able to find a cheaper business class journey between Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) if you opt for a connecting flight.*Prices based on flights available on Expedia in the last year.
How do I earn miles on a Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight with Expedia?
It's easy to earn miles on a Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for St. Louis from Denver Intl. (DEN)?
If you're planning to travel to St. Louis from Denver Intl. (DEN), you can fly into Lambert-St. Louis Intl. (STL) Some flights may connect through major hubs like Portland Intl. (PDX), Love Field (DAL), Eppley Field (OMA) before reaching St. Louis. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) at the last minute?
Typically, booking a last minute flight from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight and hotel package?
Securing a Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) St Louis Vacation Packages is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
If you booked your Denver, CO (DEN-Denver Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

*Flight schedules are subject to change.

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