DEN - STL

$43 Find Cheap Flights from Denver to St. Louis

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Denver to St. Louis departing on 4/4. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to St. Louis

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Denver to St. Louis, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Denver to St. Louis, as well as popular online travel agencies
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41.299.237 searches in the past 7 days on KAYAK

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Everything you should know

Cheapest round-trip
$105
Overall average: $277
Frontier
Mon 4/6Wed 4/8
DEN - STL • Non-stop
Cheapest one-way
$43
Typical prices: $110-$193
Frontier
Sat 4/4
DEN - STL • Non-stop
Advice from real travelers
AI-powered summary based on content written by travel experts. AI can make mistakes.
United's Wi-Fi includes free messaging on most flights.
Southwest offers two free checked bags for family travel.
Expert advice
Expert advice
Expert advice
Expert advice
Nonstop flights
You can fly direct with Frontier, Southwest and United Airlines. Average duration is 2h 07m
Direct flights
Direct flights
+1
+1
Direct flights
Direct flights
+1
When to book
in advance
Our data shows that travelers who book at least 2 weeks in advance save around 17% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 33% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to St. Louis!
Flight Deals
Booking Insights
Expert advice
Flight Deals

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

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Denver to St. Louis that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Denver to St. Louis

Mon, Apr 6 - Wed, Apr 8
Frontier Logo
6:40 am - 9:48 am
DEN
-
STL
2h 08mnonstop
Frontier Logo
8:16 pm - 9:49 pm
STL
-
DEN
2h 33mnonstop
$105Frontier
Wed, Apr 8 - Fri, Apr 10
Frontier Logo
6:40 am - 9:48 am
DEN
-
STL
2h 08mnonstop
Frontier Logo
8:16 pm - 9:49 pm
STL
-
DEN
2h 33mnonstop
$106Frontier
Wed, Apr 8 - Wed, Apr 8
Frontier Logo
6:40 am - 9:48 am
DEN
-
STL
2h 08mnonstop
Frontier Logo
8:16 pm - 9:49 pm
STL
-
DEN
2h 33mnonstop
$112Frontier
Fri, May 1 - Mon, May 4
Frontier Logo
4:09 pm - 7:21 pm
DEN
-
STL
2h 12mnonstop
Frontier Logo
8:17 pm - 9:50 pm
STL
-
DEN
2h 33mnonstop
$120Frontier
Fri, Apr 24 - Mon, Apr 27
Frontier Logo
4:09 pm - 7:21 pm
DEN
-
STL
2h 12mnonstop
Frontier Logo
8:17 pm - 9:50 pm
STL
-
DEN
2h 33mnonstop
$123Frontier
Fri, Apr 10 - Mon, Apr 13
Frontier Logo
10:40 pm - 12:21 pm
DEN
-
STL
12h 41m
1 stop
Frontier Logo
8:19 pm - 9:52 pm
STL
-
DEN
2h 33mnonstop
$129Frontier
Mon, Jun 1 - Wed, Jun 3
Frontier Logo
4:15 pm - 7:23 pm
DEN
-
STL
2h 08mnonstop
Frontier Logo
8:08 pm - 9:41 pm
STL
-
DEN
2h 33mnonstop
$130Frontier
Fri, May 1 - Mon, May 4
Frontier Logo
4:09 pm - 7:21 pm
DEN
-
STL
2h 12mnonstop
Frontier Logo
8:17 pm - 9:50 pm
STL
-
DEN
2h 33mnonstop
$132Frontier
Fri, May 8 - Mon, May 18
Frontier Logo
4:15 pm - 7:23 pm
DEN
-
STL
2h 08mnonstop
Frontier Logo
3:02 pm - 8:52 pm
STL
-
DEN
6h 50m
1 stop
$133Frontier
Sat, May 9 - Tue, May 19
Frontier Logo
4:15 pm - 7:23 pm
DEN
-
STL
2h 08mnonstop
Frontier Logo
6:51 pm - 3:25 am
STL
-
DEN
9h 34m
1 stop
$134Frontier
Booking Insights

KAYAK's insights & trends for Denver to St. Louis flights

Get data-powered insights and trends into flights from Denver to St. Louis to help you find the cheapest flights, the best time to fly and much more.

What’s the cheapest day of the week to fly from Denver to St. Louis?

The average price of all round-trip flights from Denver to St. Louis clicked on KAYAK for each day over the last 12 months.

When flying from Denver to St. Louis, you should consider leaving on a Friday and avoid Tuesdays if you are looking for the best rates. For your return to Denver, you’ll find the best rates on Wednesdays and the most expensive ones on Sundays.

What is the cheapest month to fly from Denver to St. Louis?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Denver to St. Louis, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Denver to St. Louis is January, where tickets cost $166 (return) on average. On the other hand, the most expensive months are June and March, where the average cost of round-trip tickets is $304 and $299 respectively.

How far in advance should I book a flight from Denver to St. Louis?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Denver to St. Louis, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Denver to St. Louis, you should book around 2 weeks before departure, which saves you about 17% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 11 weeks before departure.

Expert advice

Expert advice for your flight from Denver to St. Louis

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Stefanie Waldek

Stefanie Waldek

Expert on Frontier and United Airlines

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Blane Bachelor

Blane Bachelor

Expert on Southwest

Blane Bachelor is a journalist and editor specializing in travel and aviation who writes regularly for top global outlets. Born and raised in Florida, Blane has worked and lived in four countries, including the Netherlands, where she’s currently based with her family. Her favorite way to get to know a new destination is by running or riding a bike around town – or hearing a spooky ghost story about local history. She will always choose the window seat.

Yulia Denisyuk

Yulia Denisyuk

Expert on STL

Yulia is a freelance journalist who’s dispatched from 90+ countries. Her work focuses on cultures, adventure trips and air travel, appearing in NatGeo, NYT, CNTraveler, and more. For past assignments, she’s stayed with nomads in Mongolia and learned the art of Imigongo in Rwanda. She’s based in Chicago; in winter she often questions that decision.

Harriet Baskas

Harriet Baskas

Expert on DEN

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Good to know

Low seasonJanuary
Cheapest flight$43
Best time to beat the crowds with an average 33% drop in price.
Most popular time to fly with an average 12% increase in price.
Flight from Denver to St. Louis

When to book flights from Denver to St. Louis

Are your dates flexible? Find out the best times to travel from Denver to St. Louis based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Denver to St. Louis

  • Can I fly nonstop from Denver International Airport (DEN) to Lambert St Louis Airport (STL)?

    Yes, direct flights exist between Denver International Airport and Lambert St. Louis Airport. Multiple carriers, like Southwest Airlines and United Airlines, provide direct flights from DEN to Lambert Airport if you want to reach your destination quickly.

  • Is there public transportation to downtown from Lambert St Louis Airport?

    Yes, there is public transportation from Lambert St Louis to downtown. There are multiple options such as train, bus, or even taxi. Services run daily and leave every 20min. The travel time is roughly 30min.

  • Are there hotels at Lambert St Louis?

    Yes, there are quite a few hotel alternatives at and in close proximity to Lambert International Airport in St. Louis, including Hampton Inn St. Louis Airport and the Comfort Inn & Suites St. Louis-Hazelwood.

  • How can I get from one terminal to the other?

    STL Airport has a free 24h Terminal Shuttle that operates between Exit 12 at both terminals. There is currently no way to walk between terminals. Terminal 1 and Terminal 2 are less than one mile apart, thus the shuttle trip duration is roughly 10min. Every 8 to 15min, shuttles are scheduled to pick up passengers.

  • What is the cheapest flight from Denver to St. Louis?

    In the last 3 days, the lowest price for a flight from Denver to St. Louis was $43 for a one-way ticket and $105 for a round-trip.

  • Do I need a passport to fly between Denver and St. Louis?

    Even though you are not required to have a passport, keep in mind that an official ID is needed to board the airplane.

  • Which airlines offer Wi-Fi service onboard planes from Denver to St. Louis?

    JetBlue, Delta, and American Airlines offer inflight Wi-Fi service on the Denver to St. Louis flight route.

  • Which aircraft models fly most regularly from Denver to St. Louis?

    The Boeing 737 MAX 8 is the aircraft model that flies most regularly on the Denver to St. Louis flight route.

  • Which airline alliances offer flights from Denver to St. Louis?

    Star Alliance is the only airline alliance operating flights between Denver and St. Louis.

  • On which days can I fly direct from Denver to St. Louis?

    There are nonstop flights from Denver to St. Louis on a daily basis.

  • Which is the best airline for flights from Denver to St. Louis, Southwest or United Airlines?

    The two airlines most popular with KAYAK users for flights from Denver to St. Louis are Southwest and United Airlines. With an average price for the route of $317 and an overall rating of 8.0, Southwest is the most popular choice. United Airlines is also a great choice for the route, with an average price of $322 and an overall rating of 7.4.

  • How does KAYAK find such low prices on flights from Denver to St. Louis?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Denver to St. Louis.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Denver to St. Louis?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Louis from Denver is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Denver to St. Louis?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to St. Louis with an airline and back to Denver with another airline. Booking your flights between Denver and STL can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Denver to St. Louis?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to St. Louis from Denver up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Denver to St. Louis

  • Looking for a cheap flight? 25% of our users found flights on this route for $162 or less one-way and $195 or less round-trip.
  • Utilize the offered lounges at the departure and arrival airports. There are about six lounges at Denver International Airport (DEN) and a number of lounges at Lambert St. Louis (STL) that provide free food, drinks, showers, and high-speed Wi-Fi, among other services.
  • If you are departing from Denver International Airport (DEN) and need parking, there are numerous alternatives. You may use Valet Parking, which offers the best prices and reservations or choose one of the indoor or outdoor self-parking choices. They offer a range of amenities, including 24h staff and shuttles, wider, angled parking, free EV charging, and free roses.
  • When flying out of Denver International Airport, it is suggested that you arrive at the airport 2h before your flight's scheduled departure time. This should provide you with plenty of time to check-in for your flight, go through security, and make your way to your gate. If you visit the DEN website before you leave, you will be able to observe the wait times for the security lines in real-time, which will allow you to better prepare for your trip. Every single security checkpoint inside the DEN is always open and performing appropriately.
  • Free assistance for passengers traveling with wheelchairs is offered by airlines at both Denver International Airport (DEN) and Lambert St. Louis Airport (STL). Travelers with limited mobility or elderly passengers may find this to be of great assistance. Contacting the airline in advance to request a passenger help agent will get you the finest possible accommodations.
  • If you need to convert money at Lambert St Louis, go to the lower level of Terminal 1 and find the currency exchange counter near the C Gates security checkpoint. US Bank has a branch at the airport that provides comprehensive banking services as well as a currency exchange for international travelers. The business is open from Monday through Friday, starting at 8 am and closing at 5 pm.

Prefer to fly direct from Denver to St. Louis?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Denver Intl to Lambert-St Louis.
Find which airlines fly direct from Denver Intl Airport to Lambert-St Louis Airport, which days they fly and book direct flights.

Direct departures

Denver Intl to Lambert-St Louis

Monday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Tuesday

Southwest,United Airlines,Frontier

Southwest,United Airlines, +1 more

Wednesday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Thursday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Friday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Saturday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Sunday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

See more direct flights

Direct returns

Lambert-St Louis to Denver Intl

Monday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Tuesday

Southwest,United Airlines,Frontier

Southwest,United Airlines, +1 more

Wednesday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Thursday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Friday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Saturday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

Sunday

Frontier,Southwest,United Airlines

Frontier,Southwest, +1 more

See more direct flights

Reviews of the top 3 airlines serving from Denver to St. Louis

 
See real verified KAYAK customer reviews for airlines flying from Denver to St. Louis. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Denver to St. Louis? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4321 reviews
7.5Entertainment
8.0Comfort
8.1Boarding
7.0Food
8.6Crew
Airline reviews

We had a 5 hour delay on the tarmac in Baltimore

2.0 MediocreDavid, Mar 2026
ALB - BWI
Read more Southwest reviews

We had a 5 hour delay on the tarmac in Baltimore

Long layover between flights to Long Island from BWI - need better coordination between flights

I elected to pay for the upgrades and found very little difference

The new seating arrangement is so over priced for what you get.

The problem with the seat assignments is that there were a lot of rows in the front that were empty but my row at the back was full. Just not so pleasant.

No food or entertainment, just a quick 40 minute flight. A little bumpy due to Santa Ana winds but pilot has no control over that. Good flight and landing!

Good but I prefer choose your own seat. With the new assigned seats they should board from the back I see no advantage to this new boarding. Just like every other airline

I realize they are still working out kinks with the new boarding process, but by the time I boarded in group 5, most of the bins were full. All airlines should better enforce small bags and jackets going under the seats until everyone has boarded.

WiFi was not working and didn’t have a beverage service

I have not flown Southwest in awhile and had a very pleasant experience. From ticketing to boarding to the flight. The flight left on time and landed ahead of schedule. It won't be so long next time!!

Flight left on time and we arrived 25 minutes early! There was a gate available when we arrived so early on a busy Sunday afternoon! Flight attendants came around twice with the drinks cart.

Airport terminal was outdated, flight was on a small jet with no wifi

Sitting on the runway after we land for almost two hours! Not sure if we should blame United or Just Dumpy Vance.

Flight was late - I was downgraded from first class to coach

Excellent flight. Smooth, efficient boarding. Quick flight. Arrived early at STL.

Crew seemed a bit cranky. No seatback screens. But boarding was efficient and on time and we arrived early.

See previous note about the passenger in Denver who threw my husband's bag out of the overhead bin in order to maker room for his own. And the flight attendant back up the new passenger.

Terrible. They wouldn't allow me on my flight on the 14th..

Impressed with the service despite turbulence because of the weather. Both flights arrived before their scheduled times.

Great experience…left a bit behind schedule but made up fir that in the air and landed 10 minutes early 😁

My flight was originally from SAT to MCO connecting from MCO to ORD. We got diverted to ATL and than Frontier staff there was sooo un helpful first they said they couldn’t give us any accommodation since our flight first got delayed that cancelled and now it’s 221am and I am still in ATL since they said they need to create a new flight my final destination is ORD and I have been delayed twice and cancelled. With no real help the frontier app didn’t work no email updates over all such a horrible experience

There's no seats that lean back with little leg space i wad uncomfortable the entire flight. Your charges for extra baggage is despicable and costly!!

Remind customers of the need to have passport or new ID for boarding.

Flight was canceled. Most upsetting was message from Kayak, stating that the flight was canceled and click with Kayak for details regarding rebook, refund details. THERE'S NO INFORMATION PROVIDED BY KAYAK EXCEPT THAT FLIGHT IS CANCELED. AND NOW THIS SURVEY TO FIND OUT HOW WAS THE FLIGHT !!!!!!!

The flight never took off and we spent 7 hours at the airport

Gate not determined until I got to the airport - hard to plan the trip to the airport.

Our flight was canceled. I will never use Kayak nor Frontier for travel again. The entire experience was a headache.

Frontier.. nickel and dime add-ons. Flight late, on time, late again, last minute gate change, arrival gate required a shuttle to the terminal. They sure keep you guessing.. if you like a little chaos and airport anxiety, this is the airline for you!

This is my second time flying with Frontier. My current experience was very favorable. The staff from the gate to the plane was friendly, warm and professional. The food options lacked in my opinion. This area needs some attention in my opinion.

There was no food and no entertainment, so I'm not sure why these are even in the survey, as my understanding is frontier does not ever offer food without a few, not even a snack, and there are no screens so unless the flight safety talk is our entertainment why ask how we liked it?. One of the flight attendants say in the back of the plane as people filed in to their seats, yelling orders about where to put baggage and telling people to hurry up. It was the least professional experience I've ever had on a flight.

Everything you need to know for your flight from Denver to St. Louis

Other airlines flying from Denver to St. Louis

Flights from the other most popular airlines that fly from Denver to St. Louis according to KAYAK users. Prices are the lowest found on KAYAK over the last 7 days. Price and availability are not guaranteed.