DEN - STL

$28 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 1/7. 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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Everything you should know

Cheapest round-trip
$102
Overall average: $179
Frontier
Fri 1/9Mon 1/12
DEN - STL • Non-stop
Cheapest one-way
$28
Typical prices: $67-$408
Frontier
Wed 1/7
DEN - STL • Non-stop
Our travelers' advice
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
Video guide: How to find cheap flights to St. Louis
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When to book
3 weeks
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 21% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
January
Cheapest • 24% price drop
December
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

Fri, Jan 9 - Mon, Jan 12
Frontier Logo
6:50 am - 10:02 am
DEN
-
STL
2h 12mnonstop
Frontier Logo
7:43 pm - 9:15 pm
STL
-
DEN
2h 32mnonstop
$102Frontier
Fri, Jan 9 - Mon, Jan 12
Frontier Logo
6:50 am - 10:02 am
DEN
-
STL
2h 12mnonstop
Frontier Logo
7:43 pm - 9:15 pm
STL
-
DEN
2h 32mnonstop
$104Frontier
Wed, Jan 7 - Thu, Jan 8
Frontier Logo
6:50 am - 10:02 am
DEN
-
STL
2h 12mnonstop
Frontier Logo
3:43 pm - 9:38 pm
STL
-
DEN
6h 55m1 stop
$109Frontier
Thu, Jan 22 - Sat, Jan 24
Frontier Logo
10:29 pm - 12:08 pm
DEN
-
STL
12h 39m1 stop
Frontier Logo
3:46 pm - 5:23 pm
STL
-
DEN
2h 37mnonstop
$110Frontier
Mon, Jan 12 - Fri, Jan 16
Frontier Logo
12:05 am - 6:51 am
DEN
-
STL
29h 46m1 stop
Frontier Logo
7:27 pm - 8:59 pm
STL
-
DEN
2h 32mnonstop
$117Frontier
Thu, Jan 8 - Mon, Jan 12
Frontier Logo
10:29 pm - 12:12 pm
DEN
-
STL
12h 43m1 stop
Frontier Logo
7:43 pm - 9:15 pm
STL
-
DEN
2h 32mnonstop
$121Frontier
Fri, Jan 23 - Mon, Jan 26
Frontier Logo
3:38 pm - 6:44 pm
DEN
-
STL
2h 06mnonstop
Frontier Logo
9:45 pm - 10:32 am
STL
-
DEN
13h 47m1 stop
$125Frontier
Fri, Jan 16 - Mon, Jan 19
Frontier Logo
6:13 pm - 6:51 am
DEN
-
STL
11h 38m1 stop
Frontier Logo
7:36 pm - 9:08 pm
STL
-
DEN
2h 32mnonstop
$126Frontier
Thu, Jan 22 - Sat, Jan 24
Frontier Logo
4:07 pm - 11:33 pm
DEN
-
STL
30h 26m2 stops
Frontier Logo
3:46 pm - 5:23 pm
STL
-
DEN
2h 37mnonstop
$129Frontier
Fri, Jan 16 - Mon, Jan 19
Frontier Logo
6:13 pm - 6:51 am
DEN
-
STL
11h 38m1 stop
Frontier Logo
7:36 pm - 9:08 pm
STL
-
DEN
2h 32mnonstop
$130Frontier
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.

Find cheap flights to St. Louis
Find cheap flights to St. Louis

Planning a trip from Denver to St. Louis? KAYAK’s data-powered insights will help you find cheap flights. Learn the best time to fly, how early to book your ticket, and other tips to secure great prices.

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 Sundays 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 $179 (return) on average. On the other hand, the most expensive months are June and December, where the average cost of round-trip tickets is $297 and $279 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 3 weeks before departure, which saves you about 21% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 19 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.
Airlines
Frontier

Avoid airport check-in fees by using the Frontier app or kiosk for free check-in.


Purchase priority boarding to ensure overhead bin space for your carry-on.

Southwest

Southwest offers free carry-on and personal item, but checked bags now incur fees.


Southwest's Rapid Rewards program offers unlimited rewards seats and no blackout dates.

United Airlines

United offers Wi-Fi on most flights, with free messaging available.


Economy Plus seats provide up to six inches more legroom than standard economy.

Airports
DEN

Use the West Security Checkpoint at DEN for faster screening; it allows liquids and laptops to stay in bags.

STL

Take the MetroLink Red Line from STL for easy access to downtown St. Louis and popular areas like Delmar Loop.

Our travel experts
Stefanie Waldek

Stefanie Waldek

Expert on Frontier and United Airlines

Stefanie Waldek

Stefanie Waldek

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.

Read more
Blane Bachelor

Blane Bachelor

Expert on Southwest

Blane Bachelor

Blane Bachelor

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.

Read more
Yulia Denisyuk

Yulia Denisyuk

Expert on STL

Yulia Denisyuk

Yulia Denisyuk

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.

Read more
Harriet Baskas

Harriet Baskas

Expert on DEN

Harriet Baskas

Harriet Baskas

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.

Read more

Good to know

Low seasonNovember
Cheapest flight$28
Best time to beat the crowds but there is an average 9% increase in price.
Most popular time to fly with an average 18% 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 $28 for a one-way ticket and $102 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, American Airlines, and Alaska 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 $301 and an overall rating of 7.9, Southwest is the most popular choice. United Airlines is also a great choice for the route, with an average price of $325 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 $73 or less one-way and $188 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

Southwest, United Airlines

Wednesday

Frontier, Southwest, United Airlines

Frontier, Southwest, +1 more

Thursday

Southwest, United Airlines

Southwest, United Airlines

Friday

Frontier, Southwest, United Airlines

Frontier, Southwest, +1 more

Saturday

Frontier, Southwest, United Airlines

Frontier, Southwest, +1 more

Sunday

Southwest, United Airlines, Frontier

Southwest, United Airlines, +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

Southwest, United Airlines

Wednesday

Frontier, Southwest, United Airlines

Frontier, Southwest, +1 more

Thursday

Southwest, United Airlines

Southwest, United Airlines

Friday

Frontier, Southwest, United Airlines

Frontier, Southwest, +1 more

Saturday

Frontier, Southwest, United Airlines

Frontier, Southwest, +1 more

Sunday

Southwest, United Airlines, Frontier

Southwest, United Airlines, +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.
7.9
SouthwestOverall score based on 4250 reviews
8.0Comfort
8.6Crew
7.5Entertainment
8.1Boarding
7.0Food
Airline reviews

They sent a notice that they were boarding an hour early. We had to leave the club and run to the gate. They said sorry, that came from corporate and was a mistake. They did not have enough seating because the flight before it had not taken off on time. They moved our gate and delayed it for an hour.

2.0 MediocreRobert, Dec 2025
LAS - TPA
Read more Southwest reviews

They sent a notice that they were boarding an hour early. We had to leave the club and run to the gate. They said sorry, that came from corporate and was a mistake. They did not have enough seating because the flight before it had not taken off on time. They moved our gate and delayed it for an hour.

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

The lead steward kept singing about "San Francisco" and hotel California---more annoying than humorous....needs work. Flight was smooth and on time.

Still a fan of open seating. Flight was on schedule and arrived on time. The 737 MAX is very comfortable.

Airline travel is always too cramped to really be pleasant, but the cabin crew on this flight did a pretty good job of making up for it by putting on some music during boarding and sprinkling a few funny remarks into the safety briefing and announcements, and just generally being friendly and helpful. It definitely reminded me of why I prefer the in-flight experience on Southwest!

No delays and arrived to destination 30 min early. Staff was super friendly.

San Diego airport is brand new, spacious, airy and very smooth checkin at SW baggage drop.

Boarded on time but once we were ready for take off, the crew determined that, although every seat was taken, somehow someone was on the wrong flight. Delay, delay delay, announcements and ended up with one person checking EVERY ID against their passenger Manifest only to figure out it was a "clerical error." We departed 54 minutes late causing me to run in the St. Louis Airport to make my connection and lose the priority boarding spot I had paid for. Unnecessary delay.

Flight was delayed due to plane not passing inspection And one of the crew had to time out and we had to wait for another one A 3 hour delay

Connecting flight is on time and boarding was a breeze!

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 😁

Electric plugs didn't work. Entertainment system wasn't working

The design of the light switch on the arm rest is ridiculous.

The gate attendant let me walk right by her with a bag too big for the overhead compartment

Overall, it was a good experience. Boarding was good and there was plenty of overhead bin space for everyone’s carryons (even when we boarded toward the end). Only improvement would be to offer trash service more regularly.

Not clean and was told I would get a great seat and it was not great at all

Flight got delayed for 5 hours no good explanation was offered ;(

Horrible. I would never fly Frontier again. The booking process is tricky at best, but fraudulent in my opinion. Frontier customer service did nothing to rectify my purchase -- I ended up paying more than double what I could have gotten from other airlines and nearly triple what I thought I was buying from Frontier. Their booking practices are unfair to the consumer.

Delayed. Text notifications were slow. Not much information o what was happening. Boarding was slow and confusing. Wasn’t even offered water other flight. Had to ask. No entertainment at all. Felt like.a Greyhound bus.

When I wanted to check in 3 hours prior to boarding time, the employees mentioned “a little over an hour delay” so I waited for an hour then I went to go look for food in the terminal and most people from that flight were in the same area looking for food. Finally I decided after food to check to see if it’s anytime closer and now it’s 2 mins until boarding closes?! What are you kidding me? I didn’t receive anything via sms about boarding now nor via email or on the intercom. I luckily made it through, barely, and then there’s no room for my carry on mind you I’m in the very first row so I had to place my purse in one further row back and my carry on sections down. Not sure who pays for better seats to get your stuff placed all over the plane but that was the worst experience I’ve ever had flying with anyone.

Better than expected. Staff were friendly and nice on both flights.

There was no one at the counter to assist with our check in. The app didn’t work, so I arrived at the airport with time to check in and I couldn’t because no employees were there. When I finally got someone on the phone, it was inside the 60min rule and they said I could no longer check in and they could sell me another ticket. We had to scramble and pay an additional $800 for tickets and THEN AFTER (about 60 min from my original convo with customer service and 10min after original departure time) I had boarded my new flight, there was email saying my original flight from Frontier was delayed and leaving 2hr 50min later, but I STILL wouldn’t have been able to check in. Which means customer service should have been able to see it and let me check in because I was well within my check in time. When I call Frontier, they hang up on me. So their app didn’t work and they employees left and they take zero responsibility or assistance with their “customer service”

Terrible. Flight cancelled with no reasoning and no flights to rebook. Employees were useless and did nothing to help. Did not even know where to retrieve luggage from the cancelled flight. Flyers beware.

No fault of Frontier staff: plane was very late, reached Orlando at 1 am, took a while to get luggage. Weather, gov financial shutdown impact on TSA, air controllers seemed to have multiple flights backed up. Frontier staff seemed to cope as gracefully as possible. It did reassure me that I and my new hip could adapt to travel challenges. Food/entertainment were irrelevant to my trip.

Terrible. The canceled my entire flight when I requested a refund for a trip frontier canceled trip one way.

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.