DEN - STL

$102 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 8/31. 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
$161
Typical prices: $287-$131
Frontier
Thu 8/20Sun 8/23
DEN - STL • Non-stop
Cheapest one-way
$102
Typical prices: $109-$215
Frontier
Mon 8/31
DEN - STL • 1 stop
Advice from real travelers
AI-powered summary based on content written by travel experts. AI can make mistakes.
Southwest free carry-on adds value, though checked bags now cost extra.
Frontier avoids check-in fees via app; United Economy Plus adds legroom.
Expert advice
Expert advice
Expert advice
Expert advice
Top airlines
Cheapest • from $161 (round-trip)
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Nonstop flights
You can fly direct with Frontier, Southwest and United Airlines. Average duration is 2h 08m
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 3 weeks in advance save around 32% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 35% 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

Thu, Aug 20 - Sun, Aug 23
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
$161Frontier
Mon, Aug 17 - Wed, Sep 2
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
Frontier Logo
4:10 pm - 10:54 pm
STL
-
DEN
7h 44m
1 stop
$163Frontier
Sat, Jun 27 - Tue, Jun 30
Frontier Logo
3:41 pm - 6:53 pm
DEN
-
STL
2h 12mnonstop
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
$166Frontier
Wed, Aug 26 - Sun, Aug 30
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
Frontier Logo
6:33 pm - 8:58 am
STL
-
DEN
15h 25m
1 stop
$167Frontier
Sat, Jun 27 - Tue, Jun 30
Frontier Logo
3:41 pm - 6:53 pm
DEN
-
STL
2h 12mnonstop
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
$168Frontier
Wed, Jun 24 - Tue, Jun 30
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
$170Frontier
Thu, Aug 6 - Mon, Aug 10
Frontier Logo
5:05 am - 2:56 pm
DEN
-
STL
8h 51m
1 stop
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
$171Frontier
Tue, Aug 11 - Sun, Aug 16
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
Frontier Logo
6:34 pm - 9:03 am
STL
-
DEN
15h 29m
1 stop
$172Frontier
Thu, Aug 6 - Sun, Aug 9
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
$173Frontier
Sun, Aug 9 - Sat, Aug 15
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
$174Frontier
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.

How much is a round-trip flight from Denver to St. Louis?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Denver to St. Louis departing in August.

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 March and April, where the average cost of round-trip tickets is $312 and $304 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 32% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 16 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$102
Best time to beat the crowds with an average 35% drop in price.
Most popular time to fly with an average 14% 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 5 days, the lowest price for a flight from Denver to St. Louis was $102 for a one-way ticket and $161 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, American Airlines, and Delta 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 $336 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 $330 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 $149 or less one-way and $255 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

Frontier,Southwest,United Airlines

Frontier,Southwest, +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

Frontier,Southwest,United Airlines

Frontier,Southwest, +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 4256 reviews
7.0Food
8.1Boarding
8.6Crew
8.0Comfort
7.5Entertainment
Airline reviews

Flight coming out of Buffalo was delayed, so we had to be rescheduled on another flight from Baltimore to Phoenix which means we had a long layover and got home 3.5 hours late. Shuttle to parking stopped at 10pm, so we had to pay for an Uber to the parking lot and got charged an extra day of parking since it was after midnight. Not the best experience. Long day!

2.0 MediocreDawn, Jun 2026
BUF - BWI
Read more Southwest reviews

Flight coming out of Buffalo was delayed, so we had to be rescheduled on another flight from Baltimore to Phoenix which means we had a long layover and got home 3.5 hours late. Shuttle to parking stopped at 10pm, so we had to pay for an Uber to the parking lot and got charged an extra day of parking since it was after midnight. Not the best experience. Long day!

Was fine, delayed and feels like southwest is always late

I don't know why flying out of Sarasota requires two plane changes.

The first time I flew in the extra legroom section. It was difficult to notice a difference. I had bad luck with my neighbors. The crew was okay. Southwest has reduced the live TV options.

The flight was smooth. The Southwest experience has degraded overall, but this one was okay.

No gluten free snacks. Seats felt worn or bare bones even though it was a new 737 MAX 8.

One major problem that was very unprofessional and uncalled for. Plane landed and we had to wait 20 minutes to get off the plane since they were waiting for someone to come to the gate to drive the jetway. Southwest couldn't have someone available and waiting for the plane to land? Is there only one person in Hobby airport who knows to drive the jetway? Was he at lunch? In the bar? Uncomfortable and uncalled for!

The checking experience in Orlando was terrible, almost missed the flight. Too many travelers and Southwest completely understaffed.

I'm glad it wasn't only 75% full because I could get a good seat

if I was good. Not happy that I have to pay extra money to get the seat I need for lake room, but I guess that’s a sign of the times.

New plane was lovely. Crew customer service is always lax but expected. Kraft on time and arrived safely.

It was a short flight so I was expecting too much

Had a one hour delay due to mechanical issue. I didn’t think I’d be able to make my connecting flight, but they waited for me and greeted me when I arrived to help things run smooth.

O’hsre taxi and deboarding took 40 minutes. Needed 20 minutes extra time between connecting flights to avoid running through terminal.

Was great in general, try to respect time and excuses when slight changes have been made, appreciated!

Really hard landing... as in slammed into the runway then hit the brakes really hard ...

Every staff member was professional, friendly and courteous. The pizza twist was ok. It was warm but too much dough.

Wonderful in-seat entertainment with seatback screens and huge selection of quality movies. The ability to bluetooth connect headphones was amazing.

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

There weren't enough employees at check in took awhile to get bags checked. There wasn't a wheel chair for me, I was sent to someone who turns out to work for a different airline, if My flight hadn't been delayed I probably would have missed my flight as it was, by the time I arrived at my gate, they started boarding in about 15 minutes. I don't know who took me to my gate, definitely was not the normal people who take passengers to the gate. I'm guessing she may have been in a management position. I wish I knew her name, she went beyond to help me. With that said everyone was kind, and were doing the best they could. So, I choose to say it was an Adventure, stressful start, but good. In the end went well. The situation was not only difficult for passengers but the employee's.

The staff at the check in counter was so rude. Made you feel Incompetent

Frontier scheduled a 40 minute connection in DEN. What they failed to mention was that they “close the doors” 20 mins prior to departure, which means you only have 20 mins. Not enough time. Possibly against DOT regulations. Filing complaint.

Flight was scheduled at 9:40pm. Got delayed to 10 am, the next day. crazy

The bag check, flight check-in, and onboard experience convinced my wife and me that we will actively go out of our way to avoid flying Frontier Airlines in the future. At bag check, we were informed that check-in could only be completed via the Frontier mobile app. Unfortunately, the app was extremely frustrating—sending us through repetitive, confusing loops that repeatedly forced us to decline add-on services with nearly every click. While most airline apps upsell, this one felt intentionally exhausting. As the process dragged on, we became genuinely concerned that my phone battery would die before check-in could be completed. We approached the bag check staff—who were standing together talking—and explained both our frustration and our predicament. They laughed. Later, my wife described the interaction as “gaslighting,” which felt accurate. We were then informed it would cost $25 per person simply to have our boarding passes printed. From that point forward, the tone of the experience was consistently hostile. The bag check employees were condescending and combative, behaving more like bullies than customer service staff. Unfortunately, that same attitude continued onboard. One flight attendant argued with me when I attempted to stow my backpack in the overhead bin. I explained that we had each paid $75 to check our bags specifically so we would not need to use carry-on space and could have adequate legroom. She demanded to see my ticket, pointed out that it said “no carry-on”—which I acknowledged—and I reiterated that this was precisely why we paid to check our bags. Her response was, “I don’t make the rules.” She then walked away, but not before asking if I “truly wanted to fly back to Chicago today?”—an unnecessary and unmistakable threat. It is also worth noting that despite booking our tickets together in the same transaction, we were not seated together. Upon our return to Chicago—where we could once again sit together—we compared onboard experiences. We both remarked on how unhappy the flight attendants appeared and how each of us was separately asked whether we would like to purchase a beverage. We declined. At no point was water mentioned as an option, leaving us with the clear impression that even water came at a cost—or that complimentary water, if available at all, was deliberately left unmentioned. Overall, the experience was shocking and deeply disappointing, but it was also a profound learning experience—one we will not forget and will not repeat. -Steve

Plane was hot and miserable and the crew was rude!

12 hour delay required getting on and off plane 3 times - would have at least liked to have been offered a snack or drink

They didn’t offer a water, even after I asked

They switched our terminal 3 times and we were delayed for four plus hours!!!

It was an early flight and most people napped/slept and the crew let us which was nice.

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.

Compare transportation modes for Denver to St. Louis

Transportation modeAverage priceAverage duration
Flights$5672h 05m
Buses$16617h 05m