STL - DEN

$38 Find Cheap Flights from St. Louis to Denver - Compare and Save

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Everything you should know

Cheapest round-trip
$139
Typical prices: $186-$378
Frontier
Sun 12/2Fri 12/7
STL - DEN • Non-stop
Cheapest non-stop
$142
Typical prices: $185-$380
Frontier
Fri 11/9Sun 11/11
STL - DEN • Non-stop
Nonstop flights
You can fly direct with Southwest, United Airlines and Frontier. Average duration is 2h 29m
Direct flights
+1
Direct flights
+1
When to book
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 39% compared to booking last minute.
Insights
Insights
When to travel
Cheapest • 28% price drop
Most popular
Good to know
+1
Good to know
+1
Top layover airports
Cheapest • Avg $235 (round-trip)
Shortest trip • 5h 14m (one-way)
Insights
Insights
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Flight Deals
Booking Insights
Expert advice
Flight Deals

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

 
Discover the best prices for you by selecting your travel dates on KAYAK.

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

Wed, Dec 2 - Mon, Dec 7
Frontier Logo
7:58 pm - 9:29 pmSTL  Lambert-St Louis-DEN Denver Intl
2h 31mnonstop
Frontier Logo
6:41 am - 12:12 amDEN  Denver Intl-STL Lambert-St Louis
16h 31m1 stop Orlando
$139Frontier
Wed, Nov 18 - Tue, Nov 24
Frontier Logo
4:18 pm - 5:48 pmSTL  Lambert-St Louis-DEN Denver Intl
2h 30mnonstop
Frontier Logo
6:42 am - 4:20 pmDEN  Denver Intl-STL Lambert-St Louis
8h 38m1 stop Las Vegas Harry Reid Intl
$140Frontier
Thu, Nov 19 - Tue, Nov 24
Frontier Logo
11:40 am - 1:12 pmSTL  Lambert-St Louis-DEN Denver Intl
2h 32mnonstop
Frontier Logo
6:42 am - 4:20 pmDEN  Denver Intl-STL Lambert-St Louis
8h 38m1 stop Las Vegas Harry Reid Intl
$140Frontier
Sat, Dec 5 - Mon, Dec 7
Southwest Logo
5:25 pm - 6:50 pmSTL  Lambert-St Louis-DEN Denver Intl
2h 25mnonstop
Southwest Logo
6:30 am - 9:35 amDEN  Denver Intl-STL Lambert-St Louis
2h 05mnonstop
$147Southwest
Mon, Dec 7 - Thu, Dec 10
Southwest Logo
8:20 pm - 9:45 pmSTL  Lambert-St Louis-DEN Denver Intl
2h 25mnonstop
Southwest Logo
6:05 pm - 9:10 pmDEN  Denver Intl-STL Lambert-St Louis
2h 05mnonstop
$147Southwest
Wed, Nov 25 - Tue, Dec 1
Southwest Logo
9:50 pm - 11:20 pmSTL  Lambert-St Louis-DEN Denver Intl
2h 30mnonstop
Southwest Logo
6:30 am - 9:35 amDEN  Denver Intl-STL Lambert-St Louis
2h 05mnonstop
$147Southwest
Thu, Jan 7 - Tue, Jan 12
United Airlines Logo
8:52 am - 10:26 amSTL  Lambert-St Louis-DEN Denver Intl
2h 34mnonstop
United Airlines Logo
10:15 am - 1:21 pmDEN  Denver Intl-STL Lambert-St Louis
2h 06mnonstop
$177United Airlines
Thu, Jan 7 - Tue, Jan 12
United Airlines Logo
8:52 am - 10:26 amSTL  Lambert-St Louis-DEN Denver Intl
2h 34mnonstop
United Airlines Logo
3:13 pm - 9:37 pmDEN  Denver Intl-STL Lambert-St Louis
5h 24m1 stop Chicago O'Hare Intl
$187United Airlines
Thu, Dec 17 - Thu, Dec 24
Delta Logo
6:03 am - 10:07 amSTL  Lambert-St Louis-DEN Denver Intl
5h 04m1 stop Minneapolis St Paul
Delta Logo
3:50 pm - 9:41 pmDEN  Denver Intl-STL Lambert-St Louis
4h 51m1 stop Minneapolis St Paul
$187Delta
Fri, Nov 20 - Mon, Nov 23
Delta Logo
6:13 am - 12:20 pmSTL  Lambert-St Louis-DEN Denver Intl
7h 07m1 stop Minneapolis St Paul
Delta Logo
6:30 am - 2:41 pmDEN  Denver Intl-STL Lambert-St Louis
7h 11m1 stop Minneapolis St Paul
$187Delta
Booking Insights

Price, demand and travel trends for St. Louis to Denver flights

Use KAYAK data on prices, travel dates, airlines and seasonal trends to compare options and book flights with more confidence.

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

Round-trip flights from St. Louis to Denver typically range from $186 to $378. The lowest price found in the past 5 days was $139, on Frontier.

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

Based on deals KAYAK users found in the last 12 months, Saturday is the cheapest day of the week to fly from St. Louis to Denver. It’s 16% cheaper than the average day, while Sunday is the most expensive, with prices 19% higher.

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

•February is the cheapest month to fly from St. Louis to Denver at $204 round-trip.
•June ($345) and July ($334) are the most expensive months.
•The price difference between flying in the cheapest and most expensive months is 69% on average.
This is based on KAYAK aggregated and averaged internal data over the past 12 months.

When are flights from St. Louis to Denver the cheapest?

Flights from St. Louis to Denver are cheapest 3 weeks before departure. Booking in this window typically costs about 39% less than the average last-minute fare (within 2 weeks of the flight), based on KAYAK data.

Expert advice

Expert advice for your flight from St. Louis to Denver

 
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.

Key details for St. Louis to Denver flights

Low season

December

Cheapest flight

$38
Beat the crowds with an average 23% drop in travelers.
The most popular month to fly with an average 32% increase in travelers.
One-way flight from St. Louis to Denver

When to book flights from St. Louis to Denver

Are your dates flexible? Find out the best times to travel from St. Louis to Denver based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price

Your St. Louis to Denver flight questions, answered

Find helpful answers about this route, including flight times, airports, airlines and booking tips.

  • What are the earliest and latest flights from St. Louis to Denver?

    These are the earliest and latest flight times available from St. Louis to Denver:

    • Earliest: departs at 5:30 am and lands at 7:59 am
    • Latest: departs at 10:50 pm and lands at 1:19 am.

    The flight takes about 2h 29m.

  • What cabin classes can I book on flights from St. Louis to Denver?

    Two cabin classes are available on flights from St. Louis to Denver:

    • Economy Class
    • First Class

  • How long is a flight from St. Louis to Denver?

    A nonstop flight from St. Louis to Denver takes 2h 29m, covering 767 miles.

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

    No, a passport is not required for this domestic route, but you will need a real ID-compliant driver's license, a state ID or another TSA-accepted form of identification.

  • How much should I expect to pay for a St. Louis to Denver flight?

    Round-trip flights from St. Louis to Denver range from $186 to $378, with an average of $284 over the past 12 months. Anything below $186 counts as a good deal.

  • How expensive are last-minute St. Louis to Denver flights?

    Last-minute fares on this route (booked within two weeks of departure) run 39% above the $284 route average. Book 3 weeks before departure for the lowest fares.

  • How much can I save by taking a layover when flying from St. Louis to Denver?

    On this route, layover flights are cheaper than nonstop options on average. Layover fares average $235 round-trip via Minneapolis St Paul (MSP), compared to $287 for nonstop.

  • What is the standard checked-bag allowance on flights from St. Louis to Denver?

    There is no standard. Checked-bag policies vary by airline on this route. Most carriers charge $40–$100 for the first checked bag in economy. Premium fares and elite-status bookings typically include a free checked bag.

  • Which aircraft model is used most often on flights from St. Louis to Denver?

    The Boeing 737 MAX 8 family is used most often on this route, operated mainly by Southwest. Other aircraft seen on the route include Boeing 737-800 Passenger/BBJ2 (winglets) variants.

  • How are flight departures from St. Louis to Denver spread across the day?

    Morning is the busiest departure period on St. Louis to Denver flights, with 38% of flights leaving in that window. Afternoon departures account for 37%, evening flights for 25%, and night flights for 0%.

  • Which airlines offer Wi-Fi on St. Louis to Denver flights?

    JetBlue is the only airline on the St. Louis to Denver route offering in-flight Wi-Fi. Pricing depends on fare class.

  • How are flight prices from St. Louis to Denver looking right now?

    One-way fares from St. Louis to Denver are currently lower than usual. Average one-way flight prices are about $74, which is 60% below the typical average for this route.

  • What car rental options are available at Denver Intl Airport (DEN)?

    Denver Intl Airport (DEN) hosts 5 major car rental companies, with daily rates starting from around $15 for economy cars. Top options include:

    • Routes Car & Truck Rentals
    • Ace
    • Europcar
    • NU Car
    • Hertz

  • Which airports can I use when flying from St. Louis to Denver?

    Flights from St. Louis to Denver usually depart from Lambert-St Louis (STL) and arrive at Denver Intl (DEN).

  • Which airports do connecting flights from St. Louis to Denver pass through?

    One-stop flights from St. Louis to Denver most commonly connect through:

    • Dallas/Fort Worth (DFW) - 57% of one-stop connections
    • Atlanta Hartsfield-Jackson (ATL) - 13% of one-stop connections
    • Las Vegas Harry Reid Intl (LAS) - 13% of one-stop connections
    • Chicago O'Hare Intl (ORD) - 9% of one-stop connections

  • Can I save money by using flexible dates for flights from St. Louis to Denver?

    Yes. Flexible dates can save you up to 29% on flights from St. Louis to Denver. Saturday is the cheapest departure day at $240 round-trip on average, while Sunday is the most expensive at $338, a difference of $98.

    Cheaper weekend fares like these are typical of routes dominated by weekday business travel.

  • What airlines fly from St. Louis to Denver?

    3 airlines operate flights between St. Louis and Denver. The airlines offering nonstop flights on this route include:

    • Southwest
    • United Airlines
    • Frontier

  • How much time can I save by choosing a different layover airport from St. Louis to Denver?

    Flying via Minneapolis St Paul (MSP) gives the shortest average 1-stop total travel time at 5h 10m, compared with 5h 14m via Chicago O'Hare Intl (ORD) and 6h 50m via Dallas/Fort Worth (DFW).

  • What is the time difference between St. Louis and Denver?

    Denver is 1 hour behind St. Louis (Mountain Time vs Central Time). Plan for the time shift when scheduling connections or first-day activities.

  • What popular places can I visit in Denver?

    Some of the most popular sights in Denver are Colorado Convention Center, Coors Field and Ball Arena. These are among the most viewed places in Denver on KAYAK.

  • Which airlines offer extra legroom and free seat selection on St. Louis to Denver flights?

    Among airlines operating St. Louis to Denver flights:

    • United Airlines: offers extra legroom; offers free seat selection
    • Southwest: offers free seat selection
    • Frontier: offers free seat selection

    Extra legroom and free seat selection availability depends on fare class and route.

  • Which airlines include bags at no extra cost on St. Louis to Denver flights?

    Here are some options for this route, based on selected ticket types and cabin classes:

    • United Airlines: a cabin bag and a checked bag in Economy Class
    • Southwest: a cabin bag and a checked bag in Economy Class
    • Frontier: a cabin bag in Economy Class class

    Bag allowance can vary by ticket type, cabin class, route and airline, so always check the fare details before booking.

  • How can I fly from STL to DEN?

    Frontier and United operate several nonstop flights from STL to DEN that depart throughout the day. American and United operate several flights per day that have one stop. The layover for these flights is often in cities such as Chicago (ORD), Charlotte (CLT), and Dallas (DFW).

  • Does STL have a USO lounge?

    STL provides a USO lounge for active military service members and their families. The James S. McDonnell USO, located in Terminal 1 on the lower level opposite M6 baggage claim, is open 24h a day, 7 days a week, 365 days a year. All services and amenities at the USO are without charge. Some of these offerings include beverages, snacks, Wi-Fi, a DSN phone, laptops, and computers. You can also relax by watching cable TV, watching a DVD or a Blu-ray disc, or playing Xbox 360. The USO also has a seating area, a quiet area where you can sleep, a nursery, and toiletries.

  • Does STL have designated lactation areas for nursing mothers who might prefer some privacy?

    STL provides dedicated private spaces to mothers who want to nurse or breast pump in clean privacy. These lactation suites are located past security at Gates A10, C9, and E33. Each calm, clean room has power outlets for a breast pump, a sink, and a full back comfortable chair with a movable arm table. There is also an Ottoman and a bench so that additional people, such as baby’s siblings, can join mama in the space, with enough room for luggage.

  • How do I get into downtown Denver from the DEN airport?

    You can take the A Line of the RTD bus that runs to the center of Denver. Also, you can take a train that departs from DEN 4 to 6 times an hour. Public transportation from DEN is very convenient to get you into downtown Denver.

Your guide to booking St. Louis to Denver flights

Get tips on when to book, when to fly and what to know before your trip.
  • If your dates are flexible, aim for a Saturday departure and avoid flying on Sunday. On this route, Saturday flights average $240, about $98 less than Sunday fares (29% savings) based on the last 12 months.
  • For the best chance at a low fare, aim to book around 3 weeks before you fly. On this route, that window historically saves about 39% versus last-minute pricing (KAYAK booking data, last 12 months).
  • If you can choose when to travel, plan your St. Louis to Denver trip for February. Fares historically average $204 round-trip in that month - typically $141 less than the most expensive month, which is June (based on the last 12 months).
  • If you have the time, taking a 1-stop flight through Minneapolis St Paul Airport (MSP) can be cheaper than flying direct. The cheapest layover option averages $235 round-trip on this route - about $51 less than direct flights (based on the last 12 months).
  • If you're arriving late at night and need somewhere to stay, check out these hotels close to Denver Intl Airport.

    • The Westin Denver International Airport
  • When you arrive at the Denver International Airport (DEN), you can ease the stiffness out of your muscles by getting a massage at the spa, The Massage, at the B concourse on the mezzanine level. Or you could try the Colorado Oasis or Xpres spas at DEN.
  • If when you arrive at DEN you need to pick up some necessities you couldn’t pack due to airline restrictions, stop at the Peak News and Gifts to get the toiletries and essentials you need before heading into Denver.
  • As part of the Lambert Art and Culture Program at the Lambert St. Louis International Airport (STL), the airport has installed a piano permanently in Terminal 1, so travelers are treated to live music as they make their way to their plane.
  • DEN is happy to provide service animals and pets with relief areas in all three terminals, in the middle of all the gates. For A, B, and C terminals, the pet relief areas are near the US mail drop areas. If you are in Jeppesen terminal, the pet relief area is on the northwest side of the second level.
  • If you want to park your car at STL before you head off to Denver, long-term parking lots are available in lots B and D for an affordable price, and payment is usually due at the time you exit the lot. Free shuttles that run every 10min can take you to your terminal.

Prefer to fly direct from St. Louis to Denver?

 
Find which airlines fly direct from Lambert-St Louis Airport to Denver Intl Airport, which days they fly and book direct flights.

Direct departures

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

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

Southwest,United Airlines

Southwest,United Airlines

See more direct flights

Direct returns

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

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

Southwest,United Airlines

Southwest,United Airlines

See more direct flights

More options for your flight from St. Louis to Denver

Complete your trip to Denver with a hotel stay or car rental