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Flights from St. Louis to Denver

Book direct flights from St. Louis to Denver: One way flights from $36, round trip flights from $151. Find flight deals for the next 3 months below.

      • Cheapest nonstop
        STL 8:08 PM
        2h 33m
        Nonstop
        DEN 9:41 PM
        St. Louis - Denver | Thu, Jun 4 | Frontier Airlines
        DEN 4:15 PM
        2h 8m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Sat, Jun 6 | Frontier Airlines
        $151 $318
        53% off
        53% off
        $318 $151
      • STL 8:08 PM
        2h 33m
        Nonstop
        DEN 9:41 PM
        St. Louis - Denver | Sun, May 24 | Frontier Airlines
        DEN 4:15 PM
        2h 8m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Thu, May 28 | Frontier Airlines
        $160 $318
        50% off
        50% off
        $318 $160
      • STL 8:08 PM
        2h 33m
        Nonstop
        DEN 9:41 PM
        St. Louis - Denver | Sat, May 23 | Frontier Airlines
        DEN 4:15 PM
        2h 8m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Mon, May 25 | Frontier Airlines
        $210 $318
        34% off
        34% off
        $318 $210
      • STL 8:08 PM
        2h 36m
        Nonstop
        DEN 9:44 PM
        St. Louis - Denver | Thu, Jul 9 | Frontier Airlines
        DEN 4:10 PM
        2h 13m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Sun, Jul 12 | Frontier Airlines
        $223
        30% off
        $318 $223
      • STL 8:08 PM
        2h 33m
        Nonstop
        DEN 9:41 PM
        St. Louis - Denver | Fri, May 22 | Frontier Airlines
        DEN 4:15 PM
        2h 8m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Mon, May 25 | Frontier Airlines
        $249
        22% off
        $318 $249
      • STL 5:10 AM
        2h 22m
        Nonstop
        DEN 6:32 AM
        St. Louis - Denver | Thu, Jun 4 | United Airlines
        DEN 4:15 PM
        2h 8m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Sat, Jun 6 | Frontier Airlines
        $258
        19% off
        $318 $258
      • STL 2:56 PM
        7h 46m
        1 stop
        DEN 9:42 PM
        St. Louis - Denver | Fri, Jun 19 | Frontier Airlines
        DEN 10:09 AM
        7h 9m
        1 stop
        STL 6:18 PM
        Denver - St. Louis | Tue, Jun 23 | Frontier Airlines
        $211
        34% off
        $318 $211
      • STL 5:15 PM
        8h 18m
        1 stop
        DEN 12:33 AM
        St. Louis - Denver | Sat, May 23 | Delta Air Lines
        DEN 4:15 PM
        2h 8m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Mon, May 25 | Frontier Airlines
        $249
        22% off
        $318 $249
      • STL 9:06 PM
        7h 19m
        1 stop
        DEN 3:25 AM
        St. Louis - Denver | Thu, May 21 | Frontier Airlines
        DEN 4:15 PM
        2h 8m
        Nonstop
        STL 7:23 PM
        Denver - St. Louis | Mon, May 25 | Frontier Airlines
        $260
        18% off
        $318 $260
      • STL 1:00 PM
        17h 25m
        1 stop
        DEN 2:00 PM
        St. Louis - Denver | Mon, May 18 | Normal Airline
        DEN 3:00 PM
        6h
        Nonstop
        STL 4:00 PM
        Denver - St. Louis | Wed, May 20 | Normal Airline
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      • Cheapest nonstop
        STL 8:08 PM
        2h 33m
        Nonstop
        DEN 9:41 PM
        St. Louis - Denver | Tue, May 26 | Frontier Airlines
        $36 $136
        74% off
        74% off
        $136 $36
      • STL 8:08 PM
        2h 36m
        Nonstop
        DEN 9:44 PM
        St. Louis - Denver | Fri, Jun 12 | Frontier Airlines
        $74 $136
        46% off
        46% off
        $136 $74
      • STL 8:08 PM
        2h 36m
        Nonstop
        DEN 9:44 PM
        St. Louis - Denver | Sun, Jun 14 | Frontier Airlines
        $79 $136
        42% off
        42% off
        $136 $79
      • STL 8:08 PM
        2h 33m
        Nonstop
        DEN 9:41 PM
        St. Louis - Denver | Sun, Jun 7 | Frontier Airlines
        $89
        35% off
        $136 $89
      • STL 8:08 PM
        2h 33m
        Nonstop
        DEN 9:41 PM
        St. Louis - Denver | Wed, May 27 | Frontier Airlines
        $99
        27% off
        $136 $99
      • STL 4:48 PM
        2h 35m
        Nonstop
        DEN 6:23 PM
        St. Louis - Denver | Tue, May 26 | United Airlines
        $101
        26% off
        $136 $101
      • STL 4:48 PM
        2h 35m
        Nonstop
        DEN 6:23 PM
        St. Louis - Denver | Thu, May 28 | United Airlines
        $111
        18% off
        $136 $111
      • STL 9:21 PM
        7h 4m
        1 stop
        DEN 3:25 AM
        St. Louis - Denver | Thu, May 28 | Frontier Airlines
        $90
        34% off
        $136 $90
      • STL 7:03 PM
        6h 35m
        1 stop
        DEN 12:38 AM
        St. Louis - Denver | Wed, Jun 10 | Frontier Airlines
        $95
        30% off
        $136 $95
      • STL 5:36 PM
        7h 5m
        1 stop
        DEN 11:41 PM
        St. Louis - Denver | Tue, May 26 | Delta Air Lines
        $107
        21% off
        $136 $107
      • STL 1:00 PM
        17h 25m
        1 stop
        DEN 2:00 PM
        St. Louis - Denver | Mon, May 18 | Normal Airline
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Displayed flight fares from St. Louis to Denver are based on average prices across airlines for the next 3 months, according to the latest Trip.com database.

Trip.com price insights on flights from St. Louis to Denver

Which month has the cheapest one-way flights from to Denver?

The average price of one-way flights from to Denver purchased by Trip.com users by month over the past 12 months.

Based on Trip.com’s data, the cheapest month for flights from to Denver is October, with an average price of $65; while the month with the highest flight price is usually November, with an average price of up to $271.

$271
$168
$65
0
    Cheapest
  • $107
    May
  • $87
    Jun
  • $120
    Jul
  • $168
    Aug
  • $103
    Sep
  • $65
    Oct
  • $271
    Nov
  • $159
    Dec
  • $155
    Jan
  • $219
    Feb
  • $83
    Mar
  • $112
    Apr

When is the cheapest day to fly from St. Louis to Denver during Memorial Day?

Data is based on the lowest one-way price from St. Louis to Denver during Memorial Day on Trip.com in the past 3 days.

Memorial Day is scheduled for May 25. The cheapest flights from St. Louis to Denver are available on May 25, with fares starting at $127.

$237
$182
$127
$72
    Cheapest
  • $155
    22
    May
  • $237
    23
  • $155
    24
  • $127
    25
  • $236
    26
  • $139
    27

Frequently Asked Questions

  • What are the cheapest flights from St. Louis to Denver (STL-DEN)?

    Based on Trip.com data, Frontier Airlines offers one-way fares as low as $36 on Cheapest nonstop routes (e.g. STL to DEN on Tue, May 26), while Frontier Airlines offers Cheapest nonstop round-trips from $151 departing on Thu, Jun 4 and returning on Sat, Jun 6.
  • At the moment, you can catch a nonstop flight from St. Louis to Denver with the following airlines, including: Frontier Airlines United Airlines Selected airlines are based on historical data collected from flight bookings users made on Trip.com within the last 90 days.
  • It takes around 2 hours 32 minutes to fly from St. Louis (STL) to Denver (DEN).
  • By analyzing data from all airlines on the Trip.com flight calendar, it looks like the best time to book a flight from St. Louis to Denver is around 40 days (6 weeks) in advance, and the best time to fly is usually on Tuesday, Wednesday, and Saturday. Tuesday typically offers the cheapest flights for departure, while Saturday offers the best return deals.
  • Based on Trip.com data in the past 4 weeks, there is 12 flight per week flying from St. Louis to Denver. You can check the weekly schedule for popular airlines on this route below: Frontier Airlines: S/-/-/W/T/F/S -- F94567 (20:06) United Airlines: S/M/T/-/-/F/S -- UA1302 (09:03)
  • To find best deals on flights from St. Louis to Denver, you can use various tools on Trip.com:
    · Be flexible with your travel dates to get the cheapest flight deal. Now the cheapest flight deal is on Tue, May 26, with one-way flights priced at just $36.
    · Compare airlines strategically. Budget carriers often provide the lowest base fares, while we found the most affordable airline currently operating on this route is Frontier Airlines.
    · Set up price alerts to easily monitor ticket prices without having to check every day.
    · Check Trip.com flight deals and promo codes frequently.
    · Avoid peak season unless you book very early. It seems the peak season for Denver travel is around January.
    · Get exclusive promo codes for Trip.com app users.
  • The cheapest months to fly from St. Louis to Denver is October, when demand for travel is lower.
  • After crunching the numbers on our May flight calendar, it's currently cheapest to fly from St. Louis to Denver on May 27, 2026 with Frontier Airlines, with prices starting at $80.
  • You can land at any one of the following hubs in Denver, with St. Louis Lambert International Airport to Denver International Airport (STL-DEN) is by far the most common option on this route: Denver International Airport (DEN) Rocky Mountain Metropolitan Airport (BJC).
  • The time difference between Denver and St. Louis is 1h.
  • Tickets can only be changed or canceled if permitted by airline policy. To submit a change or cancellation request, go to the flight bookings page, select the option to change or cancel your booking, choose the relevant passengers and segment, and submit a request. Please note that additional charges may apply according to the airline ticket policy. However, if the flight has been rescheduled and you would like to change or cancel your ticket, you can submit an involuntary cancellation request. For more details about change and cancellation policies, please check the customer support pages.

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Note: Prices shown on this page are estimated lowest price and include all taxes and fees found in the last 24 hours.

Book with no extra fees

Prices displayed in this page are all-inclusive prices (incl. taxes, fuel surcharge, civil aviation development fund, etc) with all fees confirmed before payment. Fees for luggage, meals, WLAN, or other additional services are also included as shown in the flight cards.

Real-time pricing updates

Prices, availability, and travel information on this page were updated within last 24 hours—even in real-time. The more popular the route, the more precise the data.

Change & Cancellation Policy

Trip.com displays flight cancellation and change policies for each flight ticket during the booking process, including fees and applicable conditions. Please check the following scenarios:
Voluntary cancellation/change:
To submit a change or cancellation request, go to the flight bookings page, select the option to change or cancel your booking, choose the relevant passengers and segment, and submit a request. Please note that additional charges may apply according to the airline ticket policy.
Cancellation/change due to a flight schedule change:
If the flight has been rescheduled and you would like to change or cancel your ticket, you can submit an involuntary cancellation request. For more details about change and cancellation policies, please check the customer support pages.