$44+ Cheap flights from St. Louis to Denver (STL - DEN)
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/14. Fares are subject to change and may not be available on all flights or dates of travel.
STL — DEN
Oct 24 — Oct 311
Round-trip
1 adult, Economy
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Find cheap flights from St. Louis to Denver with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from Lambert-St Louis to Denver Intl are usually found in January or November, booked 18 days in advance, depart on a Saturday or Wednesday and return on a Saturday
Cheap flight deals from St. Louis to Denver
Cheapest
Best
Last-minute
One-way
Cheapest flights from St. Louis to DenverExplore the most affordable flight options available from St. Louis to Denver. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 24, 2026.
Explore the most affordable flight options available from St. Louis to Denver. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 24, 2026.
This CheapOair deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/214:19 pm -
Nonstop2h 33m
Sat 10/246:40 am -
1 stop15h 33m
Deal found 9/22![Frontier logo]()
$141
This Kiwi.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/198:00 pm -
Nonstop2h 39m
Wed 10/216:10 am -
2 stops10h 30m
Deal found 9/22![Frontier logo]()
$142
This Kiwi.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/54:26 pm -
1 stop16h 47m
Sat 11/74:09 pm -
Nonstop2h 05m
Deal found 9/22![Frontier logo]()
$143
This Kiwi.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/54:26 pm -
1 stop16h 47m
Mon 11/94:09 pm -
Nonstop2h 05m
Deal found 9/22![Frontier logo]()
$144
This Cheapflightsfares deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/212:02 pm -
1 stop8h 55m
Mon 12/76:41 am -
1 stop16h 31m
Deal found 9/23![Frontier logo]()
$145
This Cheapflightsfares deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/268:00 pm -
Nonstop2h 39m
Mon 11/24:09 pm -
Nonstop2h 05m
Deal found 9/21![Frontier logo]()
$146
This Kiwi.com deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/177:42 pm -
Nonstop2h 27m
Tue 10/209:12 pm -
2 stops19h 28m
Deal found 9/21![Frontier logo]()
$147
This Cheapflightsfares deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/238:00 pm -
Nonstop2h 39m
Mon 10/266:35 am -
1 stop9h 23m
Deal found 9/20![Frontier logo]()
$148
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/168:00 pm -
Nonstop2h 39m
Mon 10/194:12 pm -
Nonstop2h 03m
Deal found 9/19![Frontier logo]()
$150
This Kiwi.com deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/216:35 pm -
2 stops18h 22m
Wed 10/2812:21 pm -
Nonstop2h 02m
Deal found 9/23![Frontier logo]()
$151
This CheapOair deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/307:59 pm -
Nonstop2h 31m
Mon 11/210:41 am -
1 stop5h 59m
Deal found 9/22![Frontier logo]()
$152
This Kiwi.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/107:42 pm -
Nonstop2h 27m
Wed 10/146:10 am -
2 stops10h 30m
Deal found 9/19![Frontier logo]()
$153
Best flights from St. Louis to DenverDiscover carefully curated flight deals from St. Louis to Denver that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 24, 2026.
Discover carefully curated flight deals from St. Louis to Denver that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 24, 2026.
This Southwest deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/162:35 pm -
Nonstop2h 25m
Thu 11/196:30 am -
Nonstop2h 05m
Deal found 9/22![Southwest logo]()
$177
This Delta deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/247:05 am -
1 stop8h 50m
Tue 12/295:01 am -
1 stop7h 19m
Deal found 9/23![Delta logo]()
$231
This United Airlines deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/261:40 pm -
Nonstop2h 29m
Sat 10/319:35 am -
Nonstop2h 03m
Deal found 9/23![United Airlines logo]()
$277
This Southwest deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/286:10 pm -
Nonstop2h 20m
Sun 11/14:20 pm -
Nonstop1h 55m
Deal found 9/21![Southwest logo]()
$297
This United Airlines deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/231:36 pm -
Nonstop2h 24m
Tue 10/271:55 pm -
Nonstop2h 02m
Deal found 9/21![United Airlines logo]()
$304
This Southwest deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/89:50 pm -
Nonstop2h 25m
Mon 10/125:50 am -
Nonstop2h 00m
Deal found 9/19![Southwest logo]()
$298
This United Airlines deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/155:10 am -
Nonstop2h 33m
Tue 10/205:30 pm -
Nonstop2h 06m
Deal found 9/22![United Airlines logo]()
$351
This Southwest deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/169:50 pm -
Nonstop2h 25m
Sun 10/186:20 am -
Nonstop2h 00m
Deal found 9/21![Southwest logo]()
$324
This United Airlines deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/71:36 pm -
Nonstop2h 24m
Mon 10/128:28 pm -
Nonstop2h 16m
Deal found 9/23![United Airlines logo]()
$353
This United Airlines deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/94:39 pm -
Nonstop2h 31m
Tue 10/138:28 pm -
Nonstop2h 16m
Deal found 9/23![United Airlines logo]()
$372
This United Airlines deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/125:10 am -
Nonstop2h 33m
Sun 10/188:28 pm -
Nonstop2h 16m
Deal found 9/19![United Airlines logo]()
$471
Last-minute flights from St. Louis to DenverDiscover last-minute flight deals from St. Louis to Denver. Data last updated September 24, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Denver. Data last updated September 24, 2026 and is based on user searches.
This deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/268:10 pm -
Nonstop2h 29m
Wed 9/304:12 pm -
Nonstop2h 05m
Deal found 9/23![Frontier logo]()
$145
This Kiwi.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/107:42 pm -
Nonstop2h 27m
Wed 10/146:10 am -
2 stops10h 30m
Deal found 9/19![Frontier logo]()
$153
This Kiwi.com deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/146:35 pm -
2 stops18h 22m
Sat 10/173:54 pm -
Nonstop2h 03m
Deal found 9/21![Frontier logo]()
$155
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/168:00 pm -
Nonstop2h 39m
Mon 10/194:12 pm -
Nonstop2h 03m
Deal found 9/19![Frontier logo]()
$150
This Kiwi.com deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/177:42 pm -
Nonstop2h 27m
Tue 10/209:12 pm -
2 stops19h 28m
Deal found 9/21![Frontier logo]()
$147
This Kiwi.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/198:00 pm -
Nonstop2h 39m
Wed 10/216:10 am -
2 stops10h 30m
Deal found 9/22![Frontier logo]()
$142
This CheapOair deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/214:19 pm -
Nonstop2h 33m
Sat 10/246:40 am -
1 stop15h 33m
Deal found 9/22![Frontier logo]()
$141
This Kiwi.com deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/216:35 pm -
2 stops18h 22m
Wed 10/2812:21 pm -
Nonstop2h 02m
Deal found 9/23![Frontier logo]()
$151
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/238:00 pm -
Nonstop2h 39m
Mon 10/266:35 am -
1 stop9h 23m
Deal found 9/19![Frontier logo]()
$148
This Kiwi.com deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/238:00 pm -
Nonstop2h 39m
Tue 10/276:31 pm -
1 stop22h 09m
Deal found 9/20![Frontier logo]()
$154
This Cheapflightsfares deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/268:00 pm -
Nonstop2h 39m
Mon 11/24:09 pm -
Nonstop2h 05m
Deal found 9/21![Frontier logo]()
$146
This CheapOair deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/307:59 pm -
Nonstop2h 31m
Mon 11/210:41 am -
1 stop5h 59m
Deal found 9/22![Frontier logo]()
$152
One-way flights from St. Louis to DenverSearch for one-way flight options from St. Louis to Denver. Find affordable one-way fares based on user searches. Data last updated September 24, 2026.
Search for one-way flight options from St. Louis to Denver. Find affordable one-way fares based on user searches. Data last updated September 24, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/144:19 pm -
Nonstop2h 33m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![Frontier logo]()
$44
This Expedia deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/284:18 pm -
Nonstop2h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Frontier logo]()
$54
This Super.com deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/78:10 pm -
Nonstop2h 29m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![Frontier logo]()
$69
This Super.com deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/238:00 pm -
Nonstop2h 39m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$70
This Super.com deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/58:10 pm -
Nonstop2h 29m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![Frontier logo]()
$73
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/215:15 pm -
1 stop8h 39m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/19![Frontier logo]()
$79
This Super.com deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/198:00 pm -
Nonstop2h 39m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/20![Frontier logo]()
$80
This Frontier deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/217:49 pm -
Nonstop2h 31m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/20![Frontier logo]()
$81
This Super.com deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/261:30 pm -
1 stop24h 12m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![Frontier logo]()
$83
This Super.com deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/314:26 pm -
1 stop17h 47m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$84
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/54:26 pm -
1 stop24h 09m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/19![Frontier logo]()
$85
Find flight deals from St. Louis to Denver
Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Denver (DEN). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated September 24, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $141 (CheapOair) |
One-way from | $44 (Cheapflightsfares) |
Popular in | June |
Cheapest in | January |
Average price | $275 |
Good round-trip deal | $309 or less |
Good one-way deal | $179 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from St. Louis to Denver that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 7,457,451 searches. Data last updated September 24, 2026.
Use the filters below to find and compare flights from St. Louis to Denver that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Mon 10/12
9:50 pm-11:15 pm
Nonstop2h 25m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$89
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Tue 12/22
6:09 pm-7:45 pm
Nonstop2h 36m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$89
Quickest round-trip
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Tue 10/27
6:10 pm-7:30 pm
Nonstop2h 20m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$89
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Wed 12/23
6:09 pm-7:45 pm
Nonstop2h 36m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$89
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Thu 10/22
9:50 pm-11:15 pm
Nonstop2h 25m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$89
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Tue 10/27
7:00 am-11:50 am
1 stop5h 50m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$99
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Thu 12/17
5:31 pm-11:22 pm
1 stop6h 51m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$99
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Tue 10/20
12:00 pm-5:52 pm
1 stop6h 52m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$99
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Wed 10/14
8:30 am-1:10 pm
1 stop5h 40m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$99
St. LouisDenver
STL Lambert-St Louis - DEN Denver Intl
STLDEN
Lambert-St Louis
Sat 11/21
8:05 am-9:30 am
Nonstop2h 25m
Denver Intl
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$163
Showing 1-10 of 21 resultsSorted by cheapest first
Compare providers for flights from St. Louis to Denver
Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Denver in September.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*1 star | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*1 star | |
| Price Accuracy1 star | Trust Score*3 stars |
- Most accurate provider: When it comes to deals on St. Louis-Denver flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Denver flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Denver flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on St. Louis-Denver flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Denver flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.
Best time to book a flight from St. Louis to Denver
Have a flexible travel schedule? Discover the best time to fly to Denver from St. Louis with our price prediction graph.
STL-DEN
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from St. Louis to Denver
How far ahead should I book a flight from St. Louis to Denver?
Booking 17 days in advance of your planned departure date is, on average, the best time to get cheap flights from St. Louis to Denver. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
What is the cheapest month to book a flight from St. Louis to Denver?
Currently, January is the cheapest month in which you can book a flight from St. Louis to Denver (average of $207). Flying from St. Louis to Denver in June is currently the most expensive (average of $346). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from STL to DEN?
Find hourly flight availability from St. Louis to Denver. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 24, 2026.
It’s optimal to fly from St. Louis to Denver in the evening. By choosing this option you can save up to 48% on the cost of your flight, compared to a flight in the morning.
What is the cheapest day to fly from St. Louis to Denver?
Use this chart to determine the cheapest time to fly round-trip from St. Louis to Denver. Price data was last updated on September 19, 2026.
Travelers seeking maximum savings on their St. Louis to Denver flight should consider departing on Tuesday evenings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
The best insider tips for St. Louis to Denver flights
AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Denver trip
Our travel experts
Reviews of airlines servicing Denver
Get insights into the airlines that provide service to Denver. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Denver. Reviews last updated September 24, 2026.
Get a feel of what it's like to fly with Southwest,United Airlines, andFrontier from St. Louis to Denver by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Boarding
8.1
Comfort
8.0
Crew
8.6
Food
7.0
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Comfort
8.0
Crew
8.6
Food
7.0
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Comfort
8.0
Crew
8.6
Food
7.0
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Comfort
8.0
Crew
8.6
Food
7.0
Entertainment
7.5
Overall
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Related info for your journey
Find useful and relevant information for your journey from St. Louis to Denver. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near Denver?
Book flights to Denver if you plan to visit one of these locationsThornton
Westminster
Lakewood
Centennial
Black Hawk
Broomfield
Golden
Wheat Ridge
Silverthorne
Central City
Fort Morgan
Greeley
Cripple Creek
Frisco
Winter Park
Limon
Englewood
Manitou Springs
Glendale
Evergreen
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Other flights to Denver
Explore flights to Denver departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on September 24, 2026.
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St. Louis and Denver flights
Browse other St. Louis and Denver flight options. Last updated on September 24, 2026.
Other flights from St. Louis
Browse through other flights departing from St. Louis. Flights are based on user searches made on Cheapflights and were last updated on September 24, 2026.
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Check out other popular destinations found by fellow travelers in 2026
Top 3 airlines flying from St. Louis to Denver
Discover the top 3 airlines that operate flights from St. Louis to Denver. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 7,457,451 searches. Data last updated September 24, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$58 | Average$182 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$185 | Average$337 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$196 | Average$354 | FlexibilityNo cancel fee | On-time63% |