St Louis (STL) to Denver (DEN) flights

Southwest Airlines, United Airlines, Frontier Airlines fly nonstop from St. Louis Lambert International Airport to Denver International Airport, with about 83 flights a week in July 2026. The 770-mile flight takes about 2h 19m gate to gate.

From

STL

St Louis

St. Louis Lambert International Airport

DEN

Denver

Denver International Airport

Distance: 770 mi · 1,239 km
Flight time: 2h 19m
Airlines: 3
Seats filled: 80%

Flights a week, July 2026

3,659 flights and 480,541 passengers in 12 months

Map data: Natural Earth. Lines follow the shortest (great-circle) path.

Airlines flying STL to DEN

Airline	Flights a week	Aircraft	Passengers (12 months)	Flight time
Southwest Airlines	49	Boeing 737 MAX 8, Boeing 737-800, Boeing 737-700 / MAX 7	286,009	2h 15m
United Airlines	27	Boeing 737-800, Airbus A319, Airbus A320-100/200	140,863	2h 25m
Frontier Airlines	7	Airbus A321, Airbus A320neo, Airbus A320-100/200	48,226	2h 27m
SkyWest AirlinesSeasonal or ended	n/a	Embraer E175	5,443	2h 26m

Airlines are the operating carrier: regional airlines such as SkyWest or Horizon often fly under a larger airline's brand.

STL to DEN flight schedule

20 flight numbers flew this route in August 2026, 8 of them almost daily. The first usually leaves at 5:10am and the last at 8:45pm. Times are local and can change; check with the airline before you book.

Flight	Departs	Arrives	Days flown in August 2026	On time (12 months)
UA 362United Airlines	5:10am	6:32am	10	90%
UA 5468United Airlines · operated by SkyWest Airlines	5:10am	6:43am	9	n/a
WN 3826Southwest Airlines	7:00am	8:15am	28	100%
WN 3827Southwest Airlines	8:30am	9:45am	28	75%
UA 2459United Airlines	9:00am	10:31am	31	92%
WN 225Southwest Airlines	9:45am	11:00am	4	n/a
WN 3828Southwest Airlines	12:45pm	2:00pm	12	67%
UA 1380United Airlines	1:36pm	3:00pm	31	85%
WN 3829Southwest Airlines	2:00pm	3:15pm	16	63%
WN 1678Southwest Airlines	2:15pm	3:30pm	4	83%
WN 985Southwest Airlines	4:05pm	5:20pm	6	n/a
UA 333United Airlines	4:40pm	6:10pm	21	64%
WN 3294Southwest Airlines	4:40pm	5:55pm	4	n/a
UA 1483United Airlines	4:48pm	6:23pm	10	56%
WN 187Southwest Airlines	5:20pm	6:35pm	4	n/a
WN 3831Southwest Airlines	5:30pm	6:45pm	24	39%
WN 2704Southwest Airlines	6:05pm	7:20pm	16	50%
UA 531United Airlines	6:59pm	8:26pm	6	n/a
F9 4567Frontier Airlines	8:08pm	9:44pm	25	74%
WN 3832Southwest Airlines	8:45pm	10:00pm	24	46%

Is STL to DEN on time?

From September 2025 to August 2026, 75% of 3,687 flights arrived within 15 minutes of schedule and 0.3% were cancelled. Flights leaving around 5am were the most punctual (90%), those around 5pm the least (47%). Most delay time was caused by late-arriving aircraft (41%).

Airline	Flights	On time	Average delay	Cancelled
Southwest Airlines	2,190	73%	18 min	0.1%
United Airlines	1,205	80%	18 min	0.7%
Frontier Airlines	292	75%	24 min	0.7%

Airlines as sold: flights operated by regional partners count under the airline on the ticket. Average delay is across all completed flights, early arrivals counted as zero.

On-time arrivals by departure time

Scheduled departure	Flights	On time
5am to 6am	345	90%
6am to 7am	166	96%
7am to 8am	113	93%
8am to 9am	290	84%
9am to 10am	310	84%
10am to 11am	90	82%
11am to 12pm	134	81%
12pm to 1pm	153	82%
1pm to 2pm	337	82%
2pm to 3pm	221	79%
3pm to 4pm	135	68%
4pm to 5pm	368	56%
5pm to 6pm	215	47%
6pm to 7pm	266	56%
7pm to 8pm	179	75%
8pm to 9pm	202	72%
9pm to 10pm	119	65%

Flights by month

Month	Flights	Passengers
August 2025	327	42,758
September 2025	325	43,058
October 2025	334	44,533
November 2025	274	35,362
December 2025	265	35,119
January 2026	250	29,435
February 2026	250	29,505
March 2026	317	39,965
April 2026	285	36,172
May 2026	310	42,857
June 2026	354	50,627
July 2026	368	51,150

Source: US Department of Transportation, T-100 Segment data, August 2025 to July 2026.