Denver (DEN) to Seattle (SEA) flights

United Airlines, Alaska Airlines, Southwest Airlines, Delta Air Lines, Frontier Airlines fly nonstop from Denver International Airport to Seattle-Tacoma International Airport, with about 153 flights a week in July 2026. The 1,024-mile flight takes about 2h 58m gate to gate.

From

DEN

Denver

Denver International Airport

SEA

Seattle

Seattle-Tacoma International Airport

Distance: 1,024 mi · 1,648 km
Flight time: 2h 58m
Airlines: 5
Seats filled: 87%

Flights a week, July 2026

6,293 flights and 912,276 passengers in 12 months

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

Airlines flying DEN to SEA

Airline	Flights a week	Aircraft	Passengers (12 months)	Flight time
United Airlines	46	Boeing 737-800, Boeing 737-900ER, Airbus A320-100/200	285,190	2h 57m
Alaska Airlines	38	Boeing 737-900ER, Boeing 737 MAX 9, Boeing 737-800	238,198	3h 0m
Southwest Airlines	34	Boeing 737 MAX 8, Boeing 737-800, Boeing 737-700 / MAX 7	207,039	2h 55m
Delta Air Lines	21	Airbus A220-300, Airbus A220-100, Boeing 737-800	86,816	2h 58m
Frontier Airlines	14	Airbus A321, Airbus A320neo, Airbus A320-100/200	80,781	3h 1m
SkyWest AirlinesSeasonal or ended	n/a	Embraer E175	14,252	3h 10m

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

DEN to SEA flight schedule

36 flight numbers flew this route in August 2026, 12 of them almost daily. The first usually leaves at 6:00am and the last at 9:08pm. 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 1482United Airlines	6:00am	8:00am	10	93%
AS 643Alaska Airlines	6:02am	8:05am	18	90%
DL 1731Delta Air Lines	6:20am	8:19am	31	89%
F9 4545Frontier Airlines	7:15am	9:19am	31	83%
UA 2271United Airlines	8:02am	10:01am	31	92%
AS 317Alaska Airlines	8:40am	10:42am	31	79%
WN 4870Southwest Airlines	8:45am	10:40am	4	n/a
WN 4462Southwest Airlines	9:05am	11:00am	8	n/a
WN 883Southwest Airlines	9:15am	11:10am	12	50%
UA 2757United Airlines	9:45am	11:44am	18	72%
F9 1175Frontier Airlines	11:00am	1:17pm	31	84%
UA 1424United Airlines	11:21am	1:21pm	10	86%
UA 2058United Airlines	11:23am	1:22pm	21	86%
WN 888Southwest Airlines	11:25am	1:20pm	12	33%
AS 682Alaska Airlines	12:02pm	2:00pm	13	84%
AS 381Alaska Airlines	12:55pm	2:53pm	18	74%
WN 1536Southwest Airlines	1:00pm	2:55pm	12	25%
DL 1358Delta Air Lines	1:21pm	3:23pm	31	77%
UA 464United Airlines	1:55pm	3:52pm	15	67%
UA 2164United Airlines	2:00pm	4:00pm	8	80%
WN 1670Southwest Airlines	3:40pm	5:35pm	20	15%
UA 2013United Airlines	3:45pm	5:42pm	31	78%
WN 4514Southwest Airlines	4:15pm	6:10pm	8	n/a
WN 4980Southwest Airlines	4:20pm	6:15pm	5	n/a
AS 535Alaska Airlines	4:36pm	6:38pm	30	64%
WN 3544Southwest Airlines	4:45pm	6:40pm	4	n/a
AS 309Alaska Airlines	5:34pm	7:34pm	11	46%
AS 249Alaska Airlines	6:15pm	8:17pm	17	48%
DL 2543Delta Air Lines	6:43pm	8:45pm	31	53%
WN 555Southwest Airlines	6:50pm	8:45pm	12	0%
UA 360United Airlines	7:14pm	9:15pm	31	65%
AS 615Alaska Airlines	7:30pm	9:30pm	13	62%
WN 3415Southwest Airlines	8:55pm	10:55pm	12	30%
UA 2651United Airlines	9:03pm	11:04pm	19	68%
WN 4800Southwest Airlines	9:05pm	11:05pm	12	58%
AS 493Alaska Airlines	9:08pm	11:10pm	12	46%

Is DEN to SEA on time?

From September 2025 to August 2026, 75% of 6,328 flights arrived within 15 minutes of schedule and 0.6% were cancelled. Flights leaving around 7am were the most punctual (90%), those around 6pm the least (56%). Most delay time was caused by late-arriving aircraft (43%).

Airline	Flights	On time	Average delay	Cancelled
United Airlines	1,908	81%	12 min	0.5%
Alaska Airlines	1,551	75%	16 min	0.7%
Southwest Airlines	1,342	60%	22 min	0.3%
Delta Air Lines	1,088	78%	19 min	0.8%
Frontier Airlines	439	83%	10 min	1.1%

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
6am to 7am	612	89%
7am to 8am	516	90%
8am to 9am	631	84%
9am to 10am	225	78%
11am to 12pm	472	83%
12pm to 1pm	509	75%
1pm to 2pm	399	79%
3pm to 4pm	399	71%
4pm to 5pm	352	67%
5pm to 6pm	162	65%
6pm to 7pm	411	56%
7pm to 8pm	741	66%
8pm to 9pm	274	63%
9pm to 10pm	338	59%

Flights by month

Month	Flights	Passengers
August 2025	642	99,911
September 2025	575	83,860
October 2025	549	78,689
November 2025	457	63,630
December 2025	468	66,293
January 2026	434	57,337
February 2026	401	53,545
March 2026	447	62,673
April 2026	469	64,414
May 2026	547	82,096
June 2026	629	95,277
July 2026	677	104,750

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