Seattle–Tacoma International Airport
Seattle, United StatesSEA / KSEA
International hub · 132 direct destinations · 3 runways · longest runway 11,900 ft
48 °F · ClearSource: METAR observation via the NOAA Aviation Weather Center
Route
Seattle → Denver
SEA
SeattleSeattle–Tacoma International Airport
SeattleSeattle–Tacoma International AirportDENDenverDenver International Airport
DenverDenver International Airport- Distance
- 1,022 mi
- Estimated flight time
- ~2h 35m
Denver is currently 1 hour ahead of Seattle.
Observed nonstop
How often does this route fly?
Frequency
Throughout the day
On average around 17 flights a day, observed from October 2025 to September 2026.
- 17
- flights per day
- 21
- busiest month · Jun
- 14
- quietest month · Dec
- 2 hr 9 min
- measured flight time
- 12 / 12
- months seen
Through the year
Per day, month by month
- 14Jan2026
- 15Feb
- 15Mar
- 16Apr
- 18May
- 21Jun
- 21Jul
- 20Aug
- 19.5Sep
- 18Oct2025
- 16Nov
- 14Dec
Airlines
Who flies it
United Airlinesall year
Alaska Airlinesall year
Southwest Airlinesall year
Delta Air Linesall year
Frontier Airlinessummer
Air Transport Internationalall year
SkyWest Airlineswinter
Through the day
Departure times
Local time in Seattle. Most departures between 13:00 and 16:00.
- 00:00
- 01:00
- 02:00
- 03:00
- 04:00
- 05:00
- 06:00
- 07:00
- 08:00
- 09:00
- 10:00
- 11:00
- 12:00
- 13:00
- 14:00
- 15:00
- 16:00
- 17:00
- 18:00
- 19:00
- 20:00
- 21:00
- 22:00
- 23:00
Through the week
By weekday
- 18.1Mon
- 16.7Tue
- 15.9Wed
- 17.6Thu
- 17.9Fri
- 17.2Sat
- 17Sun
Fleet
Aircraft observed
- Boeing 737-800B73818%
- Boeing 737 MAX 8B38M15%
- Boeing 737-900B73914%
- Boeing 737 MAX 9B39M9%
- Airbus A321neoA21N8%
All the numbers in a table
| Month | Per day | Seen | Airlines |
|---|---|---|---|
| January 2026 | 14 | 434 |
|
| February 2026 | 15 | 416 |
|
| March 2026 | 15 | 453 |
|
| April 2026 | 16 | 469 |
|
| May 2026 | 18 | 518 |
|
| June 2026 | 21 | 635 |
|
| July 2026 | 21 | 678 |
|
| August 2026 | 20 | 597 |
|
| September 2026 | 19.5 | 577 |
|
| October 2025 | 18 | 563 |
|
| November 2025 | 16 | 462 |
|
| December 2025 | 14 | 410 |
|
Airlines observed on this route
From observed callsign routes on SEA-DEN - not a booking guarantee.
About this route
- Domestic route: both airports are in the same country.
- The opposite direction has also been observed as a direct connection.
- Direct destinations observed from Seattle: 132.
- Direct destinations observed from Denver: 203.
The airports on this route
Denver International Airport
Denver, United StatesDEN / KDEN
International hub · 203 direct destinations · 6 runways · longest runway 16,001 ft
32 °F · ClearSource: METAR observation via the NOAA Aviation Weather Center
Alternative airports for this journey
Same journey, a different airport nearby - with an observed direct connection.
BFI DENKing County International Airport - Boeing FieldSeattle is about 6 mi from Seattle.View route →PAE DENSeattle Paine Field International AirportEverett is about 32 mi from Seattle.View route →SEA COSCity of Colorado Springs Municipal AirportColorado Springs is about 73 mi from Denver.View route →
About the route from Seattle to Denver
The observed direct connection between Seattle–Tacoma International Airport (SEA) and Denver International Airport (DEN) covers approximately 1,022 mi. The estimated flight time is around 2h 35m. Air Transport International, Alaska Airlines, Delta Air Lines, Frontier Airlines, SkyWest Airlines, Southwest Airlines and United Airlines have been observed on this connection in the available route data.
Frequently asked questions about this route
- How far is Seattle from Denver by air?
- The great-circle distance between Seattle–Tacoma International Airport and Denver International Airport is approximately 1,022 mi.
- How long is the flight from Seattle to Denver?
- Based on the distance, the estimated flight time is about 2h 35m. This is an estimate, not a schedule.
- Is there a direct connection from Seattle to Denver?
- Yes, a direct connection between SEA and DEN has been observed in our route data.
- Which airlines have been observed on this route?
- In the available route data: Air Transport International, Alaska Airlines, Delta Air Lines, Frontier Airlines, SkyWest Airlines, Southwest Airlines and United Airlines.
- How often is there a flight from Seattle to Denver?
- On average around 17 flights a day, measured over twelve months (October 2025 to September 2026) in the flight archive, with 6,212 observed flights. Mainly United Airlines, Alaska Airlines, Southwest Airlines. That is an observation, not a timetable.
- What is the current time difference between Seattle and Denver?
- Denver is currently 1 hour ahead of Seattle.
Where this data comes from
The route data comes from the flight archive (ADS-B, adsb.lol): which connections actually flew over the last twelve full months and who flew them, combined with our own airport, runway, and airline datasets. It is reference data about observed routes - not a current timetable and no claim about bookability.
The frequency and aircraft on this page come from the flight archive (ADS-B, 12 months, October 2025 to September 2026), summarized per route per month. We do not see every flight, so it is a floor, not a count.
Route data updated on October 11, 2026.