Airport Tips & Quick Reference Guide to Seattle–Tacoma Airport - Seatac (SEA)

WN3856 Southwest Airlines - Flight Status

Warning
There is more than one flight with the same flight number on the same day. This is the other flight:
WN3856 Denver (DEN) to Seattle (SEA) Departure: 09:10 pm Arrival: 11:10 pm Check flight

Below, you can find details about Southwest Airlines flight WN3856, which currently operates between the airports of Denver - Denver International Airport (Airport Code DEN) and Seattle - Seattle-Tacoma International Airport (Airport Code SEA).
This flight data pertains specifically to the flight's details for Sunday, July 19, 2026.

WN3856 On Time performance:
17
We have calculated the percentage of flights that arrived within 15 minutes of their scheduled time, or earlier, based on real flight data from the last 3 months. More about punctuality and delays

Flight Status

WN3856 Southwest Airlines from Denver

Landed - On-time
Delay: 1 minutes
Flight Status for Sunday July 19, 2026
This flight is also scheduled for Tomorrow (July 20, 2026). See it here

Airline information

Southwest Airlines
Southwest Airlines
Equipment: Boeing 737-700 (winglets) Passenger/BBJ1

Departure

Denver (DEN)
July 18, 2026
Denver International Airport
Departed at:
10:38 pm
Terminal:
-
Gate:
C47
Scheduled Departure Time: 10:20 pm

Arrival

Seattle (SEA)
July 19, 2026
Seattle-Tacoma International Airport
Arrived at:
12:16 am
Gate:
S8A
Scheduled Arrival Time: 12:15 am
Baggage: 11
Disclaimer
The information displayed on this website is gathered from third-party providers with a wide reputation on the sector, which in turn obtain the information from the airlines. This data is provided only for informative purposes. www.seattle-airport.com assumes no responsibility for loss or damage as a result of relying on information posted here. Please contact your airline to verify flight status.

Additional Information

Which is the frequency of flight WN3856?
The flight WN3856 is scheduled to flight on Monday, Tuesday, Wednesday, Thursday, Friday, Sunday on a weekly basis.

Which is the distance of flight WN3856?
The distance between the two airports is 1022 miles.

Which is the flight time of flight WN3856?
The scheduled flight time gate to gate is: 02:55 hours.
The real flight time gate to gate on average is: 02:51 hours.

Are the departure airport and arrival airport at the same Time Zone?
No, each airport is in a different timezone. The times shown above, are presented in the local time of each respective airport.
Current Time in Denver: 2026-07-19 10:19:09
Current Time in Seattle: 2026-07-19 09:19:09

Alternative Flights

The following airlines serves the same route between Denver and Seattle:

Alaska Airlines
- Flight Number: AS249. (On Time performance: 66 - Average Delay: 18 minutes)
- Flight Number: AS317. (On Time performance: 79 - Average Delay: 15 minutes)
- Flight Number: AS381. (On Time performance: 83 - Average Delay: 9 minutes)
- Flight Number: AS493. (On Time performance: 87 - Average Delay: 6 minutes)
- Flight Number: AS535. (On Time performance: 67 - Average Delay: 38 minutes)
- Flight Number: AS643. (On Time performance: 91 - Average Delay: 11 minutes)

Air Transport International
- Flight Number: 8C3395. (On Time performance: 16 - Average Delay: 36 minutes)

Delta Air Lines
- Flight Number: DL1358. (On Time performance: 85 - Average Delay: 7 minutes)
- Flight Number: DL1731. (On Time performance: 98 - Average Delay: 6 minutes)
- Flight Number: DL2543. (On Time performance: 60 - Average Delay: 34 minutes)

Frontier Airlines
- Flight Number: F91175. (On Time performance: 87 - Average Delay: 8 minutes)
- Flight Number: F94545. (On Time performance: 85 - Average Delay: 11 minutes)

United Airlines
- Flight Number: UA1424. (On Time performance: 86 - Average Delay: 9 minutes)
- Flight Number: UA1482. (On Time performance: 94 - Average Delay: 3 minutes)
- Flight Number: UA2013. (On Time performance: 73 - Average Delay: 13 minutes)
- Flight Number: UA2164. (On Time performance: 81 - Average Delay: 9 minutes)
- Flight Number: UA2271. (On Time performance: 93 - Average Delay: 4 minutes)
- Flight Number: UA2651. (On Time performance: 73 - Average Delay: 24 minutes)
- Flight Number: UA360. (On Time performance: 69 - Average Delay: 16 minutes)

Southwest Airlines
- Flight Number: WN1713. (On Time performance: 75 - Average Delay: 11 minutes)
- Flight Number: WN1716. (On Time performance: 34 - Average Delay: 40 minutes)
- Flight Number: WN1780. (On Time performance: 60 - Average Delay: 15 minutes)
- Flight Number: WN3051. (On Time performance: 56 - Average Delay: 16 minutes)
- Flight Number: WN4030. (On Time performance: 40 - Average Delay: 26 minutes)
- Flight Number: WN4130. (On Time performance: 31 - Average Delay: 24 minutes)
- Flight Number: WN760.

Punctuality and delays

We have gathered data from recent months and present below an analysis of how timely the flights have been.

In terms of On-Time Performance, by analyzing the flight data from the last three months, spanning from June 04, 2026 to July 10, 2026, we have obtained these figures.
Total number of flights: 36
On Time: 6 ( 17 % )
Moderate Delay: 4 ( 11 % )
Significant Delay: 13 ( 36 % )
Major Delay: 13 ( 36 % )
Canceled: 0 ( 0 % )
Diverted: 0 ( 0 % )

Average Delay: 54 minutes.
Delays analyzed by Weekday: We have gathered available data from last six months, spanning from June 04, 2026 to July 10, 2026. Next, you can observe the results broken down by day of the week: number of flights analyzed, on-time performance per day, and average delay per day.

Delays analyzed by Month: We have gathered available data from last twelve closed months, spanning from June 04, 2026 to June 30, 2026. Next, you can observe the results broken down by month: number of flights analyzed, on-time performance per month, and average delay per month.

Last Past Flights WN3856

Date
Departure
Arrival
Duration
Aircraft
Status
Friday
17 July
10:23 pm
Denver (DEN)
11:55 pm
Seattle (SEA)
02h 32min
Boeing 737MAX
Boeing 737MAX
Landed - Delayed
Thursday
16 July
10:11 pm
Denver (DEN)
12:07 am
Seattle (SEA)
02h 56min
Boeing 737-800
Boeing 737-800
Landed - Delayed
Wednesday
15 July
09:34 pm
Denver (DEN)
11:26 pm
Seattle (SEA)
02h 52min
Boeing 737MAX
Boeing 737MAX
Landed - On-time
Tuesday
14 July
09:36 pm
Denver (DEN)
11:24 pm
Seattle (SEA)
02h 48min
Boeing 737MAX
Boeing 737MAX
Landed - On-time
Monday
13 July
09:28 pm
Denver (DEN)
11:02 pm
Seattle (SEA)
02h 34min
Boeing 737-800
Boeing 737-800
Landed - On-time
Sunday
12 July
09:17 pm
Denver (DEN)
11:01 pm
Seattle (SEA)
02h 44min
Boeing 737MAX
Boeing 737MAX
Landed - On-time
Sunday
12 July
11:21 pm
Denver (DEN)
01:04 am
Seattle (SEA)
02h 43min
Boeing 737-700
Boeing 737-700
Landed - Delayed
Friday
10 July
11:15 pm
Denver (DEN)
12:55 am
Seattle (SEA)
02h 40min
Boeing 737-800
Boeing 737-800
Landed - Delayed
Thursday
09 July
10:45 pm
Denver (DEN)
12:24 am
Seattle (SEA)
02h 39min
Boeing 737-800
Boeing 737-800
Landed - Delayed
Wednesday
08 July
11:28 pm
Denver (DEN)
01:02 am
Seattle (SEA)
02h 34min
Boeing 737-800
Boeing 737-800
Landed - Delayed