Find Frontier Airlines(F9) flights from Denver to Seattle

At the moment, you can catch a nonstop flight from Denver to Seattle with the following airlines, including: Delta Air Lines Selected airlines are based on historical data collected from flight bookings users made on Trip.com within the last 90 days.

It takes about 3 hours 3 minutes to fly from Denver to Seattle.

By analyzing data from all airlines on the Trip.com flight calendar, it looks like the best time to book a flight from Denver to Seattle is around 40 days (6 weeks) in advance, and the best time to fly is usually on Tuesday, Wednesday, and Saturday. Tuesday typically offers the cheapest flights for departure, while Saturday offers the best return deals.

Based on Trip.com data in the past 4 weeks, there is 49 flight per week flying from Denver to Seattle. You can check the weekly schedule for popular airlines on this route below: Delta Air Lines: S/M/T/W/T/F/S -- DL1731 (06:31)

The cheapest months to fly from Denver to Seattle is October, when demand for travel is lower.

After crunching the numbers on our December flight calendar, it's currently cheapest to fly from Denver to Seattle on December 23, 2025 with Frontier Airlines, with prices starting at DKK 397.

You can land at any one of the following hubs in Seattle, with Denver International Airport to Seattle–Tacoma International Airport (DEN-SEA) is by far the most common option on this route: King County (Boeing Field) International Airport (BFI) Kenmore Air - Lake Union (LKE) Seattle–Tacoma International Airport (SEA).

The time difference between Seattle and Denver is 1h.

Tickets can only be changed or canceled if permitted by airline policy. To submit a change or cancellation request, go to the flight bookings page, select the option to change or cancel your booking, choose the relevant passengers and segment, and submit a request. Please note that additional charges may apply according to the airline ticket policy. However, if the flight has been rescheduled and you would like to change or cancel your ticket, you can submit an involuntary cancellation request. For more details about change and cancellation policies, please check the customer support pages.