Denver to Seattle in September 2026

Dated one-way fares from Denver to Seattle in September 2026. Use the calendar to see which days are cheaper.

Lowest this month $116

Highest this month $128

Sample fare $94

Airports DEN–SEA

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September 2026 price calendar

From $116 · up to $128

Mon

Tue

Wed

Thu

Fri

Sat

Sun

2 $128 3 $124 4 $120 5 $120 6 $120 7 $120 8 $120 9 $120 10 $120 11 $120 12 $120 13 $120 14 $116

Seattle SEA

$94

Oct 01, 1:07pm · 3h 1m · 0 stops

DEN → SEA · Frontier Airlines

This page is only September 2026 on the Denver to Seattle route. Open the full route if you want the next months side by side.

Prices move as seats sell. Confirm the live itinerary before you book Denver to Seattle in September 2026.