Seattle to Denver in September 2026

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

Lowest this month $79

Highest this month $128

Sample fare $79

Airports SEA–DEN

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September 2026 price calendar

From $79 · up to $128

Mon

Tue

Wed

Thu

Fri

Sat

Sun

2 $128 3 $128 4 $128 5 $128 6 $126 7 $126 8 $126 9 $126 10 $126 11 $126 12 $126 13 $126 14 $125 15 $102 16 $102 17 $102 18 $102 19 $79

Denver DEN

$79

Sep 19, 4:27pm · 2h 54m · 0 stops

SEA → DEN · Frontier Airlines

Denver DEN

$125

Sep 14, 9:45pm · 11h 22m · 1 stop

SEA → DEN · Frontier Airlines

This page is only September 2026 on the Seattle to Denver 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 Seattle to Denver in September 2026.