Cheapest return flights from Seattle (SEA) to Denver (DEN), September

Select a price to book. see full year.

Dates, airline, and price
Dates Airline Price
02 Sep 16 Sep Frontier Airlines
Direct Flight
01 Sep 16 Sep Frontier Airlines
Direct Flight
12 Sep 15 Sep Frontier Airlines
Direct Flight
09 Sep 16 Sep Frontier Airlines
Direct Flight
01 Sep 09 Sep Frontier Airlines
Direct Flight
29 Sep 06 Oct Frontier Airlines
Direct Flight
04 Sep 08 Sep Frontier Airlines
Direct Flight
08 Sep 13 Sep Frontier Airlines
Direct Flight
17 Sep 20 Sep Frontier Airlines
Direct Flight
24 Sep 27 Sep Frontier Airlines
Direct Flight
18 Sep 20 Sep Frontier Airlines
Direct Flight
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deals for one-way flights from Seattle to Denver in September.

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Updated Jun 14, 2026.

About these fares

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