AirHint found the following cheapest return flights from Phoenix (PHX) to Denver (DEN) in December 2025 (see full year).

Return flights

04 Dec - 07 Dec	Frontier Airlines	direct
14 Dec - 18 Dec	Frontier Airlines	direct
24 Dec - 31 Dec	Southwest Airlines	direct
17 Dec - 20 Dec	United	direct
17 Dec - 02 Jan	American Airlines	direct
23 Dec - 27 Dec	United	direct
24 Dec - 27 Dec	United	direct
30 Dec - 02 Jan	American Airlines	direct
23 Dec - 26 Dec	United	direct

Also check the deals for one-way flights from Phoenix to Denver in December.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from Phoenix to Denver in December from $88

Return flights