Cheapest one-way flights from Phoenix to Seattle in December from $147

AirHint found the following cheapest one-way flights from Phoenix (PHX) to Seattle (SEA) in December 2025 (see full year).

One-Way flights

25 Dec Frontier Airlines
29 Dec Frontier Airlines
29 Dec Alaska Airlines direct
30 Dec Frontier Airlines
30 Dec Alaska Airlines direct
26 Dec Frontier Airlines
28 Dec Frontier Airlines
27 Dec Frontier Airlines
27 Dec Frontier Airlines direct
24 Dec Frontier Airlines

Also check the deals for return flights from Phoenix to Seattle in December.

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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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