AirHint found the following cheapest return flights from Phoenix (PHX) to Seattle (SEA) in March 2026 (see full year).

Return flights

05 Mar - 09 Mar	Frontier Airlines	direct
10 Mar - 13 Mar	Delta	direct
27 Mar - 01 Apr	Frontier Airlines	direct
26 Mar - 31 Mar	Southwest Airlines
08 Mar - 11 Mar	Frontier Airlines	direct
29 Mar - 06 Apr	Frontier Airlines	direct
16 Mar - 20 Mar	Southwest Airlines
16 Mar - 20 Mar	American Airlines	direct

Also check the deals for one-way flights from Phoenix to Seattle in March.

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 Seattle in March from $38

Return flights