AirHint found the following cheapest return flights from Seattle (SEA) to Guadalajara (GDL) in December 2025 (see full year).

Return flights

02 Dec - 11 Dec	Hawaiian Airlines
08 Dec - 15 Dec	Hawaiian Airlines
15 Dec - 14 Jan	Alaska Airlines
15 Dec - 07 Jan	Alaska Airlines
16 Dec - 07 Jan	Alaska Airlines
19 Dec - 26 Dec	Frontier Airlines
19 Dec - 26 Dec	Delta	direct

Also check the deals for one-way flights from Seattle to Guadalajara 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 Seattle to Guadalajara in December from 342€

Return flights