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

Return flights

03 Dec - 04 Dec	Aeromexico	direct
08 Dec - 22 Dec	Aeromexico
22 Dec - 26 Dec	Air Canada
23 Dec - 30 Dec	Alaska Airlines
25 Dec - 31 Dec	Air Canada
26 Dec - 31 Dec	Air Canada
22 Dec - 27 Dec	WestJet
23 Dec - 29 Dec	Alaska Airlines
20 Dec - 22 Dec	Sun Country Airlines
26 Dec - 01 Jan	Air Canada
22 Dec - 29 Dec	Sun Country Airlines
20 Dec - 03 Jan	Air Canada
26 Dec - 04 Jan	Air Canada
26 Dec - 03 Jan	Air Canada
17 Dec - 02 Jan	WestJet
26 Dec - 01 Jan	Alaska Airlines	direct
26 Dec - 04 Jan	Delta	direct
26 Dec - 03 Jan	Alaska Airlines	direct

Also check the deals for one-way flights from Seattle to Cancun 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 Cancun in December from $374

Return flights