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

Return flights

31 Dec - 06 Jan	Frontier Airlines
24 Dec - 30 Dec	United
24 Dec - 31 Dec	United
23 Dec - 27 Dec	Delta
24 Dec - 01 Jan	Aeromexico
31 Dec - 03 Jan	Aeromexico
26 Dec - 30 Dec	Frontier Airlines
30 Dec - 04 Jan	Frontier Airlines	direct
24 Dec - 30 Dec	Southwest Airlines	direct
24 Dec - 01 Jan	Southwest Airlines	direct
29 Dec - 02 Jan	Delta
31 Dec - 06 Jan	Southwest Airlines	direct
23 Dec - 27 Dec	Southwest Airlines	direct
26 Dec - 30 Dec	Southwest Airlines	direct
29 Dec - 02 Jan	Frontier Airlines	direct

Also check the deals for one-way flights from St. Louis 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 St. Louis to Cancun in December from $432

Return flights