Cheapest return flights from Seattle to San Juan in December from $278

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

Return flights

06 Dec - 13 Dec Frontier Airlines
08 Dec - 12 Dec Frontier Airlines
09 Dec - 15 Dec American Airlines
04 Dec - 08 Dec Frontier Airlines
11 Dec - 14 Dec Frontier Airlines
10 Dec - 14 Dec Alaska Airlines
22 Dec - 31 Dec Frontier Airlines
21 Dec - 25 Dec Frontier Airlines
22 Dec - 06 Jan Frontier Airlines
29 Dec - 05 Jan Frontier Airlines
03 Dec - 26 Dec Alaska Airlines
23 Dec - 31 Dec Frontier Airlines
26 Dec - 01 Jan Sun Country Airlines
20 Dec - 06 Jan Sun Country Airlines
23 Dec - 01 Jan Frontier Airlines
24 Dec - 01 Jan Frontier Airlines
22 Dec - 05 Jan Frontier Airlines
27 Dec - 10 Jan American Airlines
24 Dec - 02 Jan Frontier Airlines
23 Dec - 02 Jan Frontier Airlines

Also check the deals for one-way flights from Seattle to San Juan in December.

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