Cheapest return flights from Seattle to San Juan in December from 356€

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

Return flights

04 Dec - 07 Dec Frontier Airlines
10 Dec - 15 Dec United
30 Dec - 13 Jan United
03 Dec - 08 Dec United
10 Dec - 14 Dec United
22 Dec - 31 Dec Frontier Airlines
22 Dec - 30 Dec Frontier Airlines
22 Dec - 29 Dec Frontier Airlines
29 Dec - 04 Jan Frontier Airlines
28 Dec - 04 Jan Sun Country Airlines
17 Dec - 02 Jan Sun Country Airlines
18 Dec - 02 Jan Frontier Airlines
24 Dec - 31 Dec Sun Country Airlines
26 Dec - 04 Jan Frontier Airlines

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

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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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