AirHint found the following cheapest one-way flights from Seattle (SEA) to San Juan (SJU) in December 2025 (see full year).
One-Way flights
| 31 Dec | Sun Country Airlines | ||
| 29 Dec | Frontier Airlines | ||
| 25 Dec | Frontier Airlines | ||
| 22 Dec | Delta | ||
| 26 Dec | Sun Country Airlines | ||
| 28 Dec | Sun Country Airlines | ||
| 23 Dec | Sun Country Airlines |
Also check the deals for return 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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