To save up to 7% on this flight, we recommend booking at least 19 days prior to travel. The price may fluctuate and will likely increase closer to your departure date. Users on Cheapflights have found tickets from Kalispell to Puerto Rico from $262 1-2 weeks out and tickets from $281 for flights departing within the next 72 hours.
Due to multiple factors, expect to potentially pay more when booking in December. For low rates, August can be a great choice for travel to Puerto Rico. Flights to Puerto Rico from Kalispell in August are about $313 on average during August, but can be found for as low as $121.