* Drinking water: The water at the ranger station is potable, but if you are concerned, bring some type of water purifier. The park recommends you carry 1.5 liters of water for the La Leona and Los Patos hike, but I've seen my guests drink this within the first 2 hours. Know your self and your water needs, dehydration and heat-exhaustion are common illnesses in the park.
* Sunscreen: It's recommended to use sunscreen, a hat, and long sleeved shirt on the hike from Sirena to La Leona. While much of the hike is through the jungle, there are long stretches along the beach that benefit from sun protection.
* Insect Repellent: Recent outbreaks of Dengue Fever in Costa Rica are a concern. Currently there is no Malaria to be worried about. Also, bug spray helps with the sand flies and no-see-ums...
* Solo Hiking? No: It's best to hike with a guide or a hiking buddy. There are several tricky river crossings and tricky rocky ocean/beach crossings that need to be navigated at low tide...
* Don't hike off-trail: Each year people try to bushwack their way to discovered areas of Corcovado, and each year the local community has to preform rescue missions to find them when they go missing. For your safety and the safety of others, it's best to stick to the marked trails.
* No Swimming: Crocodiles and Bullsharks rule the ocean here and love to swim at the mouth of rivers. In addition, the currents and tides are quite powerful.
* River Crossings: Cross carefully and quickly, and never risk crossing the rivers at high tide or during heavy rain.
* Snakes: Watch where you step and touch. There are Fer de Lance and other poisonous snakes in the region. Be especially careful around rivers and streams where they come to eat frogs, especially at night.
* Ants: Seemingly harmless, their bites sting for up to one hour...
* Peccaries/Wild Pigs. There are two different species of peccaries in Corcovado, the Collared and the White-lipped Peccary. They run in packs and can be very aggressive. If threatened by a group of peccaries, climb a tree until you are six feet or higher off the ground.
Written and contributed by Jaguardman