The beach trail that connects La Leona and Sirena ranger stations follows the rugged Pacific coastline. The beach winds off the beach into the edge of the forest so that much of the hike is shaded. The portions of the trail that lie upon the beach offer no shade, and the walking can be made more difficult by dry sand when the hike is taken as the tide is rising.
Two rivers must be crossed during this hike. The Madrigal River, 2.5 kilometers from the La Leona entrance is unlikely to be deeper than waist deep at the most, even at high tide. The Rio Claro, which is only a kilometer or so from Sirena can reach chest high at high tide and is best traversed during periods of low tide. However, even at high tide it is not particularly dangerous. All Corcovado rivers are likely to have occasional crocodiles, and bull sharks feed at the mouths of all rivers, preying indiscriminately in the turbid mixing zone between fresh and salt water. Perhaps more treacherous than large predators, the swift current at the mouths of these rivers may be capable of knocking you off balance. Caution should be exercised at all river crossings.
The Sirena-La Leona hike is rated at 17 kilometers, plus another 2.5 kilometers that separate La Leona and Carate. When the sun is out, this hike can be particularly arduous, and care should be taken to bring plenty of water and sunscreen as needed. A hat is a necessity for this trail.