7 Best Sights in The Osa Peninsula and the South Pacific, Costa Rica

Named for the whales who use this area as a nursery, the park has four separate Blue Flag beaches stretching for about 10 km (6 miles) and encompasses a mangrove estuary, a remnant coral reef, and more than 12,350 acres of ocean, home to tropical fish, dolphins, and humpback whales. Playa Uvita is the most popular sector of the park, with the longest stretch of beach and shallow waters calm enough for kids. Restaurants line the road to the Playa Uvita park entrance, but there are no food concessions within the park. Access to each of the four beaches—from north to south, Uvita, Colonia, Ballena, and Piñuela—is off the Costanera Highway. Although the official park offices are open 7 am to 6 pm, visitors can stay on longer, especially to view sunsets or camp.

This leading ecotourism and conservation wildlife refuge offers spectacular bird-watching tours and excellent naturalist-led hikes (starting at $36), a thrilling Flight of the Toucan canopy tour ($52), a chance to spend the night in the jungle ($158), or self-guided walks along forest and mangrove trails ($15). The refuge also manages a turtle-protection project and nature-education program in the local school. You can stay in basic cabins or in poolside rooms—or just come for the day.

This massive double cascade, the longer one tumbling down 150 feet, is one of the most spectacular sights in Costa Rica. The falls (aka Barú River Falls) are on private property, so the only ways to reach them are on horseback, hiking, or riding in an open truck. Arrive before 1 pm as access to the waterfalls closes at 2 pm.

This private nature reserve staffed by volunteers and a senior biologist has an easy trail to a waterfall, plus almost 12 km (8 miles) of river and ridge trails, including one trail that utilizes 4 km (2½ miles) of the Chirripó National Park trail. It's a pleasant alternative for hikers who aren't up to the challenge of Chirripó or haven't reserved a spot far in advance. You can take a guided 3½-hour tour past two waterfalls and learn about the flora and fauna of the cloud forest for $35. There's also an art gallery featuring nature paintings by artist Linda Moskalyk, and accommodations in four fully equipped houses (starting at $70, two-night minimum). Volunteers often occupy the simple rental cabins, so check the website for availability. There's no admission fee to hike in the reserve, but donations are requested.

With more than 300 specimens, this impressive collection includes snakes, lizards, frogs, turtles, and other reptilian creatures, housed in visitor-friendly terrariums and large enclosures. Stars of the exhibit are a Komodo dragon, Gila monsters, and a 150-pound African spur-thighed tortoise that likes to be petted. Kids love the maternity ward showcasing newborn snakes. More mature snakes live under a retractable roof that lets in sun and rain. Although snakes are generally more active in sunlight, this is still a great rainy-day activity. Guided night tours can also be arranged to watch nocturnal animals. If you're not squeamish, snake-feeding day is Friday, spread out from 10 am to 3 pm.

Hidden in a forest above Dominicalito Beach, this waterfall is considerably smaller than Nauyaca Waterfalls, but it has a lovely swimming hole at its base. The pool is often populated by local kids when school is out and by surfers late in the afternoon. Pay strict attention to the posted sign that warns not to leave anything of value in your parked car. Avoid holiday times and weekends, when there are often large crowds. The best time to visit is during rainy season between the months of June and December.

Ride the range on a 1,250-acre property combining forest and pasture ($55) or gallop along the beach at sunset on horseback ($60). Riding tours also include a guide and helmets, and kid-size saddles are available. All tours begin at the pleasant reception center, where you can freshen up in clean, modern restrooms. For $8 you can explore the 10 km (6 miles) of hiking trails on your own with a trail map that includes a wildlife picture guide.