Roughly 45min away from San Jose, this is a must stop if you're staying anywhere in central Costa Rica. $45 per person to get in but absolutely worth it. Secure and safe parking lot out front. Once inside you have about 45min of animal habitats to walkthrough. Some of the healthiest animals I've seen in captivity with large enclosures. Continue on main trail and you get more of a hiking feel through a trail that goes past numerous waterfalls. All roughly paved and stepped, but fairly steep. You're both at eye level of the falls and down on the river's shores so excellent picture opportunities. After main trail (~2 hours total) there is a restaurant and gift shop along with a bus that takes you back to front. There is also a lake with more trails and a sit-down restaurant on the other side of the property.
Beautiful drive to and from the park as well. Excellent part of Costa Rica