Los Chorros Municipal Recreation Park (Parque Recreativo Municipal Los Chorros) is a nice park where you can enjoy 2 big waterfalls. You can safely park your car and after a small 20 mins hike you can reach the fist waterfall. Then if you walk 10 more minutes you can find the second and largest waterfall. This place is perfect for one day trip from San José. They have picnic areas so you can bring your own food.
The first waterfall in which you can swim.