I highly recommend taking 3-6 hours of your day one of the days while you're in Costa Rica to visit Cahuita National Park & Punta Cahuita. You will be blown away by the nature and the beauty. Make sure you pack water, snacks, beach clothes and snorkeling gear once you get to the furthest point of the "Punta" or peninsula.
This is a great place to enjoy a meal or get a drink. My favorite is the Coco Loco and the famous rice and beans! Fun fact: Dennis (The Best Man), and his family own this bar and restaurant!