On Kauai’s South Shore, there’s always plenty going on at the popular Poipu Beach, which has been ranked among the best in the U.S. Its waters entice swimmers, snorkelers, and experienced surfers. Monk seals, sea turtles, and, from December through May, humpback whales are among the creatures you might spot; snorkeling, of course, offers encounters with the fish kind. Lifeguards are on duty here. Baby Beach, just to the west of Poipu Beach, has a protected cove that makes it perfect for the littles.