Poipū Beach Park is consistently rated among the best beaches in the United States, and the accolades are justified: calm water on one side of a tombolo (a sand bar connecting the shore to a small rocky island) provides safe swimming even for children, while the more exposed side has waves suitable for beginning surfers. The water is warm, clear, and reliably sunny — the south shore of Kauai gets significantly less rain than the famous wet north coast.
Hawaiian monk seals, one of the most endangered marine mammals in the world, regularly haul out on the beach to rest — the park rangers put up a small cordon when this happens, and watching a monk seal snooze in the sun at close range while tourists photograph from a respectful distance is one of those Hawaii experiences that stays with you. Green sea turtles are also common in the shallows. Arrive early to get parking and a patch of sand before the resort crowds build up.