A flooded volcanic crater turned nature preserve, Hanauma is effectively a giant natural aquarium: parrotfish, tangs and green turtles cruising coral heads in water rarely deeper than a snorkeller needs. Numbers are capped and reservations required, which has transformed the reef's health. Book the earliest slot, watch the mandatory conservation video with good grace, and you'll have the best of it before the crowds wade in.
Featured in Ten snorkelling beaches with reefs right off the sand · Beach