Koko Head is the peninsula that overlooks and creates the southwest side of Hanauma Bay. There are two craters on Koko Head, as well as telecommunications facilities. It is reached by Kalanianaole Hwy (Hwy 72), which becomes H-1 in Honolulu.
The Nature Conservancy maintains a preserve in the larger crater and conducts hikes and excursions on weekends to the preserve. Call for information.