Hanauma Bay is a sheltered cove at the southeastern-most corner of Oahu, Hawai'i near Koko Head. There one finds some of the most spectacular snorkling and scuba diving in Oahu. The bay was created when the ocean broke through the wall of a volcanic crater located at the Oahu shore. The result is an area protected from the ocean with a variety of subhabitats. The inner bay, about 10 ft deep, is protected by a wall of rocks and is home to a coral reef; exotic tropical fish of all shapes, sizes, and colors; and even sea turtles. Further out is an area called the "Witches' Brew," a deeper cove (about 70ft depth) which supports strong currents and invites larger sea life including sharks. Diving here is for experts only, who must avoid the "Molokai Express" lest they leave the Oahu vicinity prematurely.

The Hanauma area is a protected wildlife preserve, so feeding the fish isn't just a bad idea, it's against the rules. Admission to the beach area comes with a small fee ($5 or so) and snorkel equipment is available for rental ($15 or so). The beach is sandy and quite large, so it is a fine place to spend the whole day; however one should arrive no later than 10am to the best snorkeling experience before all the honeymooners arrive. As usual for Oahu, Hanauma Bay is accesible by transportation.

Thanks to Frommer's travel guide for the tip, the honeymooner joke, and additional information.