This bay was created when the exterior wall of a volcanic crater collapsed, opening it to the sea and thereby giving birth to O'ahu's most famous snorkeling destination. Even from the overlook, the horseshoe-shape bay is a beauty, and you can easily see the reefs through the clear aqua waters. The wide beach is a great place for sunbathing and picnics. This is a marine conservation district, and regulations prohibit feeding the fish. Visitors are required to go through the Bay's Education Center before trekking down to the Bay. The Center provides a cultural history of the area and exhibits about the importance of protecting its marine life. Check out the "Today at the Bay" exhibit for up-to-date information on daily tides, ocean safety warnings and event activities. Food concessions and equipment rentals are also on-site. Come early to get parking, as the number of visitors allowed per day is limited. Call for current conditions. Weather permitting, Hanauma Bay by Starlight events are held on Saturday, extending the opening hours to 10 PM. COST: Donation $5; parking $1; mask, snorkel, and fins rental $8; tram from parking lot down to beach $1.50.