The deep blue, circular Hanauma Bay on the south-east tip of East Honolulu was once a volcanic cone. It has become one of the most popular places to snorkel on the Oahu, with about 3,000 visitors a day coming to view its glorious reef and assortment of fish and other sea life. As Hawaii’s first Marine Life Conservation District, great care is taken to educate visitors on preserving the delicate ecosystem, and first-timers must watch a video at the Marine Education Center when they arrive. So make sure you don’t litter, or touch the sea animals or coral. You can hire snorkel gear or bring your own, then swim out off the beach to the colourful underwater world that awaits. Be aware, the nature preserve is closed every Tuesday to give the fish a chance to feed without interruption. You can catch a shuttle from Waikiki Beach or drive. Be aware that the parking lot fills up quickly. There are parking fees and a daily fee to enter the nature park.