OverviewIsthmus Reef is located just about dead center at the entrance to Isthmus Cove on the northwest side of Catalina Island. Like most of the diving at Catalina you must use a boat to reach the dive site. The reef is a long strip that runs in an East - West direction with the eastern side coming up shallow enough to snorkel over. Besides the shallow reef area the main attraction of Isthmus Reef is the walls surrounding the reef on three of the sides. Some of the walls are stair-steps and others are drop-offs.
UnderwaterIsthmus Reef has a wide selection of animals and in good quantity too. From the thick kelp growing in the shallow reef area and working your way down the slopes, to the gorgonians and other plants and animals living on the reef in the deeper waters. There are lots of rock piles spread out over the reef, along with various size cave systems that allow for many animals, like eels, lobsters, and octopi to hide out in. You can also find horn sharks resting in the rocks and kelp, besides the numerous other fishes that enjoy swimming around Isthmus Reef. Keep your eyes open and have a good time diving!!