United States
Channel Islands National Park protects five islands off the coast of Santa Barbara and Ventura, California, with roughly half of its area lying underwater.
The park comprises five of the eight California Channel Islands, established in 1980, covering about 250,000 acres, roughly half submerged, encircled by a six-nautical-mile buffer forming the Channel Islands National Marine Sanctuary. Recreational scuba diving is a permitted activity, with the islands noted for complex sea caves and clear autumn waters. Wreck sites lie within the Anacapa State Marine Reserve. The park also holds UNESCO biosphere reserve status.