Blue Cavern

Blue Cavern is a boat-access drift dive focused on a large open rock cavern set into a steep, kelp-covered wall. The cavern is roughly 40 feet wide and extends about 50 feet into the wall with a semi-overhead ceiling open to the surface; surrounding vertical walls, ledges, overhangs and dense giant kelp create dramatic scenery. Walls and the cavern interior are encrusted with pink cup corals, gorgonians, sponges and sea stars, and divers commonly see schools of California sheephead and blacksmith, bright orange Garibaldi, California spiny lobster and occasional California sea lions. Divers typically descend a mooring line and drift along the wall to reach the cavern entrance at about 80 to 90 feet. Visibility is often very good, commonly 50 to 100 feet, and water temperatures range about 50 to 70°F (mid-50s in winter to mid-60s to low 70s in summer). Currents are typically moderate to strong so the dive is done as a drift: enter up-current, ride the current along the wall toward the cavern and expect pickup down-current. Anchoring is not permitted; mooring lines, surface-marker buoys and drift-safety gear are used. The partial overhead environment, strong drift currents and depths near 90 feet make this site recommended for advanced-certified divers with good buoyancy and navigation skills.