Blue Hole

Blue Hole is an advanced dive site within Sardinia's Porto Conte Marine Protected Area near Alghero, featuring a dramatic vertical shaft that drops through the limestone bedrock to 35 meters. The circular opening at the top floods the shaft with blue light, creating the mesmerizing color effect that names the site. The shaft walls are encrusted with orange and yellow sponges, small gorgonians, and colonies of cup corals. At depth, the shaft opens into a lateral cave passage where lobsters, large conger eels, and cave-dwelling shrimp reside. Red coral specimens grow in the twilight zones between open water and full darkness. The Blue Hole connects to a network of passages within the Porto Conte cliff system, though only the main shaft is routinely dived. Perfect buoyancy control is essential to protect both the delicate formations and the diver in this confined vertical environment.