Tatsunokuchi

Tatsunokuchi is an intermediate dive site near Nagasaki on the island of Kyushu, where volcanic rock formations create a fascinating underwater landscape descending to 25 meters. The name translates to 'Dragon's Mouth,' referring to a cave-like opening in the rock face that resembles a dragon's open jaws. The volcanic geology provides diverse substrates — basalt walls, lava tube remnants, and volcanic rubble zones — each supporting different marine communities. The temperate waters host a mix of subtropical and temperate species: colorful wrasses share the reef with rockfish and sea bream, while octopuses and cuttlefish are commonly encountered. Dense kelp forests frame the site's perimeter, adding a distinctly Japanese temperate character. The site is particularly popular during autumn when visibility peaks and nudibranchs reach their greatest diversity. Tatsunokuchi offers a unique diving experience in one of Japan's historically richest regions.