Irabu Blue Cave

Off Irabu Island's volcanic coastline, a cathedral-like sea cave channels sunlight through a narrow underwater entrance to paint the interior an otherworldly electric blue that is widely considered one of the most beautiful light effects in Japanese diving. The cave system extends 30 metres into the cliff with chambers of varying depth, and the contrast between the glowing entrance light and the dark encrusted walls creates a theatrical backdrop for the lionfish and moray eels that shelter inside. Outside the cave, the reef slopes steeply into clear open water where schools of fusiliers swirl in the current.