Benten Island

This dive area off Onagawa on the Sanriku coast features waters influenced by the meeting of the Oyashio and Kuroshio currents, bringing both cold and warm conditions to the site. The seascape includes fixed fishing nets and aquaculture structures such as oyster and sea-squirt shelves. A highlight is a distinctive wall of ascidians. The site is known for sightings of danglerfish year-round, with spawning observed, and for its variety of northern nudibranchs.