The Chūgoku region offers interesting diving options on the Sea of Japan side, including Shimane Prefecture’s volcanic Oki Islands, that are attached to the UNESCO Global Geopark and famous for their landscapes and impressive cliffs, clear blue waters and underwater topography.
Mishima Island, 45km away from Chūgoku’s Sea of Japan coast, offers dynamic diving conditions, strong currents and schooling pelagics, and there are also many diving options along the coast of Tottori Prefecture.
At the western tip of the Chugoku area, Yamaguchi Prefecture gives access to both the Sea of Japan and the Seto Inland Sea, a unique marine environment that offers a great variety of endemic species.
MAIN DIVING AREAS MENTIONED
Sea of Japan Coast
- Oki Islands (Shimane Prefecture)
- Mishima island (Yamaguchi Prefecture)
- Tottori Prefecture dive sites
- Murotsu (Yamaguchi Prefecture)
Seto inland Sea Coast
- Suō-Ōshima islands (Yamaguchi Prefecture)
- Hashira island (Yamaguchi Prefecture)
- Futaoi island (Yamaguchi Prefecture)
- Ōmi Island (Ehime Prefecture)
DIVING HIGHLIGHTS AND ICONIC MARINE LIFE
The Oki islands are the remnants of an ancient volcano’s caldera, and offer really interesting topography, including Japan’s highest sea cliffs on land, as well as underwater rocky pinnacles, arches and caves, and also leafy green seaweed bottoms, that offer shelter to smaller marine life, such as seahorses.
SCHOOLING FISH, PELAGICS AND PREDATORS
Schooling pelagics, including yellowtail and Japanese amberjack (Seriola quinqueradiata) are commonly seen on the Sea of Japan sites, both in the Oki islands or in Tottori dive sites in the summer months.
Yamaguchi Prefecture’s Mishima island, opening up to the Sea of Japan, can only be dived between July and September because of sea conditions.
When it is possible to dive theere, the island offers good visibility, strong currents and dynamic conditions, and high chances of seeing schooling pelagics such as skipjack tuna (Katsuwonus pelamis), mackerels, other types of tunas and barracudas
Hashira-jima, an island in southern Hiroshima Bay of the Seto Inland Sea, offers the chance to dive on a sunken battleship of the Japanese Navy, the Mutsu, a 224 metres long and 34 metres wide wreck sitting at a depth of 40 to 10 metres.
The Mutsu sank in June 1943, after one of her aft magazines accidentally detonated while she was at anchor.
Futaoi Island, also in Yamaguchi Prefecture, offers the chance to dive two purposely sunk wrecks, the Myoko Maru sitting at 24m, and the Rokuren Maru at 27m, which serve as healthy artificial reefs for the Kannon Strait’s marine life.
MACRO AND RENOWNED NIGHT DIVES
Good macro diving, especially on sites said to have nutrient-rich waters like Murotsu on the Seto Inland Sea, which also offers chance to see deep-water critters and plankton on Ōmi Island’s famous night dives.
It is possible to see colonies of Alveopora japonica coral, a small zooxanthellate scleractinian coral species that occurs in shallow, non-reef habitats, in the area particularly in the Suō-Ōshima island chain on the Seto Inland Sea, (Yamaguchi Prefecture).
This coral is both endangered and rare, and only found in the north-western Pacific area including Taiwan, Korea’s Jeju Island and parts of Japan.
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