Ryuodo

★★★☆☆ (8)

Ryuoh-do Cave on Sado Island’s Ogi Peninsula is a large sea cave nicknamed the “Blue Cave” for its clear waters and glowing blue light. Popular for diving and sea kayaking, it hosts sea slugs, seahorses, and more, offering a magical experience for beginners to intermediate divers.

Ryuoh-do Cave offers nudibranchs, seahorses, manta rays, small crustaceans, and seasonal migratory fish—perfect for close-up marine life observation.

Dive Activity

Dive Centers Catering This Dive Site

SSI Asia - Japan, SSI Service Center Japan

SSI Asia - Japan, SSI Service Center Japan

東京都文京区関口1-44-10-3F, 1120014 Bunkyo-ku, Tokyo - Japan

Dive Sites Nearby

Mares
Jabune <span class="text-color-primary text-sm"> (★4.0)</span>

Jabune (★4.0)

Jabu-ne, on Kamikomoto-jima Island in Shimoda, Shizuoka, is an advanced site with strong currents and dynamic terrain. Famous for summer–fall hammerhead sightings, it’s one of Japan’s top shark spots. Migratory and resident fish form large schools, delivering a thrilling, high-energy dive experience.
Diving Lounge aqua QUEST, 1700002 Toshima-ku,
Kamene <span class="text-color-primary text-sm"> (★4.1)</span>

Kamene (★4.1)

This dive site, situated at the southernmost tip of Mikomoto Island, is renowned as the prime location for encountering hammerhead sharks and white-tip reef sharks. It stands out as the foremost spot for such encounters.
Diving Lounge aqua QUEST, 1700002 Toshima-ku,
A Point <span class="text-color-primary text-sm"> (★4.2)</span>

A Point (★4.2)

During early summer, hammerhead sharks gather in large schools at this location, circling repeatedly in a captivating manner. Divers can enjoy extended observation periods as the sharks navigate around roots or rest on rocks.
Diving Lounge aqua QUEST, 1700002 Toshima-ku,
Kadone <span class="text-color-primary text-sm"> (★4.0)</span>

Kadone (★4.0)

Situated offshore Enokuchi and Mitsu-ne on Kamikomoto Island, this site is highly affected by tides. The depth of the reef ranges from 22 to 25 meters, peaking at 19 meters towards the end before descending sharply to 45 meters. Due to significant tidal influence, it’s considered a challenging dive, particularly for beginners.
Diving Lounge aqua QUEST, 1700002 Toshima-ku,
Enokuchi <span class="text-color-primary text-sm"> (★4.2)</span>

Enokuchi (★4.2)

This is the “standard“ dive site on Mikomoto Island. There is a large root called “Kadone“ in the west direction, and the basic diving style is to wait for the root and then surface on the spot. Average depth: around 20m
Diving Lounge aqua QUEST, 1700002 Toshima-ku,
Mitsune <span class="text-color-primary text-sm"> (★4.0)</span>

Mitsune (★4.0)

The point, situated on the north side of Mikomoto Island, experiences the influence of both low and high tides. Notably, the three roots exhibit symmetry, with the west side being flat and gradually deep, while the east side features clustered roots.
SSI Service Center Japan, 101-0051 Chiyoda-ku
Budaine <span class="text-color-primary text-sm"> (★4.3)</span>

Budaine (★4.3)

There are a number of diving spots around Kamikimoto Island, an uninhabited island off the coast of Shimoda. It is a 20-minute boat ride from the harbor to the dive site. It is a popular spot for hammerhead sharks to appear from summer to autumn when the Kuroshio Current approaches the Izu Peninsula.
Diving Lounge aqua QUEST, 1700002 Toshima-ku,
Toujima <span class="text-color-primary text-sm"> (★3.9)</span>

Toujima (★3.9)

Nakagi is located in the southernmost in the Izu Peninsula. This area benefits from Black Stream and shows various scenes underwater as the seasons change. The scenery created by nature over the centuries will attract divers both of land and underwater.
Mares, Janez Kranjc
Shobusawa Beach <span class="text-color-primary text-sm"> (★4.4)</span>

Shobusawa Beach (★4.4)

Shobuzawa in Kawazu-cho, Shizuoka, lies on Izu’s east coast. Formed by volcanic activity, it offers lava formations, reefs, and sand. Accessible by beach, it suits all levels and is popular with macro divers year-round for its clear water and rich marine life. Well-equipped facilities ensure comfort.
SSI Service Center Japan, 101-0051 Chiyoda-ku
Kumomi Ushitsuki Rock <span class="text-color-primary text-sm"> (★4.2)</span>

Kumomi Ushitsuki Rock (★4.2)

This is the most popular cave diving spot in Izu. There are many caves and covern between and around two large rocks called Ushitsukiiwa in front of the harbor.
Mares, Janez Kranjc
Inatori Port <span class="text-color-primary text-sm"> (★4.3)</span>

Inatori Port (★4.3)

Inatori in Higashi Izu faces south, offering stable sea conditions year-round despite narai winds. Shizuma Beach features 700m of gorota and white sand, ideal for all levels. Underwater guide ropes and buoys make it perfect for easy navigation and self-diving.
Mares, Janez Kranjc
Dougashima <span class="text-color-primary text-sm"> (★4.2)</span>

Dougashima (★4.2)

Dogashima Island in Nishi-Izu, Shizuoka, offers complex underwater terrain and rich marine life. Highlights include boat launches from the “Tenmado-do Cave” and “Saku-ne” with undersea hot springs. Suitable for all levels, it showcases the ocean’s changing beauty across the seasons.
SSI Service Center Japan, 101-0051 Chiyoda-ku
Futou <span class="text-color-primary text-sm"> (★4.2)</span>

Futou (★4.2)

Futou is the scenic point of Nishi-Izu. This site can be reach via beach entry or boat entry. There is a small area where you can go night diving all year round. There are caves, caverns, and arches as you progress through the shallow beach sand to the rocky terrain.
SSI Service Center Japan, 101-0051 Chiyoda-ku
Tago <span class="text-color-primary text-sm"> (★4.1)</span>

Tago (★4.1)

There are six boat points in the open sea and four in the bay at Tago. There is also one beach. At the point in the bay, there is a clump of Green Turtle Coral that looks like Okinawa, and much tropical small fish can be seen around it.
Mares, Janez Kranjc
Hokkawa Kajikaki <span class="text-color-primary text-sm"> (★4.2)</span>

Hokkawa Kajikaki (★4.2)

Kitagawa Kajikaki in Higashi Izu, Shizuoka, is a boat dive just 5 minutes from the harbor. With depths of 12–24m (avg. 14–16m), it suits all levels. Colorful soft corals, large schools of horse mackerel, Japanese horn sharks, and wrasse feeding scenes make it a vibrant, exciting site.
Scubapro, Stephen Frink
Arari <span class="text-color-primary text-sm"> (★4.2)</span>

Arari (★4.2)

This dive site boasts dynamic topography, featuring a large offshore root known as the West Root and the Horse Mackerel Root. It’s conveniently located just 5 minutes from the harbor, making it suitable even for those who are not particularly comfortable with boat rides. One of the most spectacular highlights here is the presence of stingrays, especially during early summer. In the peak season, the encounter rate with stingrays can approach 100%, and you may even witness a group of them instead of just one or two. As autumn arrives, the visibility improves, and the already dynamic topography becomes even more fascinating. You can observe kampachi and sunfish circling around, as well as the famous “school of large, motionless snappers“ in the offshore roots. Many divers who frequent this site express their amazement, saying, “I can’t believe I’m in Izu.“
SSI Service Center Japan, 101-0051 Chiyoda-ku
Koganezaki <span class="text-color-primary text-sm"> (★4.3)</span>

Koganezaki (★4.3)

Located in Koganezaki Park, you can enjoy various flowers depending on the season, and entry/exit is very easy to do due to the ramps and handrails. When you enter, you’ll see a wide range of gorotas up to a few meters deep, and beyond that, you’ll see an entire surface of the sand.
SSI Service Center Japan, 101-0051 Chiyoda-ku
Izu Oceanic Park <span class="text-color-primary text-sm"> (★3.8)</span>

Izu Oceanic Park (★3.8)

Izu Oceanic Park is the most popular dive site in Higashi-Izu. The facilities are good and there is a pool. In the summer, the area is crowded with beachgoers and ordinary people who use the pool.
SSI Service Center Japan, 101-0051 Chiyoda-ku
Futo Yokobama <span class="text-color-primary text-sm"> (★4.2)</span>

Futo Yokobama (★4.2)

A popular spot representing East Izu, close to the IOP. There are two main beach points and a lot of boat diving. There are ramps and handrails on the beach for easy entry/exit. The sea conditions are often calm and can be enjoyed by beginners.
Scubapro, Stephen Frink
Toi Beach <span class="text-color-primary text-sm"> (★4.2)</span>

Toi Beach (★4.2)

Doi in Izu City, Shizuoka, is a top West Izu dive spot with calm beaches and diverse boat sites. It offers year-round night and wreck diving, soft coral colonies, and rich marine life, making it ideal for both beginners and advanced divers seeking variety and adventure.
Aqualung
Kawana <span class="text-color-primary text-sm"> (★3.9)</span>

Kawana (★3.9)

Kawana in Ito City, Shizuoka, offers calm waters and varied topography. With easy-entry beach dives ideal for beginners and boat dives for experienced divers, it’s rich in marine life year-round. Sea turtles are frequently spotted, making it a popular and rewarding dive site.
ITA DIVING CENTER, 4103401 Numazu
Ita <span class="text-color-primary text-sm"> (★4.3)</span>

Ita (★4.3)

Ida in Numazu City, Shizuoka, is a top beach dive site in Nishi Izu, famed for its clear “Ida Blue“ waters. Its gentle rocky slope suits all levels, with rich marine life and good tidal flow. Ideal for both macro and wide-angle photography, it’s a favorite among divers year-round.
Aqualung
Usami Kagone <span class="text-color-primary text-sm"> (★2.5)</span>

Usami Kagone (★2.5)

Kagone in Usami, Shizuoka, is a beginner-friendly boat dive site where white sand contrasts beautifully with the blue sea. At 18m, the sandy bottom teems with macro life, including Datura goby symbiosis, nudibranchs, and crustaceans. Green turtles and sharks like catsharks and cirripedes can be seen year-round.
Mares
Usami Manbo Point <span class="text-color-primary text-sm"> (★3.6)</span>

Usami Manbo Point (★3.6)

Mambo Point (Mambo Ne) in Usami, is a boat dive site just 5 minutes offshore. With a max depth of 25m, it features a rocky reef rich in purple spiny dogtooth sharks and vibrant soft corals.
Mares, Janez Kranjc
Usami Beach <span class="text-color-primary text-sm"> (★3.5)</span>

Usami Beach (★3.5)

Located on the Usami Coast of Ito City, it is a good dive site for beginners and training due to its stable sea conditions and easy beach entry. The maximum depth is about 14 meters. The diving site has a variety of environments, including sand, and artificial reefs such as clay pipes and railroad tracks.