Shimamawari offers a varied underwater terrain featuring reef, wall, and cave formations. Divers can explore depths ranging from 6 to 30 metres, with an average depth of 15 metres. The site is accessible only by boat, and divers should exercise caution regarding surf and shore break during entry and exit. Navigation requires awareness of sharp coral and rocks throughout the reef area. Current is generally mild, though visibility can vary significantly between visits, which impacts the ability to explore the deeper wall and cave sections. This site is suited for intermediate divers.

The Stella Polaris is a technical wreck dive located off Shikoku, Japan, resting at depths between 40 and 72 metres. This artificial reef structure requires advanced trimix certification and significant deep-water experience due to the extreme bottom profile and regular strong currents. Divers should plan descents around slack water to ensure safety. Visibility typically ranges from 10 to 20 metres. Water temperatures fluctuate between 17 and 24 degrees Celsius throughout the year. Surface conditions require caution due to active boat traffic. Given the depth and environmental factors, this site is strictly for experienced technical divers.

Isuzumi Reef is a boat-access site located in the Shikoku and Chugoku region of Japan. The reef structure extends from the surface to a maximum depth of 17 metres. Divers can expect mild currents throughout the site, making it suitable for beginners. Water temperatures fluctuate seasonally, ranging from 17C in March to 28C in September. As facilities at the site are unconfirmed, divers should arrive prepared with all necessary equipment, including a surface marker buoy and adequate hydration. Always verify current visibility conditions with a local operator prior to departure.

Bizen is a reef site in Japan reaching depths of 20 metres. The site features mild currents, making it suitable for beginner divers, though surface surge and swell require careful monitoring during boat entries and exits. Visibility typically ranges between 10 and 12 metres. The reef structure provides a habitat for a variety of reef fish and invertebrates. Bizen is accessible year-round and is also suitable for night diving. Boat access is required, and guided tours are available through the local dive shop to assist with navigation and locating camouflaged marine life.

Glass World is a reef site in Japan suitable for beginner divers. The reef structure extends from the surface to a maximum depth of 17 metres. Influenced by the Kuroshio Current, the site remains accessible year-round with water temperatures fluctuating between 18 and 28 degrees Celsius. Divers can expect mild currents, though visibility varies significantly depending on local conditions. Access to the site is by boat only. The reef features distinctive shikoro and white corals, providing a habitat for various reef fish and invertebrates. A slow, patient approach around the coral structures is recommended to observe the local marine life.

Sumisaki is a reef dive site in Japan suitable for beginner divers. Located 300 metres from shore and accessed by boat, the site features depths ranging from 5 to 18 metres with an average of 12 metres. Divers experience mild currents and visibility between 10 and 20 metres. The site offers facilities including changing rooms, showers, and equipment rental. Water temperatures fluctuate between 18 and 27 degrees Celsius throughout the year, requiring appropriate thermal protection during cooler months. Typical dives last approximately 45 minutes.

Ando no Hana is a muck dive site located off Shikoku, Japan. The topography consists of sediment and rubble, extending from the shallows to a maximum depth of 27 metres. The site is suitable for intermediate divers who can navigate variable visibility and mild currents while searching the substrate for small, cryptic marine life. Access is by boat, and divers should exercise caution due to surf and shore break conditions at the entry point. Water temperatures range from 18 to 27 degrees Celsius, with drysuits recommended during colder months. Divers should ensure all equipment and air requirements are met prior to departure, as facilities at the site are unconfirmed.

Nakagurumi is a shallow reef site in Japan reaching a maximum depth of 11 metres. The site features a mild current and is suitable for beginner divers looking to build confidence. Divers should be aware that visibility can be variable, and the substrate is prone to silt-out if buoyancy is not maintained. Access is exclusively by boat, requiring coordination with a skipper. As facilities are unconfirmed, divers must bring all necessary equipment on board. Water temperatures fluctuate between 18 and 28 degrees Celsius throughout the year. Divers should monitor their depth closely due to the shallow nature of the reef.