Scuba Diving at Osezaki

Scuba Diving at Osezaki takes place on the volcanic shore of the Osezaki peninsula in Numazu, on the western shore of Suruga Bay in Shizuoka Prefecture, one of the most popular shore-diving spots in the Izu region. Dive sites sit within a few hundred metres of the beach entry point, with black volcanic sand slopes, patches of coral, and residents such as frogfish, nudibranchs, and schooling fish that draw both macro photographers and open-water divers. The site is typically used by certified divers; most of the dive shops clustered around Osezaki's entry points ask to see a valid certification card and logbook before a dive and require a minimum certification level such as Open Water for anything beyond the shallowest sites, though some shops also run supervised introductory try-dives for uncertified visitors in shallow water. A typical half-day trip runs a two-dive session of about 3-4 hours including a surface interval, with a dive briefing beforehand covering entry and exit points, expected depth and current, hand signals, and the plan if a diver becomes separated or needs to surface early. Full scuba kit and a 5-7mm wetsuit are available to rent from the shops at Osezaki; certified divers should bring their own logbook and certification card, and an underwater camera is optional. Diving is possible year-round, but visibility and water temperature are best from July to October, while winter dives require a thicker wetsuit or drysuit for the colder water. Shore conditions can change with swell and wind direction, and dive shops will adjust or cancel dives at exposed sites when the surf is too rough for a safe shore entry.