Izu Peninsula

Before the First Dive

Give the provider an accurate certification and recent-experience history, complete the medical screening and discuss any required medical review in advance. Practice with unfamiliar rental equipment and agree entry, exit, buddy separation and surface procedures. A demanding site's minimum count is only an acceptance threshold, not proof of readiness. COCOMO explicitly uses medical screening; Hammers has additional dated requirements. Sources: COCOMO Osezaki: programs and access terms; Mikomoto Hammers: October 29, 2026 notice for 2027.

Overheads, Currents and Breath-hold Activity

Stay within training and agree an open-water route where appropriate. Wreck penetration, caves and technical diving need their own qualifications and plans. Freedivers need formal safety procedures and a trained dedicated buddy; never train alone or hyperventilate. Do not combine open-water freediving with the period after scuba on the same day. Sources: PADI: scuba and freediving safe practices; DAN World: freediving safety awareness.

After Scuba

For asymptomatic divers, DAN gives minimum preflight intervals of 12 hours after a single no-decompression dive and 18 hours after multiple dives in a day or multiple dive days. Decompression dives need a substantially longer interval; obtain individual guidance. Longer intervals reduce risk but cannot eliminate it. Izu's elevated road and sightseeing options also deserve route-specific altitude planning. Avoid immediate hot bathing or a very hot shower after diving; rapid rewarming can increase decompression stress. Sources: DAN: flying after diving; DAN: hot tubs after diving.

For an urgent incident, call local emergency services first, then the diving emergency assistance line. Tell responders the location, that the patient has been diving, the symptoms and the dive timing. Provide emergency oxygen if available and administered by a trained responder, and obtain medical assessment even if symptoms improve. Do not fly or self-direct a mountain transfer with suspected decompression illness. Sources: DAN: emergency assistance; DAN World: decompression illness.

Juntendo Shizuoka Hospital in Izunokuni publishes 24-hour emergency reception and lists hyperbaric oxygen therapy. Those pages do not confirm immediate treatment capacity for recreational decompression illness, foreign-language staffing or an available chamber at the time of an incident. Emergency clinicians should choose and contact the receiving facility. No guaranteed helicopter, transfer duration or nearest operational chamber is asserted. Sources: Juntendo Shizuoka Hospital: emergency reception; Juntendo Shizuoka Hospital: clinical engineering.

Take photographs rather than marine life, shells or geological material. Maintain buoyancy and avoid touching or chasing animals. Shizuoka's current rules restrict collection of fishing-right species and prohibit recreational harvesting using scuba apparatus; they also direct visitors away from restricted zones and working fisheries infrastructure. These collection restrictions are distinct from the separate rules for access to a dive site. Sources: Shizuoka Prefecture: marine recreation and fishing rules.

Respect local swimming/diving zones, marked boat channels and facility staff. Futo warns that prohibited-area entry can stop the day's diving. At Hirizo, follow the designated swimming area and crew or lifeguard directions. Do not treat national-park or geopark branding as authorization to enter a cave, launch a boat or harvest wildlife. Sources: Futo Diving Service: shore sites; Hirizo ferry captain: beach and sea guide.