Japan’s underwater world is as varied as its landscape above the surface — from the subtropical coral reefs of Okinawa to the kelp forests of Hokkaido and the eel grass beds of the Seto Inland Sea. Snorkelling and underwater photography require minimal investment to access, and several of Japan’s best sites are reachable by public transport.
Okinawa: Coral Reef Snorkelling
The Kerama Islands — Zamami, Tokashiki, and Aka — sit 30-40 kilometres west of Naha and hold some of Asia’s most intact coral reefs, with visibility exceeding 30 metres on calm days. Day trips by high-speed ferry from Tomari Port are possible; overnight stays at minshuku on the islands give access to early-morning snorkelling before day-trip crowds arrive. Ishigaki and Iriomote in the Yaeyama Islands offer more remote alternatives — Kabira Bay’s glass-bottom boats and the manta ray aggregation sites off Ishigaki are particularly notable. Water temperature stays above 24°C from May through November.
Izu Peninsula and Seven Islands
The Izu Peninsula south of Tokyo and the Izu Seven Islands chain (Oshima, Niijima, Miyake, Hachijo) offer accessible Pacific Ocean snorkelling within two to three hours of the capital. Dogashima’s sea caves on the Izu Peninsula are accessible by glass-bottom boat or snorkel at low tide. Hachijojima’s clear blue-green water has earned it the nickname “Oriental Hawaii” — hammerhead sharks aggregate offshore in summer, visible to experienced divers and occasionally snorkellers at depth.
Underwater Photography Tips
Entry-level waterproof cameras (Sony RX0 II, Olympus TG-7, GoPro Hero series) cover most snorkelling photography needs at 3-5 metres depth. A red filter corrects the blue colour cast in shallow tropical water. Early morning (7-9 AM) provides the flattest sea surface and best light penetration. At Okinawa sites, subjects range from sea turtles (Zamami is famous for close encounters) to nudibranchs, mantis shrimp, and clownfish in their anemones. Buoyancy control is critical near coral — never touch or stand on reef.
Hokkaido: Cold Water Diving
Shiretoko Peninsula’s cold Okhotsk Sea holds outstanding marine life — sea eagles fishing from the surface, Steller sea lions, and in winter, drift ice visible from the water’s edge. Shiretoko’s marine environment is UNESCO-listed partly for the productivity of its cold-nutrient-rich waters. Full drysuits are required for winter diving here; summer snorkelling in sheltered coves is manageable in a 5mm wetsuit. Hokkaido’s Shakotan Peninsula offers granite sea stacks and giant kelp forests accessible to recreational divers and snorkellers.
Practical Planning
Snorkel rental is widely available at Okinawa resort beaches (500-1,000 yen per session). Tour operators offering guided snorkel trips with equipment are common at Kerama, Ishigaki, and Miyakojima — worth booking for first-timers unfamiliar with currents. Marine Protected Areas around Iriomote require guides for certain zones. Marine sting season (box jellyfish, in summer at Okinawa) is managed with protective full-suit swimwear and net enclosures at main beaches. For broader diving coverage, see the scuba diving and snorkelling guide.