Okinoshima Island — Coral & Tropical Fish Near Tokyo

**Tide timing:** The sandbar is walkable 2-3 hours before and after low tide. High tide completely submerges the connection — plan around tidal charts available at Tateyama tourist info. Summer low tides (July–August) occur in early morning and late afternoon, ideal for avoiding midday heat. **Snorkeling zones:** The north side (facing the bay) has calm, shallow water ideal for beginners and families. The south side (open ocean) has stronger currents but better coral formations and larger fish. Intermediate snorkelers should explore the south rocky areas 30 minutes before low tide when visibility peaks. **Marine life calendar:** Summer (July–September) brings tropical species carried by the Kuroshio Current — clownfish, parrotfish, and occasional sea turtles. Spring (April–June) is clearest water due to plankton bloom decline. Autumn sees juvenile fish sheltering in the reef. **Conservation note:** The reef is monitored by Tateyama Marine Science Museum. Visitors are asked to avoid standing on coral (wear reef-safe shoes), use reef-safe sunscreen, and not remove shells or creatures. The fragile ecosystem faces pressure from warming water temperatures.