Zamami Island in Okinawa, Japan — Kerma Blue Seas by Day, Star-Filled Skies by Night
Overview
Zamami Island sits about 40 kilometers west of Okinawa's main island within the Kerama Islands. Designated as Kerama Islands National Park in 2014, it's world-renowned for its transparent "Kerama Blue" waters—a premier diving destination.
Yet Zamami's charm extends beyond the sea. Remote-island conditions mean exceptionally dark night skies. Days of ocean exploration give way to nights under a full canopy of stars—a luxury island experience.
Observation Environment
Zamami is home to roughly 600 people, with settlements clustered near the port. Moving away from the village brings minimal artificial light. Beaches and observation decks offer access to dark skies. Bortle Class 2 darkness is achievable.
About 40 kilometers from Naha, Okinawa's main-island light glows slightly near the western horizon. However, overhead remains sufficiently dark for clear Milky Way visibility. The subtropical climate means comfortable outdoor observation even in winter—a major advantage. Summer and winter both work, though conditions differ.
Recommended Viewing Spots
Kami-no-Hama Observatory on the island's west side faces away from Naha, yielding the darkest skies. Kosa Zamami Beach opens toward the southern horizon, ideal for observing southern constellations.
Takatsukiyama Observatory, the island's highest point, offers 360-degree views. Nighttime hiking requires careful footing.
Access
Naha Port's high-speed ferry "Queen Zamami" reaches the island in about 50 minutes; the regular ferry "Zamami" takes about 120 minutes. High-speed service runs 2–3 times daily; regular ferries run once daily. Summer fills up fast—book early.
Island lodging centers on guesthouses and pensions, many with attached diving shops.
Stargazing Tips
Zamami's subtropical climate brings high summer humidity. Camera and lens dew control is essential. Winter (December–February) brings lower humidity and improved atmospheric transparency.
Beachside observation combines starlight with wave sounds—unforgettable. Watch tides carefully. Summer brings jellyfish risk; watch your footing near water.