Zamami Island, Japan — Stargazing Beneath the Kerama Blue Skies

Overview

Zamami Island (座間味島, Okinawa Prefecture) lies about 40 km west of Okinawa's main island, in the heart of the Kerama island chain. Designated as Kerama Islands National Park in 2014, the surrounding sea — dubbed "Kerama Blue" for its extraordinary clarity — ranks among the world's premier diving destinations.

But the island's magic doesn't end at sunset. With minimal Light pollution thanks to its remote location, the sky overhead transforms into a breathtaking tapestry of stars after dark. Spending your days underwater and your nights under the Milky Way is a luxury that few places on Earth can match.

Observing Conditions

Home to only about 600 residents, Zamami's settlement clusters around the port, leaving the rest of the island remarkably dark. Step even a short distance from the village and artificial light all but disappears — from the beaches and lookout points, you're looking at skies measuring around Bortle Class 2.

The glow of Naha city, roughly 40 km away, occasionally shows near the western horizon, but the sky directly overhead is deep and dark. The Milky Way is unmistakably visible to the naked eye. Another genuine advantage: the subtropical climate means comfortable outdoor observing is possible even in winter, something rare in Japan.

Top Observing Spots

The Kamino-hama Viewpoint on the island's western side faces away from Naha, making it the darkest location on the island. Ancient Zamami Beach (古座間味ビーチ) opens onto the southern horizon and is well suited for picking out southern constellations.

Takatuski-yama Observatory stands at the island's highest point and offers a full 360-degree view of the sky — though hiking there at night demands care underfoot.

Getting There

High-speed ferries ("Queen Zamami") run from Naha's Tomari Port in about 50 minutes; the slower ferry takes around 2 hours. Services run two to three times daily in summer (one per day for the regular ferry). Book well in advance during summer — seats fill fast.

Accommodation on the island runs mainly to guesthouses and small inns, many attached to diving shops.

Observing Tips

Zamami's subtropical humidity peaks in summer and is a real concern for camera gear — bring dew prevention measures for your lenses. Winter months (December through February) tend to bring drier air and better sky transparency.

Beach observing is a genuinely special experience: stars reflected in gentle waves, the sound of the sea all around. Just keep an eye on the tides, and be aware that Habu jellyfish (box jellyfish) appear in summer waters — watch where you step near the shoreline.