Yonaguni Monument
Overview
The Yonaguni Monument is a mysterious underwater structure off Japan's westernmost island — terraced steps, right angles, and flat surfaces at 5-25 meters that some believe are ruins of an ancient civilization. Whether natural or man-made, the site is visually stunning. Hammerhead sharks visit in winter (December-March), adding excitement to the enigma.
Marine life
Dive profile
DEPTH PROFILE
DEPTH PROGRESSION & WAYPOINTS: Yonaguni Monument
Location
Frequently asked questions
Is the monument man-made?
Debated — some geologists say it's natural sandstone erosion, others argue the precise terraces and right angles indicate human construction 10,000+ years ago.
When can I see hammerheads?
December to March — Yonaguni is one of the best places in Japan for hammerhead shark encounters.
How do I get there?
Fly to Yonaguni from Naha (Okinawa) or Ishigaki. Japan's westernmost island, just 110 km from Taiwan.
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Data Provenance
This profile is compiled from 3 operator submissions and 142 community logs. Key facts (depth, entry) are verified against official hydrographic charts.