reef
intermediateboat entry

Yonaguni Monument

Yonaguni · Okinawa · Japan

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.

25 m
Max depth
good
Visibility
November–June
Best season

Marine Life

hammerhead shark
barracuda
sea turtle
manta ray
reef fish

Best Season to Dive

Highlighted months represent the ideal conditions for diving

22°C – 28°C
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Location

Yonaguni · Okinawa · Japan

Coordinates: 24.4350, 123.0100

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Dive Site Depth Profile

Visual depth progression and waypoint route for Yonaguni Monument

Max Depth:25m
Waypoints:5
0m0m5m5m10m10m15m15m20m20m25m25mSea SurfaceEntry2mReef section 115mDeepest point25mReef section 212mSafety stop5m
* Plot shows dive progression checkpoints sequentially from left to rightDiveOne Club Depth Profile v1.0

Why dive here

Terraced stone structure
Hammerhead sharks (winter)
Historical mystery
Remote island

Videos

What Is The Yonaguni Monument? Japan's Underwater Pyramid

Yonaguni Monument - Japan's Lost Atlantis

Conditions & safety

Skill levelintermediate
Entry typeboat
Max depth25 m
Currentmoderate
Visibilitygood
Best seasonNovember–June
reefboat divehistoricphotographyiconicshark

FAQ

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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