Yonaguni Monument (Underwater Ruins, Iseki Point)
Giant terraced rock formations, natural or man-made depending on who you ask, with schooling hammerheads in winter.
- Advanced
- Rock formations
Advanced≤30 m
Ugan
Dive site in Okinawa & Yonaguni, Japan
Huge rocks rising from 40 m off Zamami, facing open ocean where dogtooth tuna, amberjack and sometimes mantas pass.
- Max depth
- 40 m
- Level
- Advanced
- Best months
- Apr–May
- Entry
- By boat
- Current
- Strong
The dive
A rock formations dive from a boat. Known for manta rays and tuna.
Who it's for
Advanced≤30 mSource: en.marinediving.com
Recommended minimum: Advanced (PADI Advanced Open Water, N2).
- CurrentCurrent can be strong; you need good air management and buoyancy.
- Strong current: dive with a local guide and carry a surface marker buoy.
- The site goes deeper than 30 m: Advanced divers stay above 30 m.
Conditions
- Dive type
- Rock formations
- Environment
- Open water
- Water
- Sea water
What you might see
- Manta rays
- Tuna
Season in Okinawa & Yonaguni
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
- Best
- Good
- Possible
- Closed
- Not documented yet
Best months: Apr–May.
Source: visitokinawajapan.comWhere is Okinawa & Yonaguni?
The point shows the Okinawa & Yonaguni area, not the exact dive site.
More dives in Okinawa & Yonaguni
Artificial reef
down to 7 m
Amuro Fish Reef
Shallow 7 m artificial reefs off Amuro Island overgrown with finger coral and busy with fish.
- Open Water
Reef
down to 15 m
Gorilla Chop
Beach dive in northern Okinawa named after a shoreline rock shaped like a gorilla's karate chop, with plenty of coral and colourful fish.
- Open Water
Drift
down to 30 m
Irizaki Point
Blue-water drift off Yonaguni's western tip watching hammerheads in open ocean, with dogtooth tuna, barracuda and bigeye trevally.
- Advanced
- Whale sharks
Reef
down to 15 m
Manta City Point
Shallow manta spot near Kabira Bay, around 10 m deep, where even beginners can watch manta rays glide past.
- Advanced
- Manta rays
Pinnacle
down to 40 m
Shimosone
Open-sea reef south of the Keramas with rocks rising from a 30 m seabed and 30-50 m visibility; summer-only.
- Experienced
- Sharks
About this page
Values marked “Estimated” come from our original catalogue and are being checked against published sources one by one. Sourced values link to where they come from. Conditions change with the season, the weather and the tide: confirm with a local dive centre before you dive.
Photo credits
- Stepped rock terraces of the Yonaguni Monument, Melkov, CC0, via Wikimedia Commons
