Okinawa · Japan · Wall · Cave & cavern
Horseshoe Cliff
A wall to 40 m off a 5 m reef, with a double arch at 20 m
Photo: そらみみ · CC BY-SA 4.0
The steepest drop-off in Onna Village, on the Manzamo headland, named by foreign divers for a horseshoe-shaped rock you look down on from the lip. The reef top sits around 5 m and the wall falls away at once — 40 m directly below the edge, 50 m a little further out — with a double-arched crevice at about 20 m. Two nudibranchs were first described from this shore.
Also known as Horseshoe Cliffs, ホーシュー, Hoshu.
Where it is and how deep
26.5062° N, 127.8487° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
Get in and the wall is already there. The reef top runs at about 5 m with hard coral growing over it, and looking into the gaps between heads turns up hawkfish, coral crabs and scorpionfish before you have gone anywhere. Then the ground ends. Directly below the lip the bottom is at 40 m, a short swim seaward and it is 50 m, and even in clear Okinawan water you cannot see it — the local description is of a spacewalk, and it comes with the warning that neutral buoyancy is not optional here.
Along the face is a large crevice with two openings stacked one above the other in a double arch, the lower one at about 20 m. That is the set piece of the dive, and it is cavern rather than cave work — divers run it on sidemount as well as in a single. North of it the wall carries on under a string of local names — Hoshu Kita, the Manza and Onna limestone caves, Triangle Hole — so which section you get depends on the boat and the day.
The fish come in two registers. Deep, the wall holds the animals photographers come for: Helfrich's firefish and pygmy seahorses down where the bottom time runs out fast. Higher up and out in the blue, dogtooth tuna, rainbow runners, bluefin trevally and schools of barracuda pass along the face. The shore itself is the type locality for two nudibranchs, Aegires hapsis and Phyllodesmium acanthorhinum, the second described from 3 to 4 m of water.
Marine life and season
- Pygmy seahorses
- Barracuda
- Trevally & jacks
- Tuna
- Nudibranchs
- Macro critters
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Good | Good | Prime | Prime | Prime | Good | Fair | Fair | Fair | Prime | Prime | Good |
Season follows Okinawa: Divable year-round; Mar–Jun and Oct–Nov are calmest, while Jul–Sep is typhoon season and winter northerlies close the west coast.
Know before you go
- The current can pick up here without warning; it is the point in Onna where local guides single that out.
- The wall bottoms out at 40 m below the entry and 50 m offshore, so decompression obligation builds quickly if you follow it down.
- The crevice is an overhead with two stacked exits; carry a light and treat it as cavern diving rather than a swim-through.
Photos from Horseshoe Cliff
そらみみ · CC BY-SA 4.0
そらみみ · CC BY-SA 4.0
Questions divers ask
How deep is Horseshoe in Onna, Okinawa?+
The reef top is about 5 m and the drop-off is at 40 m directly beneath the entry, reaching 50 m a short swim offshore. The local guide lists the point's working range as 30 to 50 m, which is why it is run as an experienced diver's site.
Can you shore dive Horseshoe Cliff?+
Yes. Take the road beside Manzamo, park and enter from there; the point is dived from the beach and from a boat equally. Boats come from the harbours near Manzamo or from Seragaki fishing port.
Sources
- ホーシュー — 恩納村のダイビングポイント — 沖縄ダイビングスクール ワールドダイビング (World Diving)
- 【2026年版】沖縄ダイビングスポットで絶対におすすめの26選 — 沖縄ダイビングスクール ワールドダイビング (World Diving)
- Shore & Night Diving, Okinawa — Reef Encounters
- Aegires hapsis — Wikipedia
- Phyllodesmium acanthorhinum — Wikipedia
- Nominatim search: 万座毛 — OpenStreetMap
Photo credits
- The eroded limestone arch of Cape Manzamo, the headland the dive site sits below. by そらみみ, CC BY-SA 4.0, via Wikimedia Commons
- Cape Manzamo's rock arch seen from the clifftop grass, overlooking open sea. by そらみみ, CC BY-SA 4.0, via Wikimedia Commons
- A wide view across the grassy clifftop of Cape Manzamo toward its coral-rock arch. by そらみみ, CC BY-SA 4.0, via Wikimedia Commons
More dive sites in Okinawa
Cave & cavern
A half-flooded limestone tunnel with 5–8 m of water inside
A drop-off from 5 m to 40 m outside the cave everyone queues for
Channel & pass
A maze of channels and arches running seaward from 3 m
Reef
Stair entries onto soft coral, 5 to 20 m, day and night
Wreck
A 106 m destroyer on her side at 34-46 m, sunk off Kouri in 1945
Similar dives elsewhere
Tunnels, canyons and walls down to a plateau facing open water
Sanctuary wall from 3 m to 40 m with sea fan forests
An open-top cave in the northwest wall of a limestone island
A seamount 2 km offshore, dived at slack water for pelagics