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Tokunoshima · Japan · Wall · Pinnacle · Pelagic & blue water

Tonbara

Giant trevally and dogtooth tuna on rock towers in open water

Tonbara is a cluster of offshore rocks off Kanami in the north of Tokunoshima, whose drop-offs rise from a seabed close to 100 m. Strong currents make it an advanced-only dive that can be made only at slack water on neap tides. Divers go for the big pelagics: giant trevally and dogtooth tuna turn up here often.

Also known as トンバラ, トンバラ岩, Tonbara Rock.

Where it is and how deep

Depth profile of Tonbara: typical dive to 30 m (to 100 ft), deepest point 100 m (328 ft) 18 m · Open Water30 m · Advanced40 m · Recreational limit30 m100 m maxtypical dive
Depths on a shared scale to 120 m (394 ft); dashed lines mark common certification limits.

27.9235° N, 128.9927° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.

The dive

The dive is timed for the slack at a neap tide, the only window when the current eases enough to get in the water. Divers work down the rocks to a maximum of 30 m, with how deep the group goes set by the current on the day. They hold on to the towers of rock and look over the edge of the drop-off into the blue, where the bottom lies close to 100 m below. Giant trevally and dogtooth tuna are the reason for the dive, and the chance of meeting them out off the edge is high.

Marine life and season

  • Trevally & jacks
  • Tuna
Month-by-month season rating for Tonbara
JanFebMarAprMayJunJulAugSepOctNovDec
GoodGoodGoodGoodFairFairPrimePrimePrimePrimeGoodGood

Season follows Tokunoshima: Reachable only in the calm months from June to about October, and then only at neap-tide slack.

Know before you go

  • Strong, changing currents run over the rocks; the site is dived only at slack water on neap tides.
  • The drop-off falls away to a seabed close to 100 m, far below the 30 m limit of the dive.

Sources

  1. Tokunoshima: Where Turtles Swim and Whales Sing — Savvy Tokyo
  2. Tonbara area guide — Redfin
  3. Tokunoshima diving tips — South West
  4. Tonbara dive point — DivePoint
  5. Tonbara Rock — Tokunoshima Town
  6. 徳之島ダイビング — Greenfield
  7. ファンダイビング — Sea Divers Navi
  8. OpenStreetMap — OpenStreetMap

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