Dean’s Blue Hole: the 202m sinkhole in the Bahamas

It isn’t a cave and isn’t a wreck. Dean’s Blue Hole is a near-perfect vertical shaft in the seabed off Long Island, Bahamas, and at roughly 202m it’s among the deepest blue holes reachable from the surface.

The numbers

  • Max depth: about 202m, 663 feet, at the shaft bottom.
  • Water temperature: 25 to 29°C in the warm layer; a sharp thermocline drops it sharply below roughly 30m.
  • Level: advanced to expert only. The entry is a small opening; the dive is a vertical line in open blue.
  • Season: calmest conditions roughly April to September; summer brings the steadiest visibility.

What makes it a rite of passage isn’t the depth. It’s that there’s nothing to see but blue, and the discipline to turn while you still have the gas to ascend. Treat it as a bucket-list spectator site first, not a first international trip. Train, then travel.

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