Dean's Blue Hole in the Bahamas is the deepest blue hole in the world; it goes down to 220 meters (721 feet) in depth. After ascending about 20 meters (66 feet), the hole widens into a cavern of 100 meters (330 feet) in diameter.

Not much of a popular dive site for scuba diving, as others of its kind, it is best known for freediving. Numerous freediving competitions have taken place here.

Dean's Blue Hole is not rich in flora and fauna, but divers may encounter some stray sharks, groupers, snappers, and turtles.  

The site has a visibility of about 15-30 meters (49-98 feet) all year round and experiences no currents or waves. The water temperature averages 24 degrees Celsius (75 degrees Fahrenheit) in the winter/spring and 31 degrees Celsius (88 degrees Fahrenheit) in the summer.