Monday, May 20, 2024

Could Dean’s Blue Hole Still Be The Deepest Blue Hole In The World?


For a while there, it looked like a blue hole in the South China Sea had edged Dean’s Blue Hole in the Bahamas as the world’s deepest blue hole.

That record — in one sense — might not be quite correct, according to champion freediver William Trubridge, organizer of the annual Vertical Blue freediving competition.

Trubridge came across some data that shows the “Dragon Hole” in China isn’t a vertical shaft but one that is shaped more like a comma.

Sansha Yongle Blue Hole
Sansha Yongle Blue Hole (Image credit:

As he wrote in a recent Facebook post:

“I just came across this graphic indicating that it is not a vertical shaft, and that the deepest point that can be measured from the surface might be less than the 203m of Dean’s.

“There are of course many deeper non-vertical holes in the world, such as some of the Yucatan cenotes and the 404m deep Hranice abyss in the Czech Republic, but the distinction of Dean’s is that you can hang a vertical line from the surface all the way to the bottom without it touching the sides. I had thought that was the case as well with this new hole in China, until I saw this graphic as part of a research study.”

For more info about the shape of China’s Dragon Hole, check out

John Liang
John Liang
John Liang is the News Editor at He first got the diving bug while in High School in Cairo, Egypt, where he earned his PADI Open Water Diver certification in the Red Sea off the Sinai Peninsula. Since then, John has dived in a volcanic lake in Guatemala, among white-tipped sharks off the Pacific Coast of Costa Rica, and other places including a pool in Las Vegas helping to break the world record for the largest underwater press conference.