The fearless filmmaker reached the Mariana Trench of the Pacific Ocean, southwest of Guam, on Sunday (26Mar12).
The Titanic director is only the third person to venture to the ocean's deepest point and the only one to do so solo. He confirmed the news to his support crew waiting for him at the surface, writing, "All systems OK."
He also posted on his Twitter site, "Just arrived at the ocean's deepest pt (point). Hitting bottom never felt so good. Can't wait to share what I'm seeing w/ (with) you."
Cameron has partnered with the National Geographic Society to "conduct deep-ocean research and exploration to expand our knowledge and understanding of these largely unknown parts of the planet."
He previously landed the world record for the deepest solo dive earlier this month (Mar12) by diving five miles (8.2 kilometres) off the coast of Papua New Guinea.