The National Geographic Society, which is helping sponsor the expedition, the first in 52 years to descend so deep, said he reached the bottom at 5:52 p.m. Eastern Daylight Time.
Mr. Cameron returned to the surface Sunday evening, according to Stephanie Montgomery of the National Geographic Society, The Associated Press reported. His return was a “faster-than-expected 70-minute ascent,” according to National Geographic.
After seven years of planning — done with a team in Australia and largely in secret — Mr. Cameron strode up to his sleek 24-foot-long craft, folded his frame into a steel personal capsule just 43 inches wide and plummeted through miles of icy darkness into a trough known as the Challenger Deep. Rough seas had delayed his dive about two weeks.
“Just arrived at the ocean’s deepest pt,” Mr. Cameron said in a Twitter message earlier on Sunday. “Hitting bottom never felt so good. Can’t wait to share what I’m seeing w/ you.”
Mr. Cameron’s vehicle is unique among submersibles, its vertical axis meant to speed its descent and maximize time on the bottom. His goal is to explore the dark seabed for six hours, taking pictures and extracting samples of the fauna, before returning to sunny realms. Mr. Cameron, 57, practiced yoga to train for what is likely to be about nine hours of keeping his knees bent and body largely immobile.
Five people have died in submersible accidents over the decades, and Mr. Cameron said the risks he faced were acceptable given the testing that his craft’s parts have undergone and its backup gear for such critical systems as electrical power and life support.
His dive signals the rising importance of entrepreneurs in the global race to advance science and technology. No government can send people so deep. His team includes scientists from the Scripps Institution of Oceanography, the University of Hawaii, and other organizations.
Mr. Cameron’s plunge comes a quarter-century after he began work on “The Abyss” (1989), the first of his movies to display a fascination with the deep sea.
The Challenger Deep, which extends 6.8 miles below the ocean’s surface, is the lowest point of the Mariana Trench, itself the deepest of the many seabed recesses that crisscross the globe. The only other time humans have gone there was in 1960, when the United States Navy sent down two men who stayed 20 minutes. Their craft’s landing stirred up so much ooze that the divers could see little during their stay on the bottom, and they took no pictures.
By contrast, Mr. Cameron has packed his craft with cameras and recording devices and plans to make at least two movies: a 3-D production for wide-screen theaters, and a National Geographic TV special. His aim is to film the realm’s unfamiliar life.
Advising him on his Pacific expedition is Don Walsh, a retired Navy officer who in 1960 dived into the Challenger Deep and the record books.
“I feel so fortunate,” Dr. Walsh said in an e-mail. “Dudes my age are mostly sitting in rockers passing around snapshots of grandkids and great-grandkids.”
Early this month, after Mr. Cameron took his submarine on a test plunge to a depth of five miles, he immediately e-mailed Dr. Walsh to describe the experience and his craft’s performance.
“Overall the vehicle performed like a champ,” Mr. Cameron said. “Plenty of power, and even though I lost one thruster, I still had 11 left, so the massive-redundancy approach worked.”
Time will tell how his craft handles the greater stresses of the Challenger Deep, where the waters overhead press down with a pressure of more than eight tons per square inch.
In an interview, Mr. Cameron noted that Pennsylvania State University had used a pressure chamber to test the strength of the capsule.
“You’re going into one of the most unforgiving places on earth,” he said. “It’s not like you can call up AAA to come get you.”
