35,800 ft. in the Mariana Trench in the Pacific. The deepest submersible was a bathyscape called the Trieste and that went to the bottom of the trench mentioned. The deepest a submarine has gone was 21,415 ft.

As has been stated by Aquatic Eagle, the Mariana Trench in the Pacific Ocean is the deepest plade in the oceans. The most accurate measurement of the deepest spot is 35,798 feet, but the Japanese probe Kaiko in 1995. Now, as far as submersibles, the deepest manned submersible was the Trieste, which explored the Challenger Deep, the deepest place in the Mariana Trench on January 23, 1960. It has never been repeated with a manned vehicle. However, this was not a submarine http://www.pbs.org/wnet/savageseas/deep-side-journey.html The first Soviet Alfa class submarine reportedly reached 1,200 meters, or 4,265 feet. http://www.wisegeek.com/what-is-the-deepest-depth-a-submarine-can-go.htm The US used to have two DSRV's (Deep Sea Rescue Vehicles) capable of reaching 5,000 feet. Though technically not a true submarine, they had their own battery operated propulsion system and could maneuver under their own power once delivered to their operating area by a mother submarine, which carried the DSRV. http://en.wikipedia.org/wiki/Deep-submergence_vehicle The NR-1, a deep diving nuclear research submarine built by Admiral Rickover in 1967, had a reported operating depth of 2,375 feet. http://www.knowledgerush.com/kr/encyclopedia/NR-1_Deep_Submergence_Craft/

The deepest part of the oceans of the world is the Challenger Deep in the Marianas Trench. It is about 11,000 meters. A bathyscaph descended to near the bottom in 1960. A unique piece Rolex "Bathyscaph" watch was strapped to the outside of it.

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