The deepest submarine dive ever recorded was achieved by the Fendouzhe, a Chinese-built submersible, which reached a depth of 10,929 meters (35,853 feet) in the Challenger Deep on November 10, 2020. This dive surpassed the previous record set by the Deepsea Challenger, piloted by James Cameron in 2012, which reached 10,911 meters (35,768 feet). The Fendouzhe's verified depth makes it the current record holder for the deepest crewed dive.

The Trieste, a Swiss-built bathyscaphe, was the first to reach the Challenger Deep in 1960. Initially reported to have reached 11,034 meters (36,201 feet), subsequent analysis and modern sonar mapping suggest this figure may have been an overestimate. The more widely accepted depth for the Trieste's dive is around 10,916 meters (35,814 feet). The Trieste's historic dive marked the first time humans reached the lowest point on Earth and demonstrated the capability of human-made vessels to withstand extreme pressures.

The Challenger Deep, located in the Mariana Trench, is the deepest known point in the ocean. Exploring this region provides valuable insights into the geology, marine biology, and environmental conditions of the deepest parts of the ocean. The Fendouzhe's dive represents a significant milestone in deep-sea exploration and highlights the advancements in deep-sea technology.