The dive took place in the Pacific Ocean's Mariana Trench, China's Xinhua News Agency reported.
The dive started at 7 a.m. local time in heavy rain and the three aquanauts -- Ye Cong, Liu Kaizhou and Yang Bo -- reached the record depth of 7,015 meters below the surface at about 11 a.m.
While deep below sea level, the trio sent greetings to the three Chinese astronauts expected to conduct a manual docking of the Shenzhou-9 spacecraft with the orbiting Tiangong-1 lab module.
"We wish for a great success of the manual docking and brilliant achievements in China's manned space and manned deep-sea dive causes," the aquanauts said.
In three previous three dives conducted from June 15 to Friday, the submersible had reached a maximum depth of 22,800 feet, Xinhua said. All three dives beat the country's previous record, set when the submersible went to 7,000 feet last July.