The submersible, aboard its support ship, traveled to the South China Sea and the Pacific Ocean for scientific research and to explore the seabed, China's state-run news agency Xinhua reported.
Officials said for the first time, scientists will be on board for deep-sea dives.
The Jiaolong is expected to arrive at its destination in the South China Sea on Friday.
Among its tasks, the submersible will conduct research on the sea's currents, marine life and environment in the South China Sea, officials said. In the Pacific, it will study natural resources.
The mission is expected to last 110 days.
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