The maximum operating depth of an underwater drone can vary depending on the specific model and manufacturer. Most commercial underwater drones are designed for shallow-water operation and can reach depths of up to 100 meters (330 feet). However, there are some specialized underwater drones that can go much deeper.
There are several commercial underwater drones with a depth rating of around 150 meters (500 feet) which is considered as a deep-sea model and it's specially designed for this purpose. Some of the examples include the Saab Seaeye Panther XT Plus and the SubC Imaging NEMO .
On the other hand, there are also specialized ROVs used for deep sea exploration or scientific research, that can reach depths up to 6000 meters (19,685 feet) and those are often operated by research institutions or oil companies. Examples of these ROVs include the Deep Discoverer (D2) operated by the National Oceanic and Atmospheric Administration (NOAA) and the Hercules ROV operated by Shell.
It is important to note that with increasing depth, the pressure on the ROVs/drone increases and the cost, difficulty, and risk of operations increase as well. The deeper the depth, the more specialized the equipment and the technical expertise required for operation.
When it comes to choosing an underwater drone, it is essential to consider your intended use and the maximum depth at which you plan to operate. Make sure to select a drone that is rated for the depths you plan to reach.