The maximum depth detection under water is 10 feet, however, just like hunting on dry land there are many factors that will determine its ability to detect objects. This includes size, conductivity, and magnetic properties of the object. You must also consider environmental conditions, how far the object is underground, and sensitivity settings on the metal detector.
While this is model is rated as for surface exploration with an expected depth range of 2-5”, many users have received signals on objects 10-12” and more. Larger objects may be detected even deeper.