Not all metal detectors are suitable for underwater use. However, there are special waterproof detector coils that are designed to work underwater. These search coils have a special seal that prevents water from entering the coil and causing damage. Make sure the detector has the required water resistance for your intended use. Also note that the detector's performance underwater may be affected due to signal absorption and interference from environmental factors. Read the manufacturer's instructions carefully and follow recommended procedures to ensure the accessory is used correctly and safely underwater.