Scuba divers or snorkelers must display a diver-down flag that marks their diving area. Vessels should remain at least 100 feet away from the flag.
Two types of flags are used to indicate diving activity.
Scuba divers and snorkelers should not place a flag in an area already occupied by other boaters or where their diving operation will impede the normal flow of waterway traffic. Divers also should follow all of the water safety rules themselves.