Dive Flags, Floats, and Surface Marker Buoys (SMBs)
Dive flags, floats, and SMBs signal to boaters to be on the lookout for divers or snorkelers below the waves. Dive flags are a universally-recognized symbol flown by every responsible diver.
Dive flags are flown to show boaters and everybody on top of the water, that there are divers below. The diver down flag is flown for safety.