What signal indicates a diver is in the water?

The signal that indicates a diver is in the water is a red flag with a white diagonal stripe, often referred to as a “diver down flag.” This flag serves a critical safety function on the water by alerting boaters to the presence of divers below. The red color signifies danger, while the white diagonal stripe provides a clear indicator that divers are in the area, urging vessels to maintain a safe distance to prevent accidents.

Other flags, while they may indicate various conditions or activities, do not specifically denote the presence of divers. For instance, a green flag is commonly associated with safe swimming conditions, a yellow flag often indicates caution or a hazard, and a blue flag might be used to signal other boating or swimming activities. Thus, the red flag with a white diagonal stripe is the universally recognized signal for diver awareness.