Most people recognize the common beach flag system: green generally indicates favorable conditions, yellow means caution, and red warns of dangerous water. Double red usually means the water is closed to the public. But the less familiar purple flag has a different purpose—it can warn beachgoers about potentially hazardous marine life.

Depending on the location, a purple flag may indicate the presence of jellyfish, stingrays, or other marine animals that can sting or cause injury. It does not necessarily mean the water is filled with dangerous creatures, but it is a reminder to remain aware, especially because some marine life can be difficult to see beneath the surface.

A purple flag can also be displayed alongside another flag. For example, green and purple together may indicate generally favorable water conditions while also warning that potentially harmful marine life has been reported. Swimmers should follow lifeguard instructions, avoid touching unfamiliar animals, and take extra care if marine life is visible nearby.

Ultimately, the purple flag is a simple safety warning, not a reason to panic. The ocean is a natural ecosystem, and while most marine life is harmless, some creatures can cause problems when encountered too closely. So if you see a purple flag, pay attention to the warning and take appropriate precautions before entering the water.