That purple flag isn’t decoration; it’s a coded message from the ocean, and it can change your entire day in the water. While green, yellow, and red warn us about waves and currents, purple signals something more hidden and unnerving: marine pests. Jellyfish drifting like ghosts, stingrays buried just beneath the sand, and other venomous or stinging creatures may be sharing the surf with you.

Seeing a purple flag doesn’t always mean you must stay out of the water, but it does mean you should step in with your eyes open. Talk to the lifeguards. Ask what’s been spotted, how serious the risk is, and what to do if you’re stung. Shuffle your feet in shallow water, consider rash guards or protective gear, and keep children close. Most importantly, don’t dismiss that flag. Respecting it is how a beautiful beach day stays a beautiful memory instead of becoming an emergency.