Can You Swim During Red Tide in Florida?

Red tide is one of the most common concerns for Florida beachgoers. When a bloom hits, it can cause respiratory irritation, fish kills, and beach closures. Here's what you need to know about swimming safety during red tide events.

What Is Red Tide?

Red tide is a harmful algal bloom (HAB) caused by Karenia brevis, a microscopic organism that occurs naturally in Gulf of Mexico waters. When conditions are right — warm water, nutrients, calm seas — these organisms can multiply rapidly, creating concentrations high enough to color the water brownish-red and release toxins called brevetoxins.

Red tide is not caused by pollution, though nutrient runoff can worsen blooms. It has been documented in Florida since the 1840s and occurs most frequently along the Gulf Coast, particularly from Pinellas County south to Lee County.

Health Effects of Red Tide

Brevetoxins from Karenia brevis can affect people in several ways:

• Respiratory irritation: The most common effect. Wave action breaks cells and releases toxins into the air. Symptoms include coughing, sneezing, watery eyes, and throat irritation — especially in people with asthma or other respiratory conditions.
• Skin irritation: Swimming in water with high concentrations can cause skin rashes and irritation.
• Gastrointestinal effects: Swallowing contaminated water can cause nausea and stomach discomfort.
• Shellfish poisoning: Never eat shellfish from red tide areas — filter-feeding shellfish concentrate brevetoxins.

Should You Swim During Red Tide?

When Is Red Tide Season?

Red tide can occur any time of year in Florida, but blooms are most common from August through December, with peaks typically in September and October. Blooms can last weeks to months. Some years have little to no red tide; others experience severe, prolonged events.

How to Check Red Tide Conditions

1. Check our Red Tide Tracker for current conditions along Florida's coast.
2. FWC Red Tide Status: The Florida Fish and Wildlife Conservation Commission publishes weekly updates with sampling results.
3. Use your senses: Dead fish on the beach, brownish water, and respiratory irritation (coughing, burning eyes) when near the water are signs of an active bloom.
4. Call the beach: Lifeguards and beach patrol can tell you current conditions.

Tips for Dealing with Red Tide

• Move to a different beach. Red tide can be very localized — a beach 10 miles away might be completely clear.
• Go to the Atlantic side. Red tide primarily affects the Gulf Coast. Atlantic beaches are rarely affected.
• Don't eat shellfish from affected areas. Commercial shellfish is tested and safe; recreationally harvested shellfish may not be.
• Rinse off immediately after swimming near a bloom area.
• Leave if you feel symptoms. Respiratory irritation typically stops within hours of leaving the area.

Red Tide vs. Bacteria: What's the Difference?

Red tide and bacteria are two separate water quality concerns:

• Red tide is caused by algae (Karenia brevis) and primarily affects the respiratory system. It's monitored by FWC.
• Bacteria (enterococcus) indicates fecal contamination and can cause gastrointestinal illness. It's monitored by the DOH Healthy Beaches Program.
• A beach can have good bacteria levels but still be affected by red tide, or vice versa. They are tested separately.