MARCO ISLAND, Fla. — If you’ve seen the headlines this summer about a “giant seaweed blob” swallowing Florida beaches, you’d be forgiven for bracing yourself before a walk on South Beach or Tigertail. The good news: so far, you probably don’t need to.
2026 is shaping up to be one of the largest sargassum years on record. The University of South Florida’s Optical Oceanography Lab, which tracks the floating brown algae by satellite, reported that the Gulf region alone reached roughly 5.0 million metric tons of sargassum in June — nearly double the historical record for that month. Researchers are calling it at least the second-largest bloom ever measured, trailing only 2025.
But almost all of that seaweed is landing on the wrong side of the state to bother Marco Island. The brunt of this year’s bloom is hitting Florida’s Atlantic coast and the Florida Keys — Miami Beach, Fort Lauderdale, Palm Beach, the Treasure Coast and the ocean-facing side of the Keys are all running moderate to heavy, with beaches occasionally closed to swimming and crews raking daily just to keep up. Southwest Florida’s Gulf-facing beaches, including Naples, Marco Island, Sanibel and Siesta Key, have stayed “clear to light” all season, according to beach-monitoring services and USF’s tracking data — and that’s held true even in a record year.
Why the Gulf side gets a pass
The explanation comes down to ocean currents. Sargassum drifts west out of the Caribbean and gets pulled into the Gulf of Mexico by the Loop Current — but that same current typically sweeps the seaweed back out and around the bottom of the Florida peninsula, feeding it into the Gulf Stream, which then carries it up the Atlantic side of the state. Marco Island and the rest of the Gulf coast largely sit outside that loop, so the massive quantities of sargassum piling up in the Atlantic and the Keys mostly bypass Southwest Florida’s beaches entirely. Occasional, inconsistent patches can still drift ashore near Naples and Fort Myers, but nothing resembling the walls of seaweed reported farther east and south this year.
There’s a second piece of good news for anyone weighing a beach day: red tide, the algae bloom that more typically troubles the Gulf Coast, has been quiet this summer as well, according to Florida beach-monitoring reports.
What to know if a patch does show up
Sargassum isn’t dangerous in the water, but decaying seaweed on the sand releases hydrogen sulfide — the source of the “rotten egg” smell — which can irritate breathing for sensitive individuals. Tiny hitchhikers in the seaweed, including jellyfish larvae sometimes called “sea lice,” can also cause an itchy skin rash on contact. Preliminary research out of Florida Atlantic University found the bacteria Vibrio attached to microplastics tangled in offshore sargassum mats, but scientists caution that finding is based on samples far out at sea, hasn’t been documented in the seaweed that reaches shore, and shouldn’t be treated as an established health risk from a day at the beach.
Florida law also prohibits removing sargassum from the water before it reaches shore, since it serves as habitat and food for fish including mahi-mahi and other species prized by anglers. Once it’s on the sand, it’s fair game to clean up — Marco Island’s volunteer beach cleanups, most recently held in May and June at South Beach, focus on litter and debris rather than organic material, since seaweed removal at scale is typically handled separately by the city rather than by hand.
For now, the forecast favors beachgoers: barring a shift in wind or current patterns, Marco Island’s Gulf-side shoreline is expected to stay among the clearer stretches of Florida coastline through the rest of sargassum season, which typically runs into the fall.
Handy finds for island living, boating and beach days — updated by our editors