Sargassum

Question

Is there much Sargassum in the Dry Tortugas now? How is the visibility around the moat now? and is it safe to swim in?

Answer

Good question. The short answer is: yes, there *can* be some sargassum in the Dry Tortugas area — but it’s usually not as bad as on some mainland beaches, and visibility & swimming conditions depend a lot on wind, currents, and recent weather.

Here’s a detailed breakdown based on available data (as of 2025) and what visitors are reporting — plus what to watch out for and how “safe” things are.

Sargassum Conditions Around Dry Tortugas

According to the University of South Florida’s Sargassum outlook for 2025, there is more sargassum overall in the Gulf of America and western Caribbean than average.
That said, whether *sargassum actually shows up in a particular spot (like around Dry Tortugas)* depends heavily on local winds and ocean currents — so even if there’s a bloom offshore, it may or may not wash into the park in large patches.
The Florida Wildlife Commission notes that sargassum is more likely during spring and summer, and can be “transported into the Keys … along the southeast coast.”
Park-visitor reports (e.g., on TripAdvisor) suggest variability: one recent commenter noted there was “a fair amount of seagrass on the beach, but not huge piles like Key West.”

Visibility & Swimming Around the Moat / Snorkel Zones

Per the National Park Service, swimming *in the moat* itself is *prohibited*.
There *are* good snorkeling areas along the moat wall (outside the moat) and other underwater habitats; the water tends to host a variety of marine life like squid, hogfish, even nurse sharks.
Because sargassum is floating seaweed, if there are scattered clumps nearby, they might slightly reduce underwater visibility, depending on how dense they are and how close they are to where you're snorkeling. Visitor comments confirm that visibility “depends on the wind and … weather.”

Safety Considerations

Swimming and snorkeling in Dry Tortugas is “at your own risk” — there are no lifeguards.
Even without sargassum, reef and marine life are present — coral, sea urchins, jellyfish — so it’s important to be cautious.
If there *is* sargassum in the water, avoid touching large seaweed mats: small organisms living in sargassum can irritate the skin.

Bottom Line

Yes, there can be some sargassum in the Dry Tortugas, particularly in summer, but it’s unlikely to completely clog the swimming or snorkeling zones every day. Visibility may be mildly affected at times, depending on conditions, but many visitors still report very good snorkeling and marine life sightings.

Swimming around the moat wall *is allowed* (just not inside the moat itself), and as long as you’re careful, you should be fine. Keep an eye on local weather and water conditions, and check with park staff when you arrive — they can give you the most up-to-date advice about sargassum that day.