We went snorkeling in the Dry Tortugas in September of 2021.
We took the ferry from Key West (the Yankee Freedom) out to Fort Jefferson and it was a comfortable ride with a friendly and professional staff. We only took a day trip (I don’t mind sweating during the day, but I want my creature comforts at night) and it was definitely worth it, although it terms of underwater sea life, John Pennekamp Coral Reef State Park in Key Largo, Florida offers a better experience.
Construction of the fort began after the War of 1812 in order to defend the US southern coastline and more specifically, one of the most strategic deep-water anchorages in North America, which afforded the US an advance post for ships patrolling the Gulf of Mexico and the Straits of Florida.
The lighthouse @ Fort Jefferson was added in 1825 to provide warning to sailors about the dangers of reefs and shoals surrounding the Dry Tortugas.
I’m a bit of a history buff and the site provides informative placards in the different areas, like the gun emplacements and soldier’s barracks. It was interesting to be able to climb through the remnants and have context to the history. You can also download a self-guided tour, which I loved because I’m not really into groups or tours. Overall, worth the trip at least once if you’re interested in US history. If you’re only interested in snorkeling, there’re lots of better locations in South Florida, including right off the beach in Fort Zachary Taylor Historic State Park in Key West, where you can also get a dose of US Civil War history.
Musings of a Dragon 