French Reef is a large, relatively shallow reef located about six miles offshore of Key Largo, just north of Molasses Reef. Stretching nearly a mile along the outer reef line, it features beautiful coral formations, sandy areas, ledges, and swim-throughs.
French Reef is particularly well known for its natural swim-throughs and overhangs, including formations known as Christmas Tree Cave, Sand Bottom Cave, and Hourglass Cave.
Despite the names given to some of French Reef’s most popular dive sites, these are not true caves. They are open reef formations where sand has been washed away beneath portions of the coral spurs, creating openings that divers can swim beneath and through. Good buoyancy control is important when exploring these formations, helping divers maintain a safe distance from the surrounding coral.
The reef features a mix of sea fans, gorgonians, brain corals, star corals, and other reef-building corals. These formations provide habitat for parrotfish, damselfish, surgeonfish, moray eels, and many other tropical reef species. Nurse sharks are also regularly encountered at French Reef and may be spotted resting beneath ledges and around the larger swim-throughs.
Sail Fish Scuba is proud to be a Blue Star Dive Operator in Key Largo, supporting responsible and sustainable scuba diving practices in the Florida Keys.
Through NOAA’s Blue Star program, we help protect the Florida Keys National Marine Sanctuary by promoting reef-friendly diving, conservation, and education for our guests.
Christmas Tree Cave features French Reef's best-known swim-throughs. The passage is only about 15–20 feet long and narrow enough for divers to pass through in single file. Light from the exit remains visible from the entrance, making it easy to navigate. Good buoyancy control is essential to avoid contact with the surrounding coral.
Site Depth: 15–40 feet
Diver level: Open Water
Hourglass Cave is another popular swim-through at French Reef, named for its distinctive shape. The passage narrows before opening into a wider section, creating its characteristic hourglass formation. Natural light filters through the openings, highlighting the coral and marine life found around the site and making it a great area for underwater photography.
Pictured is a lionfish, one of the reef’s most recognizable—but invasive—creatures.
Site Depth: 20–35 feet
Diver level: Open Water
Woody’s Ledge follows a long coral ledge along French Reef, with overhangs and protected spaces that provide excellent habitat for marine life. The combination of coral structure and abundant hiding places makes Woody’s Ledge an interesting site to explore along French Reef.
Site Depth: 25–45 ft
Level: Open Water Diver
French Twist is a shallow section of French Reef known for its winding coral channels and easy swim-throughs. The site is well suited for newer divers, while still offering plenty of interesting reef formations to explore. Parrotfish, angelfish, grunts, southern stingrays, and other tropical marine life are commonly seen throughout the area.
Site Depth: 15–30 ft
Level: Open Water Diver
Turtle Ledges is a shallow dive on French Reef where coral ridges and channels create plenty of places for marine life to gather. The site lives up to its name, with green, hawksbill, and loggerhead sea turtles often seen in the area. Divers may also encounter nurse sharks, southern stingrays, moray eels, and spiny lobsters along the reef.
Site Depth: 20–30 ft
Level: Open Water Diver
Sand Bottom Cave is the largest of French Reef’s well-known swim-throughs, with a broad opening, sandy bottom, and plenty of room to explore. Schools of small reef fish and nurse sharks are often found around the formation. Its open layout makes it an approachable and interesting swim-through for Open Water divers.
Site Depth: 25–30 ft
Level: Open Water Diver
Exploring Key Largo’s Coral Formations
~7 miles southeast from Key Largo
Reef Top: 15–20 ft
Caves & Swim-Throughs: 20–45 ft
French Deep: 55–80+ ft
Green, Hawksbill & Loggerhead Turtles
Moray Eels & Goliath Grouper
Nurse & Caribbean Reef Sharks
Southern Stingrays & Eagle Rays
Barracuda, Parrotfish & Angelfish
Spiny Lobsters
French Reef is an excellent Key Largo snorkeling destination, with shallow sections of reef beginning around 15–20 feet.
From the surface, snorkelers can look down over coral formations, sandy channels, and the reef’s distinctive spur-and-groove structure while watching colorful marine life below. Sea fans, brain corals, star corals, and other gorgonians provide habitat for schools of yellowtail snapper, sergeant majors, blue tangs, parrotfish, and angelfish.
French Reef is also home to some of the larger marine life found throughout the Florida Keys. Snorkelers may spot nurse sharks resting along the reef, southern stingrays moving across sandy areas, or sea turtles swimming between coral formations.
Here at Sail Fish Scuba, we welcome both divers and snorkelers on the same boat. If you’re traveling with family or friends who prefer to snorkel, they can enjoy French Reef from the surface while you explore it below.
Scientific Name: Lepidochelys kempii
Maximum Size: About 2–2.5 ft
Longevity: At least 30 years; exact lifespan unknown
Habitat: Shallow coastal waters, particularly areas with sandy or muddy bottoms
Diet: Primarily crabs, along with other crustaceans, mollusks, fish, and jellyfish
Sightings in the Florida Keys: Rare
Behavior: Kemp’s Ridleys are the smallest sea turtles in the world and the only sea turtle species that routinely nests during the daytime. About 95% of worldwide nesting occurs in Mexico, where females may come ashore together in large synchronized nesting events known as arribadas.
Looking for a small, guided scuba diving experience in Key Largo? We keep our groups small, include an in-water guide, and are all about enjoying a great day of diving. If that’s your vibe, come explore French Reef with Sail Fish Scuba.
Discover Key Largo scuba diving with Sail Fish Scuba, a small, family-run PADI 5-Star Dive Center offering daily guided trips to the Florida Keys’ coral reefs and historic wrecks. Whether you’re trying scuba for the first time, working toward your PADI certification, or an experienced diver looking to explore more of Key Largo, our focus is on small groups, personal attention, safety, and plenty of time in the water.
Since 2012, Sail Fish Scuba has welcomed divers from around the world to experience what makes diving in Key Largo so special. Our guests often describe our crew as patient, knowledgeable, professional, and welcoming, with many saying their dives feel more like diving with friends than being part of a crowded charter. Every recreational scuba trip includes a PADI professional in the water at no additional charge, along with complimentary underwater photos and videos so you can enjoy the dive while we capture the memories.
From shallow coral reefs filled with tropical marine life to some of Key Largo’s best-known wrecks, we’re here to help you experience the Florida Keys one dive at a time.
Daily Snorkeling and Scuba Diving Charters
Morning 2-Tank Dive Trip — Departs at 8:00 AM
Afternoon 2-Tank Dive Trip — Departs at 1:00 PM
Dive trips operate daily, year-round, with the opportunity to explore multiple sites along French Reef
