Dive & Snorkel Location
Carysfort Lighthouse Reef sits at the northern boundary of the Florida Keys National Marine Sanctuary — further out, less visited, and more alive than almost anything else on the reef system. While other operators crowd Molasses and Dry Rocks, Carysfort stays quiet.
Standing in the water at Carysfort, with a 172-year-old iron lighthouse rising above you and untouched coral stretching as far as you can see below, you understand why our crew calls this the secret gem of the upper Keys.
Two distinct reef structures — a shallow inner reef near the lighthouse starting at about 5 feet, and an outer reef that drops into deeper water with star coral ridges and swim-throughs.
Because Carysfort is further from Key Largo than most sites, few boats make the trip. Less disturbance means healthier coral and more space in the water.
Carysfort is a northern Mission: Iconic Reefs restoration site inside a Sanctuary Preservation Area — protected shallow conditions ideal for snorkel-only exploration.
What You'll See
The Carysfort Reef Lighthouse was built in 1852 — the oldest iron lighthouse in the United States. It rises 112 feet above the water and was built after decades of shipwrecks on this reef, including the HMS Carysfort in 1770.
Today the lighthouse stands decommissioned but intact. From the surface, snorkeling directly beneath it, you can look up through clear water at the red iron tower — one of the most memorable frames in Keys snorkeling.
At a Glance
Good to Know
The Schooner and Lighthouse tour and the Icons and Secrets tour both visit Carysfort Reef Lighthouse. Conditions and itinerary can vary by day — book the tour that matches your preferred sites.
The shallow inner reef starts around 5 feet deep near the lighthouse. Outer reef terrain drops gradually into deeper water with ridges and gullies.
It sits farther north than popular central stops like Molasses and Dry Rocks. Fewer operators run the longer transit — which is exactly why we go.
Tours That Visit This Site
$99 | 4.5 Hours | 3 Stops
Famous Christ of the Abyss plus two secret hidden gems most visitors never see: a historic schooner wreck and remote Carysfort Lighthouse Reef.
$80 | 3.5 Hours | 2 Stops
Northern sanctuary reefs — Carysfort Reef Lighthouse and a shallow 300ft wooden schooner wreck, on The Siren at 70% capacity.
Summer tours are filling up fast — book your trip to the John Pennekamp reefs today.
