Sombrero Reef

Entry and exit are from the dive boat. The moderate depth and generally calm conditions make this site suitable for divers of all experience levels.

Accessible only by boat, with numerous dive operators in Marathon offering regular trips to the reef. The boat ride is typically 20-30 minutes from shore.

The reef supports rich marine biodiversity. Common sightings include parrotfish, angelfish, butterflyfish, and various snapper species. Moray eels, lobsters, and nurse sharks frequently shelter in the reef structures. The healthy coral formations include impressive stands of elkhorn and staghorn coral, along with numerous species of brain, star, and finger corals.

The reef system features classic spur-and-groove formations with coral ridges separated by sand channels. Depths range from 15-50 feet, with the most vibrant coral growth at 20-35 feet. The lighthouse serves as a navigation reference, with multiple dive sites scattered around its base. The reef structure extends over a large area, allowing for multiple dives in different sections.

Parking is available at various marinas in Marathon where dive boats depart, including Marathon Marina and Key Colony Beach Marina. Most offer paid parking with day rates.

Facilities are limited to what's provided on the dive boats. Most charter operations offer basic amenities including freshwater rinse, restrooms, and refreshments.

Moderate to high, especially during peak tourist season. The extensive reef system allows divers to spread out, even when multiple boats are present. The site is popular with both divers and snorkelers.

Strong currents can develop during tide changes. Proper buoyancy control is essential to avoid damaging fragile coral structures. Fire coral is common on the reef and can cause painful stings if touched. The site is exposed to south and east winds which can occasionally create choppy surface conditions. As a protected area within the sanctuary, collecting or touching marine life is prohibited.