Moat Wall in the United States offers shore-accessible snorkelling along the exterior of the Fort Jefferson moat wall. This structure functions as an artificial reef, providing a distinct environment for snorkelers. Conditions are variable, with visibility typically ranging from 10 to 25 metres and mild currents. Water temperatures fluctuate between 24C and 30C throughout the year. The site is suitable for beginners and features facilities including changing rooms, toilets, and guided tours. Divers and snorkelers should remain aware of potential hazards such as boat traffic, jellyfish, lionfish, sea urchins, sharks, sharp coral, strong currents, and surf.

South Swim Beach is a shallow reef site in the United States suitable for beginner divers. Access is via a shore entry, leading to a relaxed dive with mild currents. Visibility typically ranges from 3 to 9 metres, and water temperatures remain between 24 and 30C throughout the year. Divers frequently encounter Great Barracuda, Purple Sea Fans, and various wrasses. Other species recorded include Atlantic Tarpon, Blue Tang, and Caribbean Spiny Lobster. When navigating the reef, exercise caution as the coral and rocks have sharp edges. On-site facilities include parking, showers, changing rooms, a rinse station, and a cafe.

Park Headquarters reef in the United States offers a diverse underwater environment featuring a combination of natural reef, artificial structures, and seagrass beds. The site is accessible via shore entry and sits at an average depth of 6 metres, with a range of 4 to 8 metres. Visibility typically spans 5 to 10 metres. While suitable for beginners, divers should be prepared for moderate currents and potential surf during entry. Water temperatures remain warm, ranging from 24 to 30 degrees Celsius throughout the year. On-site facilities include parking and a dive shop to support your visit.

Dry Tortugas is a remote marine site located 112 kilometres from the nearest shore, accessible only by boat. The area features a diverse topography including reef, wreck, artificial reef, and seagrass habitats. Depths range from 2 to 30 metres, with an average of 15 metres, making it suitable for beginners in the shallows and more experienced divers at depth. Visibility is generally high, ranging from 18 to 36 metres. Divers should be prepared for moderate currents and potential thermoclines. Hazards include boat traffic, jellyfish, sea urchins, and sharp coral. Guided tours are available to assist with navigation in this expansive area.

Loggerhead Reef is a shallow marine site located in the United States, offering depths between 2 and 4 metres. This site is accessible by boat and features visibility ranging from 10 to 30 metres. Divers should be prepared for a moderate current, which requires careful planning of entry points to ensure a manageable return. Water temperatures remain warm throughout the year, typically between 25 and 30 degrees Celsius, making a light wetsuit or skin suit sufficient. Due to the shallow depth and manageable conditions, the site is suitable for those new to diving, though awareness of current and positioning is essential for all visitors.

The Windjammer Wreck is a shallow artificial reef located 914 metres offshore in the United States. Resting at an average depth of 7 metres, the site is suitable for beginner divers. The wreck structure features sharp metal edges and coral growth, requiring careful navigation. Divers should be prepared for moderate currents and variable visibility, which typically ranges between 3 and 9 metres. Due to the current and potential for low visibility, staying close to the wreck as a reference point is recommended. Boat support is required for all dives at this location, with typical dive times lasting approximately 45 minutes.