Blue Hole in Apra Harbor is a natural limestone plateau featuring a vertical shaft that begins at approximately 18 metres and opens through a window at 38 metres. This site offers a varied topography including a wall, reef, drop-off, and cavern environment. Depths range from 10 to 95 metres, requiring advanced certification and deep diving experience to navigate the shaft. Visibility typically spans 10 to 40 metres, though divers must account for potential strong currents, surge, and boat traffic. Access is strictly by boat. Due to the significant depth and overhead environment, this site presents hazards including nitrogen narcosis and decompression requirements.

Finger Reef is a sloping reef located 500 metres from shore within Apra Harbor. The site features a depth range of 2 to 27 metres, with an average depth of 15 metres. Access is by boat only, and divers should be aware of moderate currents and boat traffic in the area. The topography consists of sloping coral formations. Due to the presence of sharp coral and jellyfish, appropriate exposure protection is recommended. This site is suitable for beginners and offers a typical dive duration of 45 minutes. Visibility at the site ranges from 9 to 27 metres, with water temperatures remaining between 28 and 30 degrees Celsius throughout the year.

Sharks Pit is a drift dive located in Apra Harbor, Guam, featuring a steep slope and a large haystack rock that rises from 27 metres to 5 metres. The site is notable for its collection of WWII artifacts scattered along the slope. Divers can expect depths ranging from 4 to 35 metres, with an average depth of 20 metres. Visibility is typically between 20 and 30 metres. Due to moderate currents and boat traffic, this site requires boat access. While suitable for beginners, divers should remain aware of the depth and current conditions.

Gab Gab in Tumon Bay, Guam, offers a diverse underwater environment featuring a reef, a wall, and an artificial reef. Divers can explore depths ranging from 5 to 30 metres, with an average depth of 18 metres. Access is via a shore entry, making it suitable for beginners. Conditions generally feature mild currents and visibility between 9 and 30 metres. The site is also available for night diving, with typical dives lasting 45 minutes. Facilities including parking, toilets, showers, and equipment rental are available. Species recorded around this area include Napoleon Wrasse, Emperor Angelfish, various wrasses, and Pacific Bullethead Parrotfish. Be aware of hazards such as boat traffic, entanglement, overhead environments, and sharp coral.

Gab Gab II is a large reef mound located within Apra Harbor, Guam. Situated approximately 91 metres from the shore, the site features depths ranging from 13 to 30 metres with an average of 20 metres. Divers and snorkellers can access the reef by boat or from the shore. Conditions are generally mild, with visibility between 10 and 30 metres. The site is suitable for beginners and supports night diving. Facilities available at the location include parking, toilets, showers, changing rooms, and a rinse station. Be aware of boat traffic in the area. A typical dive lasts 45 minutes.

Vecky's Reef is a marine site located within Apra Harbor, Guam. The site features a consistent depth of approximately 9 metres, though depths in the surrounding area can reach 20 metres. Access to this location is by boat only. Divers and snorkellers should be aware of moderate currents and potential boat traffic in the vicinity. Visibility at the site typically ranges between 12 and 21 metres. Water temperatures are warm throughout the year, ranging from 28C to 30C. This site is suitable for beginners, provided they are comfortable with the prevailing current conditions.

San Luis Beach in Apra Harbor, Guam, offers a combination of natural reef and artificial reef structures accessible via a shore entry. The site is suitable for beginners, with depths ranging from 6 to 33 metres and an average depth of 18 metres. Divers should anticipate mild currents and visibility typically between 6 and 10 metres. The location is well-equipped with facilities including parking, toilets, showers, changing rooms, and rinse stations. Air fills, dive shops, and boat charters are available nearby. Night diving is permitted at this location. Hazards to be aware of include jellyfish, rip currents, sharks, sharp coral, and stonefish.

Tarzan Cave in Apra Harbor, Guam, offers a diverse underwater environment featuring a combination of reef, cave, and wreck topography. Divers can explore numerous underwater boulders and various artifacts dating back to World War II. The site is suitable for intermediate divers, with depths ranging from 9 to 18 metres and an average depth of 14 metres. Visibility is high, typically between 18 and 30 metres, with mild currents. Entry to the site can be made by either boat or shore. Due to the presence of boat traffic and depth, divers should maintain appropriate safety protocols throughout their dive.