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.

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.

Hap's Reef is a prominent coral mound located 400 metres from shore in Apra Harbor. The site features a reef structure that rises to a depth of 6 metres, surrounded by mixed reef and sand flats that extend to depths of 20 metres. Divers typically experience visibility of 20 metres and mild currents. This site is accessible by boat and is suitable for beginner divers, with an average dive duration of 45 minutes. Water temperatures remain consistent throughout the year, ranging between 28C and 30C. Divers should be aware of sharp coral present at the site.

Barracuda Rock in Apra Harbor, Guam, is a diverse site featuring a reef, cavern, and tunnel system. The topography includes a mini cave and a tunnel beneath a large coral head, providing swim-throughs suitable for beginners. Depths range from the surface to 32 metres, with an average depth of 14 metres. Access is by boat only. Divers and snorkellers should be aware of potential hazards, including overhead environments, sharp coral, and mild currents. Visibility varies significantly, ranging from 9 to 45 metres. Water temperatures remain warm throughout the year, typically between 28 and 30 degrees Celsius.

Amtrak is a WWII-era vehicle wreck located in Apra Harbor, Guam. The wreck rests in a sand channel at a depth of approximately 40 feet, surrounded by a reef. This site is accessible via both boat and shore entry, making it a versatile location for divers. Water temperatures at the site are warm, ranging between 28C and 30C throughout the year. Due to its depth and location, it is a popular destination for those interested in historical wrecks and reef topography.

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.

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.

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.