Dive sites in Guam

The USS Apogon is an intact submarine and penetration is technically possible through several openings, but it is strongly discouraged without proper wreck penetration certification and equipment. The interior is extremely confined with silty conditions that can reduce visibility to zero within seconds. Most Guam dive operators will take Advanced Open Water divers to the exterior of the wreck and allow a look through open hatches but not full interior penetration. For serious exploration inside, a cavern or wreck penetration specialty and redundant air supply are essential.

The conning tower starts at around 18 metres and the deck sits at approximately 24 metres, with the keel resting on sandy bottom at about 30 metres. The depth makes this an advanced dive and most operators require Advanced Open Water certification or equivalent. Strong swimmers with good buoyancy control and at least 30 logged dives may be taken by some operators, but beginners are typically directed to shallower sites in Apra Harbor. Air consumption is a consideration at these depths as the submarine deserves at least 30 minutes of bottom time to appreciate fully.

Yes, the two wrecks lie approximately 50 metres apart on the sandy bottom of Apra Harbor and most dive guides plan the dive to visit both. A typical profile starts on the Apogon, explores the submarine for 15 to 20 minutes, then crosses the sand to the bow section of the Tokai Maru, a Japanese freighter sunk during the American liberation of Guam in 1944. The total bottom time at 24 to 30 metres means air management is important, and divers on standard 80-cubic-foot tanks may need to abbreviate the second wreck if they are heavy breathers.