Iron Bottom Sound

The surface looks like any tropical strait — flat blue water between green islands. But forty metres below, the silhouettes of destroyers and cruisers emerge from the gloom, their gun turrets still trained on enemies that sank decades ago. Iron Bottom Sound in the Solomon Islands holds more warships per square kilometre than any body of water on Earth.

Between August 1942 and February 1943, seven major naval battles raged across this strait between Guadalcanal and Tulagi, sinking more than 50 American, Japanese, and Australian warships in six months of night fighting. The name was coined by US sailors during the campaign itself — a grim acknowledgement of how many ships were going down beneath them. Wrecks lie at depths ranging from 25 to 70 metres, covering everything from accessible recreational dives to technical wreck penetrations at the edge of sport-diving limits. Dive operators based in Honiara reach the most visited sites within 30 minutes by boat. The USS Juneau — whose loss killed the five Sullivan brothers and changed US military policy on family members serving together — was discovered by ROV at over 4,000 metres in 2018, far beyond diving reach, but shallower wrecks including patrol boats and destroyers are routinely accessible.