Cornwallis South Reef

Cornwallis South Reef is a coral atoll in the South China Sea off Vietnam's coast. The structure features a central lagoon surrounded by coral formations that submerge during high tide periods.

The reef formed through natural coral deposition over millennia and became a disputed location during modern geopolitical debates over sea territories. Vietnam filed a declaration with the UN in 2009 clarifying that its continental shelf does not extend to this location.

The reef represents a critical point in maritime traditions, where multiple nations assert territorial claims based on historical navigation patterns.

The reef is accessible only with special permits and maritime expertise, as international regulations control navigation in this area. Visitors should be aware that waters around the structure are strictly regulated and thorough planning is needed before any trip.

Between 2014 and 2015, channels were carved through dredging to create maritime access into the reef's lagoon. These modifications altered the natural structure and served strategic purposes in the contested waters.