The reef encloses a lagoon of 24,000 square kilometres (9,300 sq mi), which has an average depth of 25 metres (82 ft).

The Boulari passage, which leads to Nouméa, the capital and chief port of New Caledonia, is marked by the Amédée lighthouse.

In 2008, the barrier reef and its enclosing lagoon was inscribed on the UNESCO World Heritage List for its outstanding beauty, its unique geography as a reef entirely encircling Grande Terre, and its exceptional marine diversity (in particular its coral diversity).

[5] In 2008, an assessment of northwest near-shore reefs concluded that many would be dead within years, and at best decades, if present trends relating to mining sediment and silt run-off continued.

[6] In January 2002, the French government proposed listing New Caledonia's reefs as a UNESCO World Heritage Site.