Colombia
A predominantly underwater national park off Cartagena covering the Rosario and San Bernardo island groups, protecting the largest coral reef formation in the continental Caribbean.
The park sits about 45 km from the Bay of Cartagena, combining the Islas del Rosario and the more southerly Islas de San Bernardo. Established in 1977 and expanded to its present 1,200 km2, it is Colombia's only underwater-focused national park, with reef depths ranging roughly from 1 to 30 m. It is a popular beginner-friendly diving area near Cartagena, featuring shipwrecks, colonial-era ruins and a barrier reef, hosting around 170 fish species and 52 coral species.