No, Barbados is not under sea level. Unlike some neighboring islands in the Caribbean that are volcanic and mountainous, Barbados is a relatively flat "coral limestone" island, but its entire landmass sits above the ocean surface. The average elevation across the island is quite low, with its highest point, Mount Hillaby, reaching only 340 meters (1,115 feet) above sea level. However, because much of the coastline is low-lying—particularly the popular West and South coasts—it is highly vulnerable to rising sea levels caused by climate change. Geologically, Barbados is actually "rising" due to tectonic activity, which has created the island's famous "terraces" of ancient coral reefs stacked on top of one another. So, while you won't find deep basins below the waterline like in parts of the Netherlands or New Orleans, the island is very much "low-profile" and pays close attention to coastal management and sea-level monitoring to protect its world-class beaches.