The Negros Occidental Coastal Wetlands Conservation Area (NOCWCA) is the Philippines’ 7th Ramsar Site of Wetlands of International Importance. It spans 89,607 ha comprising the municipal waters of 10 adjacent towns and municipalities. Its waters are part of the Guimaras Strait in the north and the Panay Gulf in the south. This research aimed to assess marine mammal diversity in these coastal wetlands. Marine mammal species here were documented through strandings, interview surveys, and boat surveys. Ten species of marine mammals, including the dugong (Dugong dugon), have stranded in the NOCWCA for the past ten years. Three species were encountered in the boat surveys: Indo-Pacific bottlenose dolphin (Tursiops aduncus), Long-snouted spinner dolphin (Stenella longirostris longirostris), and Irrawaddy dolphin (Orcaella brevirostris). All species were encountered in close proximity to fishing boats, indicating possible interactions. The presence of these marine mammals here highlights the importance of these areas as essential habitats.