On July 25, 2020, the bulk carrier MV “WAKASHIO” ran aground off the coast of the Republic of Mauritius, damaging the ship hull and causing an oil spill from August 6. This paper organizes the environmental impacts on coastal ecosystems in cases where similar accidents occurred on tropical coral reefs and mangrove ecosystems, and the points that should be considered in carrying out medium- to long-term monitoring. It first describes the characteristics of the coral reefs and mangrove forests that adjoin the site of the grounding incident, and provides an overview of the environmental impacts of oil spill incidents that have occurred in tropical coastal ecosystems in the past. It then organizes the approach to the short- to medium- and long-term monitoring in the case of the Mauritius incident or similar incidents. Finally, based on these, it provides an outlook for the medium- to long-term environmental recovery from the accident.