A marine park is a designated park consisting of an area of sea (or lake) set aside to achieve ecological sustainability, promote marine awareness and understanding, enable marine recreational activities, and provide benefits for Indigenous peoples and coastal communities. Most marine parks are managed by national governments, and organized like 'watery' national parks, whereas marine protected areas and marine reserves are often managed by a subnational entity or non-governmental organization, such as a conservation authority.
The largest marine park used to be the Great Barrier Reef Marine Park in Australia, at 350,000 km until 2010, when the United Kingdom announced the opening of the Chagos Marine Park or Chagos Archipelago.