Solitary Islands Marine Park (SIMP) is a marine park in New South Wales State waters, Australia. It adjoins the Solitary Islands Marine Reserve and was declared under the Marine Parks Act 1997 (NSW) in January 1998. Prior to this it was declared a marine reserve in 1991. The Park was one of the first declared in NSW and stretches along the northern NSW coast, from Muttonbird Island, Coffs Harbour, to Plover Island near Sandon River, 75 kilometres to the north. It includes coastal estuaries and lakes and extends from the mean high water mark, to three nautical miles out to sea, covering an area of around 72,000 hectares. There are five main islands in the Park, North Solitary Island, North West Solitary Island, South West Solitary Island, South Solitary Island and Split Solitary Island, as well as other significant outcrops such as Muttonbird Island and submerged reefs.