The Hoi Ha Wan Marine Park is one of the first batch of Marine Parks established in Hong Kong. It was designated on 5 July 1996. Hoi Ha Wan Marine Park is a sheltered bay located north of the Sai Kung West Country Park. It covers an area of about 260 hectares.

The seaward boundary is demarcated by linking the tips of Heung Lo Kok and Kwun Tsoi Kok through the northern end of Flat Island (Ngan Chau) and Moon Island (Mo Chau). The landward boundary follows the high water mark along the coastline.