Entering the ocean in the coastal town of Muizenberg, Zandvlei is the only functioning estuary on Cape Town's False Bay coast, open to the Atlantic Ocean throughout winter and in summer the mouth is manually closed by a sand bar to contain the water, and is opened monthly for a few days at full moon to maintain salinity levels and then closed again.

It is also a vital habitat for amphibians and about 20 species of reptile such as the angulate tortoise, marsh terrapin and mole snake.

Rare or interesting plants include Gladiolus angustus and Salvia aurea (syn.

[3] The estuary was neglected in the past, and suffered from farming, urban development, dredging and the introduction of alien invasive species.

The original vegetation has been partly restored through local government and volunteer efforts.