Zandvlei Estuary Nature Reserve, Nature reserve in Western Cape, South Africa

Zandvlei Estuary Nature Reserve is a 300-hectare reserve in Muizenberg, near Cape Town, centred on the only working estuary on False Bay's coast. The estuary opens to the Atlantic in winter; in summer a sand bar is closed manually and breached for a few days at full moon to maintain salinity. The reserve also covers Cape Flats Dune Strandveld and Cape Wetland vegetation.

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. The reserve now covers 300 hectares and includes an Environmental Education Centre.

The reserve hosts the Imperial Yacht Club, the Peninsula Canoe Club and a SCOUTS South Africa Sea Scout base, which hold sailing and rowing regattas and an annual Kon-Tiki raft-building competition. An Environmental Education Centre serves school groups, and anglers need a standard fishing permit.

The reserve is easy to reach from Lakeside train station or by car along Main Road, making it accessible from central Cape Town. Early morning gives the best light and the most activity around the water, so it is worth arriving before mid-morning.

The estuary is one of the few along the Western Cape coast that uses a managed opening system, where a controlled breach to the sea is made once a month to regulate the water's salt levels. Without this intervention, the mix of fresh and salt water would shift rapidly, affecting the species that depend on those specific conditions.