Tunnel Beach is located 7.5 kilometres southwest of the city centre of Dunedin, New Zealand. Located just south of St Clair, Tunnel Beach has sea-carved sandstone cliffs, rock arches and caves. Beyond the beauty of the rugged sandstone cliffs, its claim to fame is the tunnel down to the beach that a local politician, John Cargill, son of Captain William Cargill, had commissioned for his family in the 1870s.
Access to the beach is via a track across private farmland, and is open year round excluding lambing season from August to October.
The track was opened in 1983, and is a popular walking track. It descends from 150 metres (490 ft) above sea level at its start a short distance off Blackhead Road, winding for some 1200 metres to the top of the tunnel, close to a natural sea arch. The tunnel descends 72 steps to the beach, and is dimly naturally lit.