The tunnel through the rock to Tunnel Beach is very narrow, steep with tiny steps. It is unlit and can be wet and slippery. This is definitely a single file tunnel. I can't imagine how long it took to cut, all to provide a family with a private beach, but am glad that they took the effort. The entrance to the tunnel can be seen on the satellite view of the Google map. A small black circle just southwest of the location pin .

Tunnel to Tunnel Beach - Dunedin visitor guide showing a virtual tour of 'Tunnel to Tunnel Beach' linked to an interactive map with local and travel information. 360° panoramas from Otago.

The narrow tunnel leading down to Tunnel Beach was carved out of the rock by workmen employed by John Cargill in the 1870s. This provided his family with private access to the beach, itself really only properly exposed at low tide. Today the beach is open to the public, but requires about an hour round trip to walk down the hill and back up again to the car park at the end of Tunnel Bridge Road. Because of this, you are relatively assured of solitude.

From Dunedin follow signs for St Clair Park on Middleton Road. This becomes Blackhead Road. About 2.5km past St Clair Park is Tunnel Beach road, an unsealed track. Follow this to the end and park. Walk down the path to Tunnel Beach from here. A round trip takes about an hour.