Moondyne Cave, Natural limestone cave in Margaret River Region, Western Australia

Moondyne Cave is a karst cave on Caves Road, 8 kilometres north of Augusta in Western Australia's South West region. It has a pothole entrance, a length of 270 metres and a vertical extent of 26 metres, with some large dry chambers.

Joseph Bolitho Johns, known as Moondyne Joe, discovered this cave system in 1881 while exploring southwestern Australia. His name remains tied to the early European exploration of this underground landscape.

The cave bears the name of Moondyne Joe, the bushranger Joseph Bolitho Johns, who found it in 1881. It opened to the public in 1911, and guided tours ran until 1959. After restoration it reopened in 1992, but it is not currently open for tours.

Moondyne Cave is not currently open for tours, so it cannot be visited inside; guided tours ended in 1959 and the cave closed again after a 1992 reopening. The entrance is a pothole reached from Caves Road, 8 km north of Augusta, and the cave drops 26 m over a length of 270 m. Viewing is limited to what the surface and entrance area allow.

Moondyne Cave is not open for tours, so the pothole entrance and its 26-metre vertical drop are seen only by cavers. The cave was reopened in 1992 after restoration, but guided visits ended again; the 270-metre length includes large dry chambers.