Three Sisters Cave

Meet the site

The Three Sisters is one of the most physically demanding cave dives in the Mount Gambier region, and one of the oldest documented – the cave has been known since at least 1933. It originally had three roof windows, hence the name, but today there is a single gated entrance a few metres off Glencoe Mile Hill Road near Tantanoola. Entry is through a 1 m concrete pipe followed by an 18 m vertical drop, climbed on a wire rope ladder with every person clipped to a belay.

At the bottom is a large talus mound – a cone of collapse debris, with glass fragments and other rubbish that fell through the windows over the decades – leading down into a dome chamber about 30 m in diameter. The main chamber reaches about 35 m. Beyond it the cave's notorious 'flattener', a restriction only 30-40 cm high that runs for several metres, is the reason the site is sidemount-only and graded Advanced Cave.

Rules are extensive and reflect both the vertical entry and the roadside location: helmets mandatory inside the cave, one responsible adult topside, a maximum of four divers in the water, one vehicle on the hard pan, hi-vis vests and cones, and the key collected from the Glencoe Post Office and Bistro. Wattle Range Council owns the site. The dive rewards fit, experienced Advanced Cave sidemount divers with a big, dramatic chamber and a genuinely committing restriction; for everyone else, the ladder alone should give pause. Allow a full morning for rigging and traffic management.

What you might see

Very little – occasional cave crustaceans

Location

A sidemount-only Advanced Cave site entered through a 1 m concrete pipe and an 18 m vertical drop beside Mile Hill Road near Glencoe/Tantanoola; a 30 m dome chamber to about 35 m.

Facilities nearby

None at site. Key, food and toilets at Glencoe Post Office and Bistro; fills in Mount Gambier.