Moon Cave is one of five known entrances on the south face of G.Benarat. 30m above the forest canopy, it is remote and well protected and from the ledge at its entrance there are stunning views, as far as the eye can see, over the green forest canopy to the west and up the Melinau Gorge to the east. The small entrance has a very strong wind blowing out, a clear indicator of extensive cave passages beyond, and the entrance series is very well decorated with fine cave formations. Huge stalactites hang down from the roof in clusters, where tiny inlets creep down through the cracks in the limestone. The floor of this series is a mixture of boulders and patches of sharp crystal-covered, compacted mud deposits. The passage here is relatively large, averaging 10m wide by 15m high, but deeper into the hillside the walls and roof move away, creating a passage of truly vast proportions. The further the cave burrows into the mountain, the larger and more spectacular the passages become.

The cave was found during the 2005 expedition, when the entrance was discovered during an attempt to reach a larger, obvious entrance in the cliff above. Subsequently exploration groups have discovered over 7km of passage and have connected Moon to two adjacent systems - Benarat Caverns, which runs broadly parallel to Moon’s main passage, and the complex maze of Cobweb Cave which is situated on the western flanks of Gunung Benarat. These two significant connections have created one cave system with over 50km of passages at many different levels inside the mountain.

Like most of Benarat Caverns, Moon Cave follows a predictable, strike orientation throughout its length. Both main passages, Benarat Mainline (Moon Cave) and Benarat Highway (Benarat Caverns) are formed in this way along bedding planes within the limestone. From Camp Five in the Melianu Gorge, these steeply dipping beds are very obvious, running diagonally across the face of the cliff. Within the mountain, passages at different levels are often connected by ramps of considerable size running up the beds.

Moon was found during an attempt to reach a large, square-shaped cave entrance high up on the Benarat cliffs. Although this is formed on a separate bed, it is highly likely that this will ultimately be connected with Moon Cave through a network of ramps and passages. Finding the connection just needs time.