Metaphrynella sundana is a common frog found in primary and secondary lowland rainforests, as well as in hilly terrain up to approximately 1050 m above sea level (asl). It is a small species (reaching up to 30 mm in snout–vent length) with tuberculate skin and considerable variation in both coloration and texture. The toe pads are expanded, allowing for effective climbing. Despite its stocky appearance, it is also capable of jumping well, although individuals we observed generally preferred walking over jumping. The finger and toe tips often have a yellow or orange tinge. Size, skin texture, general body shape, and especially the distinctive hands make this species relatively easy to identify. It is hardly confusable with any other frog.

Males call from tree holes or other suitable phytotelmata, such as bamboo internodes. Their call is a piping note emitted at regular, slow intervals. Males are capable of adjusting their calls to match the resonant frequency of the tree hole from which they are calling—presumably to maximize the reach of the call and increase attractiveness to females approaching the site for reproduction.

The tadpoles of this species are endotrophic. Although little is known about their development, it is assumed to be rapid. The tadpoles are minute, measuring only about 9 mm in total length.