Previously the species was known as Microhyla berdmorei. Trofimets et al. (2024)  revised the species and separated representatives from Borneo, Sumatra and Peninsular Malaysia from the nominal species M. berdmorei.

Microhyla sundaica is a small frog (max. 31.4 mm in females, males approximately. 3 mm less) of the forest floor. The coloration is made up by shades of brown. Note the conspicuous markings across the shoulder and beteen the eyes. The dorsal skin is shagreened. The first finger longer than half the length of second finger. Fingers bear well developed adhesive discs with medial groove. Discs even wider and more clearly grooved at the toe tips, resembling a pair of scale-like pads per toe.  When gently stretched forward, the tibiotarsal articulation of the hind limb reches far beyond the snout tip. Toes fully webbed. The throat and chin of males is dark-gray, beige in females. Hindlimbs with 2-3 dark cross-bars. Iris uniformly grayish-bronze. 

For its size, this species has long legs and can make impressive jumps. 

Microhyla sundaica has been reported to inhabit mostly lowland primary and secondary rainforests. But the specimen on the photo was found almost 1.000 m asl near Bario. We have never found a site where this species was abundant. Maybe we were just not at the right time at the right place or adults are very secretive and come out from their hidings under certain conditions. Trofimets et al. compiled natural history notes frodm the literature. A common theme seems to be that this species is most likely encountered at temporarily flooded, shallow forest pools with lots of leaf litter. 

Details of its reproductive biology and larvae have been described by Leong (2004) for Peninsula Malaysia populations: Tadpoles are mid water column suspension feeders. They lack keratinized mouthparts. The spiracle is medially positioned on the belly. Tadpoles are delicately build and reach a maximum total length of 23 mm.