Leptomantis cyanopunctatus is a medium-sized, slender tree frog of lowland forests. The species was originally described from Khao Sok National Park (ca. 200 m a.s.l.), Surat Thani Province, District Phanom, Thailand (Manthey and Steinof 1998). Today it is know from the Malay Peninsula, northern Sumatra, Sabah, eastern Sarawak, Kalimantan,  Brunei, Bunguran I., Natuna Is.

Females reach 40 mm, males are slightly smaller.

The eyes are large and a sharp ridge runs from the eye to the nostril and to the tip of the snout. The fingers and toes bear adhesive discs. The skin texture is smooth to finely granular above. 

Usually there are white spots below the eye on the upper lip. However, some populations lack that feature. Blue spots are present in the region of the groin and on the backside of the thigh, often on the ventral side of the thigh, parts of the belly and the dorsal side of the inner toes too. The coloration of the upper side is mostly in shades of brown, sometimes the back can exhibit green. Darker markings are present. The hindlimbs are baded. Throat, chest and belly are white. 

The tadpoles were described by Leo0ng (2004) from the Malay Peninsula. The tadpoles are suctorial, black in color, long-tailed, have a cup-shaped oral disk and live in streams. The ecology of the species is largely unknown. A clutch of a captured female contained 60 eggs.