Kalophrynus barioensis is known from the highland rainforests around Bario, at approximately 1100 m above sea level.

Matsui and Nishikawa (2011) described the species as small-sized, with males measuring 18–20 mm in snout–vent length (SVL) and females reaching 21 mm. The third toe is longer than the fifth. The fourth finger and fifth toe lack subarticular tubercles; the outer metatarsal tubercle is absent, and there is an indistinct gland dorsal to the arm insertion.

The dorsal coloration is orange-brown with an hourglass-shaped marking of darker brown. The skin on the back is smooth, with scattered very small tubercles. The chin and chest are dark brown, with faint cream bands running medially and laterally. The ventral side of the limbs is pinkish-gray and dotted with dark brown. A row of round tubercles runs dorsolaterally from the posterior margin of the upper eyelid to the groin, highlighted by a light dorsolateral stripe. At the groin, the species has a distinct inguinal dark spot without a white rim or white spotting. The call consists of a short, unpulsed note, with long intervals between calls. The reproductive mode remains unknown.

Kalophrynus barioensis and Kalophrynus eok both occur in the Bario Highlands; i.e., they are sympatric. Their relationship and ecologies require further investigation.