Microhyla heymonsi was first reported for the island of Borneo by Quah et al. (2025). Before the species has been well-known from Taiwan, China, Vietnam, Laos, Thailand, Myanmar, Peninsular Malaysia, Singapore, and Sumatra. Quah et al. (2025) documented several specimens in the Turaran District, Sabah. It is expected that the species will rapidly expand throughout human-modified landscapes on Borneo. 

The species is realatively unique and appearance and can be identified base on several features: 

The snout is rounded, and the tympanum is not externally visible, covered by skin. Small but distinct disks are present on the tips of both fingers and toes. The first finger is shorter than the second, and the digits bear distinct subarticular tubercles. Two small metatarsal tubercles are also present. The toes are webbed at the base. Both the back (dorsum) and underside (venter) are smooth.

A dark lateral stripe runs along each side of the body, extending from the tip of the snout through the sides of the head and flanks to the groin. This stripe is sharply set off from the paler-colored back. Unlike some related species, these frogs lack dark hourglass- or “teddy bear”-shaped markings with pale edges on the back. Instead, a narrow white vertebral stripe usually runs from the snout to the vent, often flanked by small black spots along each side. The anal region, the front of the thighs, and the lower surfaces of the tarsus are black. The limbs show faint crossbars. Chest and belly are yellowish-white.