This species is a relatively small within the group, with adult mean SVL of 59 mm in males and 53 mm in females.

Matsui et al. (2024) established the species and gave a combination of features as diagnosis (modified here): The tibia is dorsally scattered with small, conical warts. The first finger is longer than the second, and the tip of the third finger forms a moderate-sized disk, with a width not much wider than the basal phalanx. The tip of the fourth toe swells into a small disk, slightly wider than the basal phalanx, and is broadly webbed to the disk. The head is short, the forelimb is long, the hindlimb is long, and the tibia is medium-sized. The edges of the second and third fingers have weekly movable, narrow ridges of skin. The fourth toe disk is slightly wider than the third finger disk. The inner and outer webbing of the fourth toe is fairly well excised. 

The dorsal skin is covered with networks of wrinkles originating from scattered warts and running in all directions. The dorsum is brown with a darker brown interorbital bar and spots surrounding large warts. The abdomen is cream-coloured, with brown dots scattered peripherally.

We challenge the view of Matsui et al. (2024) that Limnonectes lambirensis "is not sympatric with other species of the L. kuhlii-like fanged frogs in Borneo" because our sampling showed clearly different species from Lambir Hills National parks: some with large tibial warts (as in L. tawauensis), some with much less warts (as in L. lambirensis). Clearly more research is needed to establish reliable distribution range data of the "kuhlii"-group species. We depict a specimen with small tibial warts from Lambir NP and tentatively (pending genetic confirmation) assign it to the L. lambirensis.