Indosylvirana nicobariensis is a slender, long-legged, brown frog. The snout is long and pointed. Males and females reach approximately 50 mm. 

I. nicobariensis is a common frog in open areas. It uses irrigation ponds or ditches along roads for reproduction. These water bodies can be ephemeral or permanent. Males can occur in numbers and can form loud choruses that can be heard from some distance. 

The tadpoles grow sometimes larger than 40 mm in total length. They are mostly brown in color; darkness of pigmentation can vary. Note the pattern along the edge of the tail fins.

We found tadpoles of I. nicobariensis associated with Hylarana erythraea and larvae of the two species appear similar in general shape, but can be separated by color patterns (for example iris coloration).