Dayak fruit bats are the smallest of Dyacopterus species and are considered small to medium in size for a fruit bat. Fully mature Dayak fruit bats weigh 85 to 95 g. Their dorsal side has short dark fur that is brown-grey in colour. Their ventral side is often lighter in colour. Their wing membrane attaches to their second toe and their tail is small. They also have large eyes. Dayak fruit bats have a broad rostrum and a deep jaw. They have a dental formula of 2.1.1.2 on the dorsal side and 2.1.2.3 on the ventral jaw. Dayak fruit bats have very large cheek teeth specialized for eating fruit, although they are not as large as those of other species of Dyacopterus. The size of their teeth suggests that Dayak fruit bats eat large hard fruits. There is no sexual dimorphism in this species. Male Dayak fruit bats have enlarged mammary glands that can produce small amounts of milk.