Head and body length of P. tridactylus is 243-415 mm and tail length is from 198-325 mm. Weights average from 660-2,200 grams. The fur is straight, soft and loose. Coloration ranges from brownish to grayish with the underparts lighter and the tail is usually tipped with white. The muzzle of P. tridactylus is elongated, hence the common name of Long-nosed Potoroo. Females have four mammae within a well-developed pouch that opens forward.

Preferred habitats are dense grassland or low thick scrub. P. tridactylus forages for its main food source, fungi, by digging irregularly shaped holes. It may also take insects, grasses, roots and other types of vegetation to supplement its diet.

Nests are believed to be built during the breeding season and then only by females. Estrous cycles last 42 days and females are polyestrous, breeding twice a year. Gestation is non-delayed, usually resulting in one offspring. When the young is four days old, the mother mates again. If the first baby is lost, the new embryo will develop. If not, development will not occur for about 4.5 months. At birth the baby is 14.7 - 16.1 mm long and detaches from the nipple at about 55 days. It leaves the mother’s pouch at 130 days and sexual maturity is reached at one year of age for females.

P. tridactylus is found in SE Queensland, coastal New South Wales, NE Victoria, SE South Australia, Tasmania and King Island (Australia).