Endemic to Christmas Island, the Red Crabs can be found throughout the island preferring shaded areas. Active during the day, their main diet consists mainly of fallen leaves, fruits, flowers and seedlings. They prefer fresh green leaves but will eat any fallen leaves. They are not solely vegetarian and if given the opportunity they will feed on any other dead organic matter, including dead crabs, birds, snails and even human refuse.

Although most common in the moist environment of the rainforest, Red Crabs live in a variety of habitats including coastal shore terraces, and even domestic gardens. Tall rainforest on deeper soils has the highest crab density. They dig burrows in almost every square metre of available soil or live in deep crevices in rock outcrops. For most of the year, a crab will settle in one place, living in their burrow.

The Red Crabs are a keystone species on the island, acknowledged as a major determinant of the island forest structure. The Red Crabs of Christmas Island are famous for their spectacular annual breeding migration.