These marine crustaceans are easy to identify by the white and brown stripes on their walking legs. Overall, their bodies are greenish to dark brown, and protected by a hard exoskeleton. Their abdomen, protected by a softer exoskeleton, is curved, allowing the crabs to fit into the shape of the mollusk shells they reside in. They also have a pair of eyes, mounted on eyestalks, and gills that allow them to breathe underwater. In addition to walking legs, these crabs also have two claw legs, which are used to pass food into the crab’s mouth.

Their bodies are about 1 ¼ inches long (or about 3.1 centimeters). With their legs included, they can reach about 3 inches long (7.5 centimeters).

They are found in a wide variety of coastal habitats, including bays, mangrove swamps, sandy beaches, mud flats, intertidal and other shoreline areas. They are tolerant of brackish water and more saline ocean water, and in both temperate and tropical climate zones.

Populations of this crustacean can be found all along the Atlantic Coast, ranging from the U.S. state of Virginia down to Brazil. 

When they outgrow their shells and need a new one, they will cooperate with other individuals to get a better fit, tapping on each others' shells and waiting for the current shell resident to move out. They have been observed in gatherings made up of dozens of shell-seeking individuals, testing out discarded shells and waiting for hours at a time until they find their "goldilocks" fit. Sometimes these gatherings turn into mad dashes for a new discarded shell, with the fastest crab getting the shell (but only if it fits right.)

Adults are scavengers, feeding on whatever detritus they can find. This includes sea grasses and plants, dead animals, and other bits of organic matter. They mostly search for food along the bottom of the ocean, but they are also quite capable of foraging on land.

Little is known about the sleep habits of striped-leg hermit crabs.

Striped hermit crabs are fairly social crustaceans, and share territory with other crabs with few issues.

When ready to mate, the male will tap lightly on the shell of the female. Following copulation, the female lays a mass of eggs called a sponge, which she carries around on her abdomen. These sponges can include between 1,000 and 30,000 individual eggs, each of which is about half a millimeter long. A female can produce these egg clutches several times over the course of a breeding season.

After a few weeks, the eggs hatch into a larval stage, forming tiny planktonic organisms that transition into several more developmental stages—four swimming larval stages and one post-larval stage called a glaucothoe—before metamorphosizing on the ocean floor and finally becoming hermit crabs.

These crustaceans are not considered threatened, and are abundant in many parts of their range. Some local populations are at risk due to habitat loss, ecosystem degradation and the effects of climate change.