Coconut crabs live alone in underground burrows and rock crevices. They dig their own burrows in sand or loose soil. During the day, the animal stays hidden, to protect itself from predators and reduce water loss from heat. They live almost exclusively on land, and some have been found up to 6 km from the ocean.

Mating occurs near the sea. After this the female lives within 100 metres of the sea to regularly moisten herself with seawater. The young (as zoea) are spawned from the eggs into the water. The zoea takes 3-6 weeks to go through 4-5 zoea stages and form an ampbibious stage called a glaucothoe. The benthic, shrimplike glaucothoe finds a minute shell and after 3-4 weeks it migrates ashore. After about 4 weeks of living around the high tide mark, it transforms into a juvenile crab, which continues to use a gastropod shell for 1-2 years, and lives very secretively in burrows.

They are solitary and usually nocturnal, especially where human activity is frequent. They are omnivorous, commonly eating the fallen fruit of Pandanus and the Coconut Palm.