Why must land crabs return to water when their larvae hatch?

Land crabs must return to the water to release their eggs because their larvae require an aquatic environment to survive and develop.12

While adult land crabs are adapted to terrestrial life, they have not achieved complete independence from water for their reproductive cycle. When the eggs are ready to hatch, the female migrates to the sea to expel them into the water. Once released, the larvae hatch as microscopic, swimming organisms that feed on small organisms in the water. This aquatic stage is essential for their early development before they eventually undergo metamorphosis and transition to a terrestrial existence.2341