Water transfer in a sheet of natural rubber is studied during the falling rate period of drying. It is shown that natural rubber remains a diphasic medium during drying and an equation to describe voluminal contraction of the internal structure is proposed. Measurements of the evolution of the water content profile in the sheet made it possible to show that a transport law using the water content gradient as the thermodynamic force of transfer is sufficient to describe water transport during drying. The coefficient of water transport is strongly governed by the water content.