© 2015, Escuela de Ciencias del Mar. All rights reserved. The internal volume of aquaculture net pens is an important variable to fish comfort during the culture process. In this research, a module of net pens was modelled using the finite element (FE) software AquaSim®. The net pens deformation was analyzed under different current speeds (0.25, 0.50 and 0.75 m s -1) and linear weights of the sinker rings (30, 40 and 50 kg m -1). It was found that under the most severe condition, that is, the highest current speed and the lowest linear weight of the sinker ring (0.75 m s -1 and 25 kg m -1 , respectively), the volume loss with respect to initial undeformed net pen volume reached a maximum value of 53%. This occurred in the net pen firstly exposed to currents. Based on modeling results, a relationship between net pen volume loss due to the combined effects of both water current speed and linear weights of the sinker rings is proposed.