Abstract The experimental and theoretical characterization on viscoelastic behavior of 1-3 piezocomposites subjected to electromechanical loading is carried out. The effective properties are measured experimentally using the resonance based measurement technique and experiments are also preformed to understand the time-dependent electromechanical behavior for various fiber volume fractions of 1-3 piezocomposites subjected to constant prestress and cyclic electric field. The experimental results show that 1-3 piezocomposites exhibit viscoelastic behavior. Hence time-dependent effective properties of 1-3 piezocomposites are evaluated using the proposed viscoelastic based numerical model (unit cell approach). The evaluated effective properties are incorporated in a finite element based 3-D micromechanical model to predict the time-dependent electromechanical response of 1-3 piezocomposites and compared with the experimental observations. The developed micromechanical model is extended to evaluate the figure of merit (FoM) for underwater and bio-medical applications subjected to constant compressive prestress under cyclic electric field. © 2015 Elsevier Ltd.