Mechanical testing of soft materials, such as polymers, elastomers and bio-materials, presents considerable challenges that do not arise when characterizing metals and ceramics. Soft elastomers, mostly silicones and acrylics, are interesting candidates as dielectric materials in electroactive polymer (EAP) actuator technology [1]. In this paper we investigated the elastic properties of poly(dimethylsiloxane)-based elastomer films using various mechanical tests. Uniaxial tensile and compression tests were performed in room conditions in order to determine the elastic modulus that showed to have similar values for both tests. In order to investigate the membrane behavior, biaxially stress tests were performed by indentation of freestanding circular films with various spherical indenter sizes at loads up to 1 N. The load–deflection measurements showed a non-linear elastic response, typically for elastomers, that depends on span length and indenter size. Also, the load-displacement measurements of indentation of flat films showed a strong non-linearity. In this case, classical Hertz solution is not valid, so other constitutive models that account for non-linear elastic contact needed to be considered.