Poly (dimethyl siloxane) (PDMS) is a model silicon elastomer used as marine fouling-release coating, because it meets the fouling-release zone conditions of the Baier curve. However, weak mechanical properties limit its use. In this aspect, incorporation of carbon nanoparticles into PDMS is a common method for improving its mechanical properties. Since effective dispersion of nanofillers into polymer matrices is a challenge, a major aim of this study was to examine the PDMS mechanical reinforcement by developing different dispersing methods of pristine MWCNTs into PDMS matrix. SEM images of nanocomposites prepared using dispersion methods 1 and 2 revealed the formation of aggregates which subsequently affected the overall mechanical performance of the samples. Also, the effect of p-MWCNTs content and nanoparticle type [carboxyl-functionalized-MWCNTs, graphene oxide (GO)] on the mechanical properties of the nanocomposites was evaluated. Incorporation of p-MWCNTs did not alter drastically the critical surface energy value of neat PDMS, which subsequently influenced antifouling and cleaning performance of nanoreinforced coatings. To evaluate antifouling and cleaning performance of the nanocomposite coatings, seawater immersion tests were conducted. In conclusion, MWCNTs and GO increased the mechanical strength of the matrix, whereas they contributed to a small extent to the improvement in antifouling and cleaning performance of the composites.