We consider 2+1 flavor Wilson Chiral Perturbation Theory including the lattice spacing contributions of O($a^{2}$). We adopt a power counting appropriate for the unquenched lattice simulations carried out by the CP-PACS/JLQCD collaboration and compute the pseudo scalar meson masses to one loop. These expression are required to perform the chiral extrapolation of the CP-PACS/JLQCD lattice data.