We numerically investigate the efficiency of surface-plasmon-polariton (SPP) focusing by curved chains of gold (silver) nanoparticles located on a gold (silver) surface. The employed model is based on the Green’s function formalism and the dipole approximation for field scattering by nanoparticles. The SPP focusing is considered for two cases of semicircle and parabolic chains of nanoparticles. We demonstrate that the efficiency of the SPP focusing is nonmonotonically dependent on the wavelength of an external light beam exciting the SPPs. Namely, the position of the intensity maximum at the focal point on the wavelength scale is determined by ohmic loss in the metal and scattering cross sections of individual nanoparticles in the chains. The dependence of the SPP focusing on the shape of the nanoparticle chains is also discussed.