The interplay between the formation of neutron skin and α cluster at the dilute surface of neutron-rich nuclei is one of the interesting subjects in the study of neutron-rich nuclei and nuclear clustering. A theoretical model has predicted that the growth of neutron skin will prevent the α clustering at nuclear surface. Quite recently, this theoretical perspective, the suppression of α clustering by the neutron-skin formation, was firstly confirmed experimentally in Sn isotopes as the reduction of the ( p , p α ) reaction cross section. Motivated by the novel discovery, in this work, we have investigated the relationship between the neutron-skin thickness and α clustering in C isotopes. Based on the analysis by the antisymmetrized molecular dynamics, we show that the α spectroscopic factor at nuclear exterior decreases in neutron-rich C isotopes, and the clustering suppression looks correlated with the growth of the neutron-skin thickness.