Summary. In aquatic environments, the biofouling process is assumed to initiate from the conditioning layer of absorbed organic carbon residues on wetted surfaces. Microfouling organisms attach to this conditioning layer, building up a biofilm on which further biofouling proceeds. In dolphins, biofouling reduces hydrodynamic efficiency and may negatively affect health if not managed. In this study we examined the skin surface of the pilot whale (Globicephala melas). Employing cryo-scanning electron microscopic techniques combined with various sample preparations, the skin surface displayed an average nanorough surface characterized by a pattern of nanoridge-enclosed pores. The average size (pore size appr. 0.20 µm2) of the pores was below the size of most marine biofouling organisms, and the implications to self-cleaning abilities based on reduced available space for attachment, the lack of any particular microniche for biofoulers to hide, and their challenge to the turbulent water flow and liquid-air interfaces during surfacing and jumping of the dolphin are discussed.