Marine arenicolous fungi constitute a valuable resource inhabiting deteriorated ecosystems, where diversity is threatened by human-related activities. Though, information regarding their genetic diversity remains poor. Therefore, the aim of this study was to suggest inter-simple sequence repeat (ISSR) primers as an accessible tool to conduct screenings of the genetic diversity in marine fungal species, using as a model Corollospora maritima sensu lato. Our results demonstrated that ISSRs represent an efficient genotyping technique. We were able to calculate the standard summary statistics for population genetics, indicating that isolates from the Caribbean Sea and the Gulf of California harbor high levels of genetic diversity compared to isolates from other littorals.