﻿AbstractCladosporiumspecies are cosmopolitan fungi, characterized by olivaceous or dark colonies with coronate conidiogenous loci and conidial hila with a central convex dome surrounded by a raised periclinal rim.Cladosporiumspecies have also been discovered in marine environments. Although many studies have been performed on the application of marine originatedCladosporiumspecies, taxonomic studies on these species are scarce. We isolatedCladosporiumspecies from three under-studied habitats (sediment, seawater, and seaweed) in two districts including an intertidal zone in the Republic of Korea and the open sea in the Western Pacific Ocean. Based on multigenetic marker analyses (for the internal transcribed spacer, actin, and translation elongation factor 1), we identified fourteen species, of which five were found to represent new species. These five species wereC.lagenariiformesp. nov.,C.maltirimosumsp. nov.,C.marinumsp. nov.in theC.cladosporioidesspecies complex,C.snafimbriatumsp. nov.in theC.herbarumspecies complex, andC.marinisedimentumsp. nov.in theC.sphaerospermumspecies complex. Morphological characteristics of the new species and aspects of differences with the already known species are described herein together with molecular data.