High-elevation ecosystems are characterized by unique environmental conditions, which establish correspondingly unique niches for microorganisms, including protosteloid amoebae – unicellular protists with key roles in organic matter decomposition and nutrient cycling. This study primarily assessed the diversity and occurrences of protosteloid amoebae on a remote mountainous range with varying elevations. Field sampling was conducted across several sites, and organic debris and litter were collected, returned to the laboratory and placed on primary isolation plates. In total, 13 species of protosteloid amoebae and protosteloid-like organisms were observed. These belong to 11 genera, with distinct species including Ceratiomyxella tahitiensis sp. complex, Echinosteliopsis oligospora, Schizoplasmodium cavostelioides, Soliformovum irregulare, and Protosteliopsis fimicola. However, community analyses revealed no significant differences compared to the lowland areas and revealed close similarities among the sampling sites. The findings of this study provide additional information on the existing microbial diversity in the mountainous ranges with a tropical semi-temperate climate, which has implications for their biogeographical patterns and distribution.