This study aims to determine the types and abundance of epiphytic diatoms, analyze abundance indices between stations, and analyze diversity, dominance, and evenness indices of epiphytic diatom species on Thalassia hemprichii seagrass leaves. This study was conducted in March 2025 in the waters of Cindakir Beach, Kabung Bay, West Sumatra, using the survey method. Based on the results of the stu…