Endophytics fungi are found in Rhizophora apiculata mangrove. They are known to produce bioactive compounds that act as an antibacterial, which can be a solution for sustainable use without destroying existing resources. This study aims to determine the types of endophytic fungi on the species of R. apiculata as antibacterial. The method used was the isolation and identification of endophytic fungi from the species of R. apiculata and the antibacterial activity test using the Kirby Bauer method. The results obtained three types of fungi from five pure isolates, namely Aspergillus sp., Cladosporium sp., and Penicillium sp. Three genera of endophytic fungi were found to have antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa bacteria. The rate of inhibition against S. aureus and P. aeruginosa from Cladosporium sp. extract respectively were 17.45 ± 1.15 mm and 2.85 ± 0.08 mm, Aspergillus sp. was 14.61 ± 1.07 mm and 2.6 ± 0.20 mm, and Penicillium sp. was 14.11 ± 0.08 mm and 2.7 ± 0.20 mm. These three isolates showed inhibitory activity against both bacteria. However, the level of inhibition was stronger against S. aureus (gram positive) than P. aeruginosa (gram negative), especially by marine Cladosporium extract found in this study.