Mangroves play an important role in the dynamics of the marine ecosystem. This descriptive study determined diversity of mangrove species of Calatagan Mangrove Forest Conservation Park- a Marine Protected Area located at the community of Quilitisan and of a mangrove rehabilitation area located at the community of Balibago, Calatagan, Batangas. A total of 8 quadrats measuring 10m x 10m were laid along the low intertidal zone and mid- intertidal zones of the study sites. Data on abundance, frequency and density parameters were gathered from these quadrats. There were 9 species of mangroves found in the mangrove conservation park while there were 7 species found in the rehabilitation area. The species that are common to the two study sites include A. marina, R. stylosa R. mucronata, R. apiculata, S. alba, and S. caseolaris, The species that are distinct in the community of Quilitisan include A. corniculatum, C. tagal and C. decandra. The mangrove species B. cylindrica was sampled only in the community of Balibago. The mangroves in Quilitisan have average GBH of 21.69 cm; average height of 3.89 m; average crown of 2. 16m; and average DBH of 6.90cm. The mangroves in Balibago have average GBH of 23 cm;average height of 5.62 m; average crown of 1. 76m; and average DBH of 6.90cm. The mangrove forest in Quilitisan, though with higher species richness, is found to have a relatively lower diversity index of 1.05 than that of Balibago which is 1.21 using Shannon-Weiner Diversity Index.