Coastal ecosystems are where land and water converge creating a distinct environment hosting a rich diversity of marine organisms. This study aimed to determine the zonation pattern of mangroves and the trophic relationship among the associated macrobenthos in the local coastal ecosystem of Guang-guang, City of Mati, Davao Oriental. The establishment of the study area and gathering of field data were conducted on December 2, 2017, a period of one day during low tide. There was an absence of zonation pattern on the mangal due to Rhizophora stylosa being the only mangrove species present. The marine gastropods observed on the mangal were Monilea callifera, Pomalea canaliculata, Crassostrea iredalei, Trochus pyramis, Spisula solidissima, Zeacumantus lutulentus, Cominella glandiformis,Diloma subrostrata and Haustrum scabina. On the adjacent intertidal zone, the seagrasses and macroalgae found were Enhalus acoroides, Thalassia hemprichii, Padina gymnospora, Halophila ovalis, and Halimeda sp., and the presence of the associated macrobenthos starfish, hermit crab, Philippine sand dollar, mud crab, blue mussel, marine gastropod, shrimp, brittle star, fish and jellyfish. The area had a high macrobenthic diversity with 1.34 on the Shannon-Wiener diversity index and 0.6 on Simpson’s diversity index. On the highest trophic level of the coastal ecosystem food chain are the producers including mangroves, sea grasses and algae and the lowest on the trophic level are the tertiary consumers and apex predators are birds, turtles, and larger fishes.