The research of identification about sea snake in Tuan Island Waters in Peukan Bada, Aceh Besar District has been conducted. This study aims to determine sea snakes species in Tuan Island Waters. The research was begun from April until July 2018. The method used in this study research was Time Swim Method with four station observation.Types of sea snakes were identified based on their morphology, head shape, body and tail, color and band. The result showed that there were types of marine snakes in these waters, they are Acrochordus granulatus and Laticauda sp. The waters parameters of Tuan Island such as temperature, salinity and pH supported the life of the two snake species.