Abstract. 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.Keywords: Acrochordus granulatus, Laticauda, identification, sea snakes, Pulau Tuan. Abstrak. Telah dilakukan penelitian identifikasi ular laut di Perairan Pulau Tuan Kecamatan Peukan Bada Kabupaten Aceh Besar. Penelitian ini bertujuan mengetahui spesies ular laut di Perairan Pulau Tuan. Pelaksanaanya berlangsung pada bulan April-Juli 2018. Metode yang digunakan dalam penelitian ini adalah Metode Time Swim dengan empat stasiun pengamatan. Jenis ular laut diidentifikasi berdasarkan morfologinya, bentuk kepala, badan dan ekor, warna dan corak/bands. Hasil penelitian menunjukkan terdapat dua jenis ular laut pada perairan tersebut, yaitu Acrochordus granulatus dan Laticauda sp. Secara keseluruhan parameter perairan Pulau Tuan seperti suhu, salinitas dan pH tergolong sesuai untuk kehidupan dua spesies ular tersebut.Kata Kunci: Acrochordus granulatus, Laticauda, identifikasi, ular laut, Pulau Tuan.