Yellow bellied sea snake has compressed body, posteriorly more than twice the diameter of the neck. Body scales are sub-quadrangular in shape and Juxtaposed. There are 49-67 scale rows around the thickest part of the body. It has narrow head with an elongate snout. Color variable but most often distinctly bicolored, black above, yellow or brown below, the dorsal and ventral colors sharply demarcated from one another. It also has 7-8 upper labials, with 4-5 below the eye but separated from the border by a subocular.