Hydrophis nigrocinctus has large mental scute that is not concealed in the mental groove. There are 1-3 maxillary teeth behind fangs and 7-9 palatine teeth. It has 27-33 scale rows around the neck and Tail with 9-11 cross-bars and terminating in a large scale. Body is olive to brown above with 40 to 60 dark, narrow bands, while the under parts are yellowish.