Unlike other Marin Snakes of Hydrophiinae Family, this species bear thin and slender tail like terrestrial species. However body patterns and colour always gives confusion with venomous Sea Snakes.Morphologically it looks very close to Sea Snakes (Subfamily Hydrophiinae) due to presence of dark bands on rough body and similar head. However in former tail is compressed but not "Oar-like" which is specific character of Sea Snakes. Also head and body scales of A. granulatus are very minute and hard to count but in Sea Snakes they are found in countable and definable limits.
Average length- 80cm.
Maximum length- 122cm.
Stout, moderately long body. Body surface made of very loose skin and covered with hardly countable keeled scales of very small size. Color dark grey or blackish with white or yellowish cross-bars or usually incomplete circles; broadest on side while narrow on the top. In adults markings may become indistinct.
Belly scales not distinct from adjacent dorsal scales. A ridge like keel present on midline.
Head small, scarcely broader than neck and covered with very minute scales. Nostrils and eyes on the the uppermost level of head. Eyes small with vertically elliptical pupil.
Short tail which is laterally compressed but not like true Sea Snakes (which are venomous).