Body subcylindrical, only slightly compressed. Rostral higher than broad; an azygous shield separating the prefrontals, sometimes absent; frontal considerably longer than its distance from the end of the snout; 1 pre- and 2 post oculars ; 7-8 supralabials, the 3rd-4th touching the eye temporals 1+2 ; five infralabials in contact with the genials, both pairs of which are usually well developed and in contact with one another, the anterior pair smaller than the posterior ; a double series of elongated scales, the inner series the larger, at the oral margin. Scales in 21-23 rows (rarely 25). Ventrals 213 to 245, about four times as long as broad. Caudals in males 37-47, females 29-35 (Smith 1943:443).
Total length: males 875 mm, females 1420 mm; tail length: males 130 mm, females 145 mm. In colour these snakes are light or dark bluish grey above, yellowish below, with black bands more or less of uniform width throughout or narrowing on the belly (some of them interrupted below). Upper lip yellow. Snout yellow, the colour extending backward on each side of the head on each side of the head above the eye as far as the temporal shields, leaving a dark bar in between. Rest of the head is black.
They are venomous but are not aggressive to divers.
Banded sea kraits are often seen in large numbers in the company of hunting parties of Giant trevally (Caranx ignobilis) and Goatfish. These snakes need to drink freshwater and regularly come onto land.
Observation and nesting
Banded sea kraits rest and nest on rocky headlands and beaches of Sabah, Borneo. They can be seen in the wild at Pulau Tiga, the tip of Borneo and Mabul island. They are, however, seen on a many other rocky headlands around Sabah that are harder to access. Occasionally they come ashore at Tanjung aru close to Kota Kinabalu. They can be seen in captivity at The Green Connection, an aquarium in Kota KInabalu. The males come ashore early in the evening and wait at the high tide line for the females. Females are much larger and many males will escort and intertwine around a single female. They are also seen on Kadavu Island in Fiji and can often be found in the shallows whilst snorkelling. A specimen identified as a banded sea krait was seen on a small island off Padre Burgos, Luzon, Philippines, in November 2010. Locals familiar with the island say the snakes are most frequently found in crevices in the rock by day and roaming the beach and nearby waters after dark. This kind of snake has been seen also in beach in island of Boracay, Philippines.
Parasites
Banded sea kraits when collected near the tip of Borneo had heavy tick infections (Clark M & S Oakley,2011)
