How to Identify the Yellow-Lipped Sea Krait (Identification Guide)

Key identifying features

The yellow-lipped sea krait (Laticauda colubrina) is a semi-aquatic elapid readily told apart from other sea snakes by the combination of a strongly banded body, a flattened paddle-like tail used for swimming, and bright yellow coloring restricted to the upper lip and snout. It is one of the most commonly encountered sea kraits across the Indo-Pacific, and its distinctive markings make it one of the easier marine snakes to identify in the field.

Coloration & pattern

The body is pale bluish-gray to blue-black, crossed by a series of wide, jet-black rings that encircle the entire body from just behind the head to the tail tip. These bands are evenly spaced and do not narrow or break along the sides, distinguishing it from banded terrestrial snakes that often show incomplete rings. The head is black on top, but the snout, upper lip, and area around the mouth are a striking bright yellow, sharply contrasting with the darker head coloration. This yellow facial marking is the single most useful field mark for the species.

Head, eyes & scales

The head is small and only slightly distinct from the neck, typical of sea kraits, with a somewhat blunt, rounded snout. The eyes are small with round pupils. Scales on the body are smooth and overlapping, arranged in a pattern typical of elapids, and the belly scales are enlarged compared to many other sea snakes, an adaptation that still allows the krait to move on land, since it comes ashore to digest food, rest, and lay eggs.

Size & body shape

Adults typically reach 3.5 to 4.5 feet in length, with females noticeably larger and heavier-bodied than males. The body is cylindrical and only moderately compressed compared to fully marine sea snakes, reflecting its amphibious lifestyle. The most obvious body feature is the tail, which is flattened vertically into a broad, oar-like paddle used to propel the snake through water; this is a reliable way to distinguish any sea krait from a superficially similar banded terrestrial snake.

Range & habitat where you'll see it

This species is found throughout coastal and island waters of the Indo-Pacific, including the Philippines, Indonesia, and parts of the South Pacific such as Fiji. Unlike fully pelagic sea snakes, yellow-lipped sea kraits spend considerable time on land, and they are frequently seen basking on rocky shorelines, coral rubble, or beach vegetation near the high-tide line, as well as swimming in shallow reef flats and lagoons.

How to tell it apart from look-alikes

Other sea kraits, such as the black-banded sea krait, lack the yellow lip and instead have an entirely black or bluish head. Banded true sea snakes (family Hydrophiidae) usually lack the ability to move well on land and often have narrower heads fused more smoothly into the neck, plus they rarely bask on shore. Terrestrial banded snakes lack the paddle tail entirely and have rounder, non-flattened tails suited to land movement rather than swimming.