What sea snake is the only sea snake found in the eastern Pacific Ocean?

The yellow-bellied sea snake is the sea snake known for occurring in the eastern Pacific Ocean. Its range extends across tropical Indo-Pacific waters and reaches the Pacific coasts of Central and South America, including areas near Costa Rica and northern Peru.

This species is unusually oceanic: unlike many sea snakes that stay near reefs, coasts, or shallow continental waters, it is completely pelagic. It often drifts along oceanic fronts, floating debris, and mats of seaweed, using currents and warm water to disperse. Its flattened, paddle-like tail helps it swim at the surface.

For many years, scientists placed it in the monotypic genus Pelamis and called it Pelamis platurus. Molecular evidence later placed it within Hydrophis, producing the current scientific name Hydrophis platurus. The species is also notable because it is the only sea snake recorded from the Atlantic, although Atlantic records are considered unusual dispersal events rather than part of its normal native range. It is highly venomous, but bites are uncommon.