Many-banded krait or banded sea snake?

Diving Green Island, Taiwan, I found this snake. It looks very much like a many-banded krait (Bungarus multicinctus) but since it was swimming under water and hiding under a coral rock I am not sure. Could it be a banded sea snake? The pictures I have seen look different. Any help appreciated.

Wolfram

What are often called "sea snakes"are in fact kraits, so you're on the right track.  Hard to tell which species without seeing the head, I suppose. 

This is not a Banded Sea Krait (Laticauda colubrina), which is white/silver/gray with black bands, rather than black with white banding.  I would go with your first bet, the Taiwanese Bungarus multicinctus.  As I understand it, this species of Bungarus eats fish and often inhabits brackish waters.  If you found it miles offshore -- you do not say, that would certainly be very unusual; nevertheless, based on what we see of its appearance in your photograph, it certainly looks similar to the Taiwanese Bungarus multicinctus and is definitely not Laticauda.

Take a look at Emdocephalus annulatus, Turtle Headed Sea Snake.

Thank you very much for the fast reply, this is a great community! I think Chowe is right, it looks like Emdocephalus annulatus or the related Emydocephalus ijimae. The latter is endemic in south Japan, China, and Taiwan, so that looks pretty good. I found this snake during shore dives about 100 m from the coast in 10 - 15 m depths.

Best, Wolfram