An ular poleng, a banded krait, a sacred snake here because it's black and white stripes, more like silver grey and black.
Here's a page on it. It was about four feet long, slithering along with a bunch of us locals and bule (local word for not them) watching. It's poisonous though few deaths reported. Some dogs checked it out. One kept a distance and the other's owner held it back. It went into the sea water and swam off. Wasn't too pleased to see that as that's where I'd just been, but that's not its usual haunt. It was sort of herded there.
