Secret Bay is right besides the ferry terminal in Gilimanuk. It's almost a wasteland at first glance. There is a diving facility there run by Dive & Dive, but, if you don't dive through them, things can get rough -- no water to rinse, for example. The most important thing while diving here is to make sure you go in during high tide or you're diving blind! Vis drop down to 1m at low tide. But the critter life is phenomenal. I did a 2.5 hr night dive here since it was so good. You literally sweep your light back and forth and you'd discover new or rare things every time you look. Again, dive during high tide!!!