Nusa Penida is the largest of 3 islands (the others being Nusa Lembongan and Nusa Ceningan). The water here is fairly cold (because of the ocean currents) but often startlingly clear, with gorgeous corals and prolific fish, with some turtle, shark (including grey reefs and silver-tips) and – Aug-Sep – Mola-Mola (the weird and wonderful Sunfish).