Pulau Moyo's most famous attraction is this fairytale waterfall, whose cascading pools of turquoise water have entranced at least one princess (locals call it Lady Diana Waterfall because she visited in 1993). A sign in Labuhan Aji says it's 7km away, but this is a marketing ploy to get you on an ojek (100,000Rp). It's actually a relatively easy 4km hike (bring your swimsuit!).
If you go on your own, you'll need to pay a 25,000Rp 'island tax' to your hotel in advance.