Ilhéu do Boi is a rocky-islet dive off Janela, with a sheltered south-side start and a return that tracks the shoreline back toward the entry. The route is simple to follow but still demanding, because it reaches deep water and asks divers to stay close to the rocks while keeping the open-water side in view. Plan it as an advanced dive with good buoyancy and route discipline rather than a casual reef hop. The payoff is a hard-and-soft coral slope with a busy mix of parrotfish, scorpionfish, trumpetfish, moray eels, nudibranchs, and tuna.