Passe Boueni sud is Mayotte's sheltered southern pass, a bright lagoon-side dive with coral heads, sand patches, and a pass profile that changes with tide and current. It is the kind of site local boats choose when the sea is less cooperative elsewhere, but it still rewards careful timing because the water can move in or out. Expect healthy coral, a broad mix of reef life, and a route that suits divers who are comfortable letting a local guide choose the day and line.