A classic boat-access outer-wall dive off the Nunukan Islands, dropping through a steep reef into a small coral cave before finishing on a sandy slope. This is a fast, current-driven site rather than a relaxed reef, so good buoyancy, tide timing, and a clear turn-pressure plan matter more than a long route. Expect blue-water passes, big-fish action, and a dive that can change character quickly with the tide and the boat briefing.