Descend below the surface and discover Milford Sound’s unique underwater environment. Available exclusively to Southern Discoveries customers. There are very few places on the planet like Milford Sound’s underwater environment. Here, a phenomenon known as ‘deep-water emergence’ occurs where freshwater meets seawater and species which normally live at great depths survive in much shallower environments. Black Coral is known as a deep-sea coral, however, here in Milford Sound it is found just 10 metres below the surface. For an in-depth exploration of this incredible environment, add a visit to New Zealand’s only floating underwater observatory to your cruise in Milford Sound. Please note that our Discover More Cruises are currently unavailable. Our Nature Cruises are operating as normal. One-hour guided experience - included in all Discover More cruise departures. Located in Harrison Cove, accessible only by boat. Descend 10 metres (64 steps) beneath the water to gaze at coral, fish and anemones. Discover rare black coral. Learn about the history, ecology and geology of Milford Sound as well as conservation and tourism in the area. The only cruise departure including the underwater observatory is the Discover More Cruise. Southern Discoveries Ltd wishes to notify our customers about the natural risks and hazards prevalent in Milford Sound, the remote location where our operations are situated.