zip lining

Has anyone done the zip lining? If so can you tell me about it? Can you go without buying the Carnival excursion? Dot

I haven't zip lined in GT. But I know it's up by the lighthouse and to me looks a bit lame compared to ziplines in Belize, Roatan or other places. GT is essential a flat island that has a slight rise to the northern end. If you are planning on heading tot he lighthouse via a taxi, the driver may know if you can do the zip there. But usually excursion venues that have booking from cruise ships don't allow cruise passengers to use their facilities except via a ship excursion. It's one of the conditions of the contract.