Secret Bay is the more poetic name given by Bali’s diving community to Gilimanuk Bay, adjacent to where the ferries to and from Java dock. It is about 20mins by road from Labuan Lalang/ Menjangan and located in West Bali National Park. The bay is about 2km wide, very shallow (3-12M), contains two small islands, and has some areas of mangrove. Being the only bay off the narrow Bali Strait, where currents can reach 7knots, means that Gilimanuk acts as a catch tank (a big underwater nursery!) for many larval fish. A reef lying just outside the mouth of the bay creates a channel through which these waters are swept; this is what makes Gilimanuk an extremely interesting dive site.
These strong tidal currents mean that the fish and invertebrates are extremely healthy, colourful and well-fed (also that the water is colder than generally found in Bali, around 25C). Entering the bay, as these macro critters do, from the channel, the bottom is fine black and grey volcanic sand. The channel contains no coral although the sides are scattered with bommies full of angelfish, butterflyfish, schools of razorfish and tiny reef fish that include cardinalfish and multitudes of damselfish. Secret Bay is muck-diving (ie: diving with a mud bottom) in shallow water with no water movement. Therefore, too much fin movement and/or less than perfect buoyancy control will stir up the bottom, leaving you with low visibility in that area.
The best time to dive is on the incoming tide or around high tide, it doesn’t matter if it’s early or late in the day, as the bay will have filled with clear water from the Bali Strait. At this time, visibility can be 30M+ although there’s a fair amount of rubbish floating around. Gilimanuk Bay contains many rare macro-photography subjects that include nudibranches, gobies, crustaceans, dragonets, abundant seahorse/pipefish, juvenile Batavia batfish, large areas of long-spined sea urchins with clingfish, and many, many other organisms. At other sites it’s difficult to see juveniles as they hide to avoid predators. However, as the bay is shallow there are very few large fish, therefore juveniles have very little to fear, to hide from. Night-diving at Secret Bay is a unique experience! Cephalopods of all shapes and sizes, crustaceans wandering in search of dinner, other weird and wonderful creatures.