This dive site is in a large bay with a width of around 2 km. It is actually called Gilimanuk, but was given the nickname of Secret Bay by the diving community when it was first dived. This site is well known for being am amazing nursery dive site. The bottom is made up of black sand, which can create low visibility and although there is not very much coral at this site, there is a still a large amount of marine life and this is still an amazing dive site. It is definitely a unique experience and one that muck divers will thoroughly enjoy.

The reef itself sits outside the bay, and its structure and topography has created a channel where water is swept through. This means that the currents can be extremely fast. This has created a wonderful place for fish to reproduce, and for larval and juvenile fish to gather. The nutrients brought in by the current feed not only the fish but also many invertebrates and it has created a dive site that is perfect for macro photographers and divers. The water can be quite cold and can reach 20 degrees and the best time to visit is during high tide or when there is an incoming tide.

The fish and invertebrates to be found here include frogfish, goby fish, dragonets such as the Mandarin fish, nudibranchs, juvenile batfish, many different seahorses and pipefish, sea urchins, wasp fish, and eels. This site has many more species that are waiting to be discovered.

The dive site is quite shallow, at around 2 to 12 meters and this is why there are so many juvenile fish to be seen. The shallow water keeps the larger fish away and so the juvenile fish are relatively safe. As it is quite sheltered as a bay, it makes for a calm dive as well. The currents are fast though and so it is normally dived as a drift dive.

It is also possible to have some spectacular night dives at secret bay. There are many different crabs, and lobsters, that can be seen.