Bali is one of over 13,000 islands in the Indonesian archipelago and is located just over 2 kilometres from the eastern tip of the island of Java and west of the island of Lombok.  Here's the map.

The main diving areas are:

• Tulamben Bay - one of the most famous diving areas on the north-east coast.  Situated in the world's richest marine biogeographic zone, it has more than 2500 different species of fish and 700 corals.  The bay receives very plankton rich water from the major ocean current that moves from the Pacific to the Indian Ocean and vice versa. 
• Amed - located on the northeast coast of Bali.  In April and May 1998, this reef was badly affected by coral bleaching as a result of El Nino down to a depth of 12 metres. The upper reef is slowly recovering, but it is uncertain when it will return to its original splendour. The deeper reef fared better with the gorgonians and corals untouched.
• Menjangan Island - located in the northwest of Bali and part of West Bali National Park, declared in 1982.  Entry and diving on the island is controlled by the Park Service.  In 1978 Menjangan became Bali's first internationally recognized diving location due to its beautiful flat reef.  In 1997, the extensive flat reef at the island suffered damage from Crown of Thorns starfish, and again in 1998 from coral bleaching as a result of El Nino.  However the walls for which Menjangan is most famous are still in excellent condition.
• Padang Bai for some of the best diving in Bali. Sharks are seen on almost every dive, ocean sunfish are regularly spotted, fish life is exceptionally rich, the coral is healthy and the water is crystal clear.
• Nusa Penida - most of the dive sites around Nusa Penida and its two small sister islands, Nusa Lembongan and Nusa Ceningan, are drift dives (the current can reach more than 4 knots.)

Annabel Thomas is Director of AquaMarine Diving, a PADI 5 Star Dive Resort in Bali and Indonesia's first Project AWARE Go ECO Operator.  Download Annabel’s PADI Magazine (Undersea Journal) article about Diving in Bali here.

• Tulamben Wall - for a magnificent purple gorgonian sea fan at about 28 meters that is over 2 meters in diameter.  There are big bumphead parrotfish, ghost pipefish and cometfish. The area also seems to attract a lot of lionfish for some unknown reason.
• Kelebit Rocks - a 15 minute boat ride from Tulamben Bay, the water is cooler and the fish life is different. Visibility is often better and larger predators come in to feed including sharks and barracuda. Hammerheads and Mantas have been spotted at this dive site.
• Paradise Reef - also called Coral Garden or simply House Reef. Marine life is extremely diverse and you will see ribbon eels, octopus, anemonefish, harlequin shrimp, morays, and many juvenile species. Also a great night dive venue where Spanish dancers alongside boxer and hairy crabs can be found.
• Nusa Penida - pelagics are the main attraction here; sharks are common and big mantas are frequently sighted. However, the unique Mola-Mola or Ocean Sunfish are sighted from August to September.  Read Phil Tobin's report of his extraordinary encounter with ten of these magical creatures.

• The best diving in Menjangan Island is during the southeast monsoon (April to November).  However, you can dive here anytime of the year, choosing sites on the north or south of the island depending on the direction of the wind. The visibility can often be amazing - probably the best in Bali - especially in October and November with visibility in excess of 50 metres.  Current here is very rare, even 1 knot is unusual around the island.
• Padang Bai dive sites have strong currents and swell coming from the Lombok Strait, creating unpredictable water movements.  Be warned!
• There remains a high threat from terrorism in Indonesia.  Check current Foreign Office Advice before travelling to any part of Indonesia.
• You should seek medical advice before travelling to any part of Indonesia and ensure that all appropriate vaccinations are up-to-date.  Click here full details from the National Travel Health and Centre.