Diving in the seas around Sri Lanka has been going on for much longer than in most other places. It all began several thousand years ago when South Indian kings developed the Pearl Fishery of the Gulf of the Mannar, employing mostly Arab divers to descend to the pearl banks to collect the oysters. This continued until the early part of the 20th century, when the Pearl Fishery was finally abandoned. True, Sri Lankans did not take part in the diving activities, and even after the advent of the aqualung they hardly rushed to the sea - with the exception of one Rodney Jonklaas - but let Europeans such as Arthur C. Clarke and Mike Wilson be the first to explore their underwater world in detail.

However, since the 1970s Sri Lankan divers have certainly come to prominence. What kind of underwater world have the islanders inherited, and what are the attractions for the visiting diver? Being a tropical island surrounded by tropical waters, Sri Lanka has diverse underwater life. Apart from the many exotic fish species, it is sometimes possible to see the range of marine mammals - whales, dolphins, porpoises and dugongs (the latter only in restricted numbers on the northwest coast). Indeed a major documentary film on the subject of whales, Whales Weep Not, was filmed off Trincomalee two decades ago.

There are coral reefs encircling much of the island, although they have suffered as reefs elsewhere from a number of adverse environmental factors. Being conveniently placed on many trade routes, Sri Lanka has attracted mariners since the dawn of navigation, and Galle and later Colombo became major destinations on the passenger routes to the east. As a result of all this sea traffic, Sri Lanka has its fair share of shipwrecks. Surprisingly, however, the inevitable treasures which stricken ships have taken to the bottom of the ocean around the island have rarely been found. One exception was the discovery by Mike Wilson in 1961 of chests full of silver coins from an unidentified wreck on the Great Basses Reef. This is described in detail in Arthur C. Clarke's Treasure of the Great Reef (1964).

Although the blue waters of the surrounding Indian Ocean are Sri Lanka's premier diving attraction, there are other brackish and freshwater possibilities as well. There are tidal lagoons with thick stands of mangroves and rocks covered with oysters. In addition there are rivers and rock pools (especially at the foot of waterfalls) that can be explored with just a face mask. Rodney Jonklaas used to talk of one at Attweltota, a lovely jungle rock pool with clear green waters, sunken long rocks, aquatic plants and lovely little tropical freshwater fishes.

There are some who come away from a diving holiday in Sri Lanka disappointed, mostly because they have encountered poor visibility. It is important to know the best times of year to visit the different dive spots around the island as water clarity changes not only according to monsoon seasons but also more localized factors such the presence of estuaries and currents. A rewarding diving expedition to Sri Lanka can be had, but it requires careful planning and impeccable timing.