Both scuba diving (in which you use an oxygen cylinder) and snorkelling (more shallow underwater swimming using a bent pipe and face mask to breathe) are increasingly popular on holiday, although anyone considering the former should think about taking lessons before they go. Once you know how, the possibilities range from exploring undersea wrecks off the British coast to visiting tropical coral reefs. Admirers of the latter might like to visit the excellent special report on coral reefs at www.motherjones.com/coral_reef/ which has advice for divers on finding environmentally-sound travel companies.
Amazinscuba.com
Describing itself as a "truly independent" scuba site, this is certainly the flashiest British site in the field and may eventually become the most comprehensive, too. It offers an embryonic holiday quotes service where visitors can specify that they want to dive in, say, Tobago, and receive suggestions by email. The trip organiser section allows you to publicise your own diving trip (so far, there is just one to Cuba) or advertise for "buddies" to travel with. A very good place to start.
Aquanaut
It may have been around since 1993, but any site that claims to have had more than two billion visits is up to something fishy. Aquanaut is an international diving directory which, rather like the Pacific, seems very large but also strikingly empty.
Crystal Divers
Diving trips to an 870-acre Fijian island, with professional instructors, start from around US$1,000, although you need to fly to San Francisco in order to make onward connections. Equipment hire and diving fees are extra.
DivePembrokeshire
More than 500 wrecks apparently lie off the coast of Pembrokeshire in south- west Wales, and the area is also rich in wildlife - dolphins, trigger fish, seals and puffins. This year's captain's log, which records all the expeditions so far and those planned, is fascinating; packages are available and visitors can stay at the Dive Lodge in Little Haven. Three-day Wreck Discovery trips cost £150.
British SubAqua Club
One of the major diving organisations in Britain, BSAC sells travel insurance, trains divers, awards certificates and gives advice. Membership costs from £47 a year. The site has a special snorkelling section.
Confessions of a Mortal Diver
Or: what happens to those unfortunate divers who get the bends.
Regal Diving
Organises diving packages to the Red Sea. Divernet and the National Diving Directory both have links to numerous holiday companies.
