Whale sharks are the world’s largest fish: big, gentle plankton-feeders that can grow to up to 46ft. They’re frequent visitors to Sogod Bay, in the Philippines, where Coral Cay Conservation (CCC: 0870 750 0668, www.coralcay.org) runs one of its most popular projects, surveying a coral reef damaged by deforestation.

Most of the work involves logging species underwater — and, despite the damage, there are still areas of spectacular beauty and diversity. Scuba training costs £400, scientific tuition is £700 and each con- servation week after that costs £300, full-board. Flights are not included. There are departures every month, and the minimum age is 16. CCC runs similar schemes in Fiji, Malaysia and Honduras, as well as rainforest-conservation projects in the Philippines and Malaysia.

Care for handicapped children in Mexico

Little support is provided for handicapped children in Mexico, especially those from poor backgrounds. El Tazito del Luz, a centre for 20 children with physical and mental disabilities on the Pacific coast, is an exception, and Outreach International (01458 274957, www.outreachinternational.co.uk) is looking for volunteers to provide one-to-one care. A placement, which will last at least three months, costs £3,200, full-board, including flights (minimum age 18), with departures in January, April, July or September.

Outreach also needs people to work with the victims of landmines and polio in Cam- bodia (at least three months: £3,100, including flights) and with sea turtles in Mexico (three months: £3,200, including flights).

FIND OUT MORE

Bear in mind that finding placements for gappers has grown into a mini industry, and one that is not yet regulated. Some are far better organised than others, and it’s important to ask questions when you approach them. The gap-year guru Tom Griffiths, author of Before You Go, has put together a list of things you need to know: this can be be found at www.gapyear.com/placements.

Gap-year guidebooks — such as Taking a Gap Year by Susan Griffith (Vacation Work Publications £11.95) and The Gap Year Book (Lonely Planet £12.99) — are a good source of information, as is the Year Out Group (07980 395789, www.yearoutgroup.org) an association of gap-year agencies and organisations. Another important resource is Worldwide Volunteering (01935 825588, www.wwv.org.uk), which has an online search engine that matches your skills and enthusiasms with the needs of nearly 1,000 voluntary organisations.

Organised expeditions

WHY?

Because you want to go somewhere wild and exotic, but don’t know if you could (or want to) manage on your own. These days, lots of companies offer guided expeditions for gappers, and many have adopted the formula first developed by Raleigh International: splitting your time between a trek, an environmental project, and some kind of community work, often with a language course thrown in for good measure. The variety, and security, of a highly organised programme such as this is part of the attraction for many — but if freedom’s your goal, or you want to get stuck into something more long-term, look elsewhere.

HOW?