With so many divers and other visitors coming to this tiny island, the pressures on the environment, both above and below the waterline, are immense. To minimize your impact, look out for the work of a community group, Save Koh Tao, which has been formed among concerned locals and resident Westerners, with a sub-group devoted to marine conservation. Activities include a turtle-release programme, erosion control, a campaign for septic tanks to stop waste water being run straight into the sea, coral nurseries and more than half a dozen artificial reefs around Ko Tao, which allow divers to practise their skills without damaging coral. Their monthly land and underwater clean-ups are given a big splash once a year, during the two-day Underwater Festival in March, which involves mass beach-cleaning, fundraising, live bands and turtle releasing. Look out also for Sabai Jai, a free quarterly eco-travel magazine produced by the owner of Yakuzen Japanese Bath Village.
Much of what visitors can do to help is common sense: avoiding littering, recycling where possible and turning down plastic bags when you’re shopping. The island suffers from a scarcity of water, with occasional droughts during the hot season after a poor rainy season, so conserve water whenever possible. In the sea, the main rule is not to touch the coral, which may mean avoiding snorkelling when the water is low from April to September – if in doubt, ask locally for advice, be careful and go out at high tide. Don’t take away dead shells, and don’t buy coral or shell jewellery. If you’re feeling really keen, check whether your bungalow resort has a septic tank. And some dive schools have a Save Koh Tao donation box.