4 The divemaster’s island, Ko Tao (Click here) is the cheapest and easiest spot to learn how to strap on a tank and dive into the deep. The water is warm and gentle and the underwater spectacles are not to be missed. Just offshore are rocky coves and coral reefs frequented by all manner of fish, providing a snorkelling aperitif. Its small size means that the island is something of a diving ‘university’, with a lively social scene after class.