There are other health issues you need to be aware of during your visit. In the last years the number of dengui cases increased, especially on remote islands like Koh Chang, Koh Tao and Koh Phangan. The symptoms are similar to malaria. There is no preventative medications for dengui fever, in case of symptoms see the nearest doctor or hospital. There is only one secure precaution against AIDS and other venereal diseases and that is the use of Condoms.
Condoms are readily available in almost every supermarket and every pharmacy.
Don't let yourself get dragged away by unprotected tropical passion. Better be prepared to avoid unwanted souvenirs. Sun Don't underestimate the tropical sun. Even when it is cloudy you can easily get burned. Bring a sunscreen from home to protect yourself.