You should dress for a tropical climate: cotton or silk clothes are most comfortable
(linen is too heavy). Attire on Koh Samui is absolutely informal, so light, loose
cotton clothing is most recommended. If visiting mountainous areas or national
parks, a wind breaker can be handy. When visiting temples short tight shirts or
blouses are not acceptable. Especially when exploring the night-life, tight dresses or
miniskirts are no problem. On the other hand, naked sunbathing or topless
appearance in public places is considered rude and is generally not accepted.