Do help preserve reef s and beaches by leaving coral and shells where you find them.
Do pay careful attention to your attire if you're female: Wearing hot pants and vests on the islands where Malaysians are used to foreigners is fine, but it may invite harassment elsewhere. At mainland beaches, bring a wrap-around as well as a swimsuit so you won't feel conspicuous; Malay women usually go swimming fully dressed and some keep their scarves on. While you wouldn't be expected to do the same, it's best not to draw attention.