Swimming with the megafauna (whale sharks and manta)
Practice snorkelling beforehand if you're not used to it, but if you are, then you'll be fine.
If seasick in the slightest, bring the necessary medicine; you don't want to waste boat time being ill.
If sensitive to the sun, be prepared to put on lots of sunscreen frequently, and take seriously covering up against the sun.
I think the program does support the local island economy.... (more)Nuraini Arsad