Like in every other tropical destination, please make sure to use very high factor sun protection. Avoid to stay in the sun around midday. Especially when you go into the water, make sure to use waterproof sun protection or wear a shirt, especially if your skin is not used to the sun and even more so when snorkelling. In the water, you forget about time and what was meant to be minutes, could last hours.
Some of you may already know, but we´d like to tell you from our experience. Don´t apply sunscreen and insect protection at the same time, because insect protection may reduce the sun protection factor up to 30%! In our case, it made sun protection almost useless resulting in an extreme sunburn despite using factor 50. It´s clear anyway to apply suncream first, but after that please wait a minimum of 30 minutes before applying the insect protection.
Well, and last but not least: Drink enough water, and especially take enough water with you when doing trails and hikes. 1l is close to nothing in this hot and humid climate.