Originally Posted by
El Cochinito
Oh and by the way you are supposedly not allowed to use your own sunscreen and must buy their (high priced) sunscreen which is approved for use in the waters inside the park.
Cenotes and reef snorkel/dive operations also request that visitors use biodegradable sunscreen for the health of the water (fresh water more closed cenotes especially), the reef and the creatures. All visitors to the Yucatan should use it routinely (unless you maybe don't leave the pool) and voluntarily to preserve the ecology of the area. There is a lot of information online regarding this issue. You can get it at some US sporting goods stores or online, but it is simply a higher cost product wherever you buy it.