The trip gives you about two hours of free time to explore the island's two interpretive trails, skim through materials in the visitors center and to climb the 27m-high observation tower. For around $100 per person, a park biologist will take you on a tour of Laguna Puerto Viejo, a prime nesting site; funds go toward park upkeep and research projects. Contact the Park Headquarters on Isla Mujeres.

Amigos de Isla Contoy has a website which has good information on the island's ecology.