The go-to outfitters for rappelling in the rain forest, cave tubing, zipline rides, and hiking is EcoQuest (New San Juan Building 6471, Suite 5A, Isla Verde, 787/616-7543 or 787/529-2496, info [at] ecoquest [dot] com, www.ecoquestpr.com [1]).
Links:
[1] http://www.ecoquestpr.com