San Cristóbal Hiking Tour (P.O. Box 678, Barranquitas, 787/647-3402, walimai [at] hotmail [dot] com, http://barranquitaspr.org/viajes ) offers a variety of weekend excursions in San Cristóbal Cañon  from moderate hiking and biking tours to extreme rappelling and mountaineering tours. It also offers tours to Bosque Estatal Toro Negro and other natural sights in the area. Prices range $50–140, depending on the excursion and the number of people in your party.
Acampa (1211 Ave. Piñero, San Juan, 787/706-0695, info [at] acampapr [dot] com, www.acampapr.com ) offers rappelling and rock-climbing tours into San Cristóbal Cañon  for experienced adventure travelers. Explore the canyon’s waterfalls and river. Acampa also sells and rents camping, hiking, and mountaineering gear at its store in San Juan .