Expert boaters rank Cotahuasi Canyon  up with Cusco ’s Río Apurímac, another extraordinarily beautiful wilderness river with a steady stream of Class IV rapids. Colca , on the other hand, is a steeper and more closed canyon with unavoidable Class V rapids.
Rafting guides prefer Cotahuasi over Colca because there are portages around all the Class V rapids, the hillsides offer more ruins and terracing, and the river is doable even for first-time rafters. That doesn’t mean, however, that it’s not hard.
The best rafting operator in Arequipa  is Cusipata (Jerusalén 408A, tel. 054/20-3966, www.cusipata.com ), run by Gian Marco Vellutino. From April to December, Cusipata has daily half-day trips down the Río Chili, which tumbles through Arequipa and includes one Class IV chute (US$30 pp). Another excellent option is a three-day kayaking school, the last two days of which include time on the Class III waters of the Río Majes, the large downstream section of the Río Colca.
Cusipata’s more serious endeavors include descents of the Cotahuasi Canyon  twice a year in conjunction with Bio Bio Expeditions in the United States.