Bio Bio Expeditions (800-246-7238; www.bbxrafting.com), the only company offering commercial trips on the Cotahuasi, will run the river twice next summer, in June and July ($2,900 plus airfare), and lead trips down the Class III-V Apurimac in south-central Peru and the Class III Tambopata River in southeastern Peru ($1,850-$2,900). Bio Bio screens clients to make sure they are fit to handle the strenuous paddling required on the Cotahuasi and the Apurimac.
EarthQuest (206-334-3404; www.earthquestadventure.com) runs 2- to 14-day trips down the Apurimac, Tambopata, and the Class II-VI Urubamba River during summer (call for prices).
Earth River Expeditions (800-643-2784; www.earthriver.com) offers a nine-day trip in July on the Class V Colca River, about 100 miles southeast of the Cotahuasi ($2,900).
Mountain Travel Sobek (888-687-6235; www.mtsobek.com) is making the first commercial rafting trip down the Class III-IV Puyango-Tumbes River, across the border between Ecuador and Peru, next July ($3,150-$3,450).Christian Nardi