Cryptocotyle thapari McIntosh, 1953 (Digenea: Heterophyidae), collected originally from a South American otter that died at the U.S. National Zoo in Washington, D.C., is redescribed from specimens obtained from a river otter, Lutra longicaudis, collected from the Río Matos in the Departamento de Beni, Bolivia. These individuals of C. thapari are slightly smaller than the type specimens, but they have similar features, including testes arranged in tandem and a well-defined ventrogenital sac. We redescribe this species because the original description was based on only 3 individuals, and the figures lacked detail. This is the first record of Cryptocotyle from any species of Lutra in South America and is the first record from an otter in Bolivia.