Pirai River

The Pirai River may refer to:
 * the Piraí River (Bolivia), a river in eastern Bolivia
 * the Piraí River (Paraná), a river of Paraná state in southern Brazil
 * the Piraí River (Rio de Janeiro), a river of Rio de Janeiro state in southeastern Brazil
 * the Piraí River (Santa Catarina), a river of Santa Catarina state in southeastern Brazil
 * the Pirai River (India), a river of India