Carlos Alonso Farrenberg (born 10 January 1980) is a Paralympic swimmer from Brazil competing mainly in category S13 events for partially sighted athletes. Farrenberg has competed at three Paralympic Games beginning with the 2008 Summer Paralympics in Beijing. He won his only medal at his home games in Rio in 2016, a silver in the 50 metres freestyle. As well as his Paralympic medal, Farrenberg has also won multiple medals at World Championship level.