Colombia has over 1000's rivers, and as such there's great potential for all types of rafting. Though rafting in Colombia is growing in popularity, it is not yet a major adventure sport.
There are some great white water rafting opportunities near San Gil on Rio Fonce (Grade 1 to 4), Rio Chicamocha (Grade 4) and Rio Suarez (Grade 4+). Local tour operators offering whitewater rafting tours in San Gil include Aventura Total, Colombia Rafting Expeditions, Macondo Adventures, Planeta Azul and Rios y Canoas. A 90 minute rafting tour from San Gil typically costs about $15 per person.
If you are in Bogota, there's nearby rafting tours available on Rio Negro (Grade 3), which is 100km west of the capital.
Those who don't enjoy the buzz and rush of whitewater rafting will find the more tranquil balsa rafting far more appealing. Balsa rafting is a relatively new type of tourism activity in South America, but one that is highly memorable. Balsa rafts are an indigenous design made from local balsa wood (extremely light), plus bamboo, to create a raft that simply glides down rivers, though wind power is sometimes used in conjunction. Balsa rafts have been used throughout North-western South America for many centuries, and Thor Heyerdahl used this raft design for his infamous Kon Tiki Expedition. The best spot for balsa rafting in Colombia in in Quindio department, along the tranquil but beautiful Rio La Vieja. Check out www.balsaje.4t.com - don't be surprised by the dodgy homepage - click the links in Spanish.