The child was taken to a hospital for treatment on June 14 and was released the next day, Universal spokesman Tom Schroder recently told the Orlando Sentinel.
The incident happened at the Kala and Tai Nui Serpentine Body Slides, according to a quarterly report in which the major theme parks voluntarily disclose whether their visitors were hurt on a ride and hospitalized for at least 24 hours. The report covers the period from April through June, when most of the state's theme parks were closed.
Universal was the first to reopen to guests on June 5.
Schroder didn't disclose any additional details about the boy's injuries. Passengers on the ride, which is atop the iconic volcano, go through drop doors into enclosed tubes before splashing into a pool.
The reports are released by the Florida Department of Agriculture and Consumer Services. They only include the person's sex and age, along with the name of the ride, date of the incident and limited details.