Freiberg co-drove Turner Motorsport's No. 96 BMW M3 Grand Touring Daytona (GTD) car in the 2016 IMSA SportsCar Championship North American Endurance Cup, and shared the No. 88 Starworks Motorsport Oreca FLM09 Prototype Challenge (PC) car with Mark Kvamme for the sprint races. She debuted at the season-opening 24 Hours of Daytona alongside Jens Klingmann, Bret Curtis and Marco Wittmann, finishing 22nd in the GTD class and 48th overall after multiple technical problems. During the Daytona race weekend, Freiberg earned support from the FIA Women in Motorsport Commission, making her the first North American female driver to receive recognition from the racing governing body. Two months later, she, Klingmann and Curtis finished a season-high second in the GTD class and 23rd overall at the 12 Hours of Sebring. Freiberg and Kvamme finished seventh in the PC class at both Long Beach and Laguna Seca and fifth at Belle Isle. After sitting out the mid-season races, she returned to drive for Turner Motorsports alongside Klingmann and Curtis at the season-ending Petit Le Mans, retiring before the race ended and being classified 10th in class.